BACKGROUND


Ever since the introduction of the 3.5mm headphone-jack-omitted iPhone 7 in 2016, along with the subsequent release of competing smartphones following suit, the market for affordable bluetooth earphones has grown substantially. I originally dismissed bluetooth earphones and headphones as being inferior to their wired counterparts in both convenience (they must be charged) and in sound quality. Ever since I bought my iPhone 7, however, being all but forced to use wireless headphones (lest I use that pesky little lightning-to-3.5mm dongle) has made me an unexpected believer in this technology. I have found that once I have gone wireless, I struggle to return to snag-happy wired headphones, especially when I am moving about. This concern for having a pair of earphones that lack free dangling wires has become exponentially more crucial when I perform intense cardio sessions. My need for a pair of bluetooth earphones that stayed secure in my ears whilst enduring perspiration (sweating) presented the challenge to find a suitable and affordable fitness headset. QCY Audio rose to this challenge, and kindly reached out to offer me the opportunity to review one of their newest bluetooth sports earphones, the QY25 Plus.


WHAT’S IN THE BOX?


The QY25 Plus comes nicely packaged in a cardboard display-style box with a magnetic flap, complete with a set of small and large eartips; the medium eartips are preinstalled. There is also a short micro USB charging cable included.


FORM FACTOR AND WEARING COMFORT


The QY25 Plus is a fitness and convenience-focused pair of neckband bluetooth earphones. There are two color wave options to choose from: black with lime green wires, and gray and white. My unit was the white model. The neckband is a light gray rubber-coated metal wire, with two plastic, rubber-cushioned dongles at the end of each side of the band. The white earphones attach to wires that terminate from both of these dongles. I previously used bluetooth earphones that simply connect with one wire, but I have found that this design often forces manufactures to place the batteries, bluetooth antennas and audio circuitry in the ear capsules themselves, causing the earphones to protrude excessively from my ears, and becoming excessively bulky and heavy, easily falling out of my ears. The QY25 Plus solves this problem by having its circuitry and batteries located at the dongle ends of the neckband, allowing the earphones to remain light and compact, comparable to the size of traditional wired earphone capsules. This results in the QY25 Plus being an extraordinarily comfortable pair of bluetooth earphones. The earphones stay comfortable in my ear canals by just the silicone eartips, without the need for uncomfortable hooks that dig into the backs of my ears, or wings that make the concha bowls of my ears incredibly sore. The QY25 Plus stays in securely, whether I am running on an elliptical machine, walking or at my work desk. The dongles on the end of the headband have a tendency to bounce around a bit when I am running, but I can easily tuck them underneath the collar of my shirt. I can easily wear the QY25 Plus all day long around my neck with no issues whatsoever, and the magnetic metal ends of the ear capsules allow the earphones to attach together so they do not flap around loosely.


The right dongle on the neckband contains the play/pause button, the volume buttons, the power switch, the microphone, the charging port, and the vibration motor. The button for play/pause button/answer call/redial (does not work with Siri) is located on top of the dongle. The volume buttons (that also can skip or replay tracks by being held down) are easy to reach and are located on the outside of the dongle. The power switch is located on the inside of the dongle next to the blue/red charging, connection, and power indicator LED. When you turn the QY25 Plus on, you will hear a brief melody played (as well as when you turn the QY25 Plus off), and you will feel a long vibration from the right dongle. The vibration function works for incoming phone calls, but having a vibration for text and email notifications would have been nice as well. Bluetooth connection is version 4.1, and I experienced no issues with electronic buzzing or chirping sounds. The Bluetooth connection signal stayed strong for about 30-40 feet before the QY25 Plus lost the signal from my iPhone. The QY25 Plus is a good headset as well: phone call quality was adequate, with clarity from both ends of the call.


CHARGING AND BATTERY LIFE


The QY25 Plus is good for 5 hours of battery life, and once the battery level dips below 10 percent, the earphones give off a warning beep. Recharging is accomplished via micro USB, with the charging port located on the inside of the right dongle covered by a silicone flap, requiring a bit of prying with the fingernails to open. The QY25 Plus charges in approximately 1 hour off of any sort of USB power connection, and indicates a complete charge by illuminating the solid blue LED.


ISOLATION AND SOUND QUALITY


Once you have the eartips securely placed in the ear canals, sound isolation is good, and comparable to a good pair of closed back headphones. The QY25 Plus is definitely a sound isolation step up from Apple earphones, and the earphone nozzles are a fairly universal size, which may suit those who want to eartip roll to seek even better noise isolation or tailor the sound more to their liking.


And now onto the sound….


HIGHS


The QY25 Plus has a fairly smoothed over treble, with decent articulation, though on the darker side. Darker treble is fine for a pair of fitness earphones, since having a ton of treble while doing exercise tends to hurt my ears (though some of you may like a treble assault while you are running). Sibilances were not harsh at all, and neither was harsh guitar work. I did notice that the treble could get a bit slurred on some harsher and faster genres, but for what the headphones are, that is perfectly acceptable.


MIDS


Mids and vocals on the QY25 Plus are good quality considering the form factor, purpose and price of these earphones. Often times, more affordable headphones and earphones tend to be plagued with a tinny, nasty upper midrange. The QY25 Plus has a touch of graininess in the upper midrange, though not to any extreme, and is not a deal breaker whatsoever. Vocals and mids tend to be a bit on the darker side and take a bit of a step back to the bass, but there is plenty of clarity to enjoy your favorite music, videos and podcasts while exercising. QCY Audio reports the QY25 Plus as supporting aptX bluetooth audio quality, but I do not have a source device that supports this format, so I am unfortunately unable to comment any further here.


LOWS


Bass is where the QY25 Plus shines. There is plenty of middle and sub bass to enjoy all the dance, house, hip-hop, drum and bass, and K-Pop that I want, and the bass speed keeps up with fast genres. There is a bit of a dip in the upper bass, combined with the more laid back mids, but the midbass still keeps the pace going. These are definitely a fun and driving set of earbuds for those who demand a fast and thumpy listen for their cardio or weight training sessions, myself included.


MY CLOSING THOUGHTS


The QY25 Plus is definitely a bass-emphasized, fun-sounding, affordable pair of sport neckband earphones, and has become my go-to, portable work/walking/fitness pair of earphones that suits most of my genre preferences. I highly recommend these earphones to anyone looking for a solid, affordable pair of sports Bluetooth neckband earphones. These days with the push toward wireless connectivity and the abandonment of wired peripheral support from mainstream wireless media sources, the market in good-sounding, affordable audio products continues to grow exponentially by the day. The QY25 Plus is one of these latest products that holds its own. I would like to thank the folks at QCY Audio for providing me with this unit, and giving me the opportunity to review one of their products.


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DISCLAIMER: This is a unit that Smartomi sent to me to review.


Design

The MOTTO are wireless Bluetooth earphones that have a dongle on the end, attached to two-foot cables that terminate to an inner-ear-outer-ear earbud. The earbud design is somewhat reminiscent to Sony earphones, and has a spun metal decorate cap on the end.


The MOTTO’s dongle is made from plastic and houses the internal lithium polymer battery, the play/pause/power/pairing button, a volume rocker switch, and a slider switch that turns the noise cancelling mode on or off. On the back of the dongle is a spring-loaded shirt clip that you attach to your shirt or lapel. On the bottom of the dongle is a micro USB port for charging the earphones, and a 3.5 audio input jack for connecting to your source device should the battery go dead (a simple 3.5-3.5mm cable is included). Also included are a couple pairs of different-sized silicon ear tips, and rubber rings you can put in place should you choose to remove the silicon outer-ear guides. You also get micro USB cable, and a nice zipper neoprene-feeling pouch to store the MOTTO in your bag.


Comfort

As I mentioned before, the MOTTO is an inner-outer-ear design, which means the silicon tips go into the inner ear, but the body of the earphone rests in the outer ear in a bud design. This earbud design means that the earphones remain very comfortable for wearing for long periods of time, and are easy to insert in the ears. On the flip side, however, the earbud design means that passive noise isolation is average at best, and there is quite a bit of ambient sound that comes in. The other downside is that the earbud design means these earphones sit loosely in my ears, and have a greater tendency of falling out. To counteract this problem, the MOTTO has silicon ear guide hoops that put pressure on the top part of the outer ear canal to stay put. I personally would have preferred an outer-ear wing guide design that stays put better, and braces against more of the outer ear.


Bluetooth and Controls

The MOTTO connects via Bluetooth, and has an NFC chip for easy pairing to Android phones. I used the MOTTO with my iPhone 7, and I was able to achieve a steady connection with little hangup time before the earphones connected. My one complaint is that there is some audible chirping and radio noise when I have MOTTO connected, and I am in a quiet environment. In a commuting environment, however, there was little issue.


The volume controls work with the iPhone, but I did notice that the volume increases and decreases by two steps, instead of one step. The play and pause control works fine for my iPhone, but there is no Siri or voice assistant function, so holding down the play/pause button will turn off the earphones. Another bonus is that these earphones also have a microphone located on the right cable leading to the earbud, which allows you to make phone calls or video calls. I tried out the microphone, and I came in loud and clear to the person on the other end.


The battery is quoted at 7 hours, and in my testing, I achieved 6-7 hours. Charging takes around 3 hours, and these headphones can be charged by ay micro USB cable. Smartomi does recommend against plugging these headphones into a wall outlet adapter like you get on smartphones, so I charged them off either my laptop, or my small external batteries.


Noise Cancellation

As someone who is spoilt by the best-in-class active noise cancellation (ANC) of the Bose QuietComfort series, I honestly thought that the ANC on the MOTTO was going to be subpar at best. Much to my surprise however, it is actually quite good, especially given the price of these earphones. No, the MOTTO is not going to rival the ANC performance of a Bose QC35 or a Sony MDR-1000X, but it performs better than its price would suggest. Keep in mind that the ANC is not as quiet as those other, far more expensive products, so there will be some audible hissing. When I turned on the ANC while riding the bus, the MOTTO provided a great deal of active noise cancellation (from road noise, roar from the engine and heaters running). I switched off the ANC mode just to be sure, and indeed there was an audible difference in the ambient sound level. Keep in mind that the earphones are an outer earbud design that fits somewhat loosely in the outer ear, so passive noise isolation is not fantastic. On the flip side, this little isolation means that you can turn off the ANC mode, and hear enough ambient noise to be aware of your surroundings while you walk around. I recommend, however, that one always takes an earbud out of one ear before they do something like cross a street.


Sound

These earphones have a good sound for their price. I do notice, however, that they fall a little short in their midrange presence. They are somewhat withdrawn, so an EQ boost to the midrange helps to even out the sound. Bass is mostly neutral, but does have a little extra thump in the lower midbass, so the MOTTO keeps up nicely with hip-hop, pop and dance music. ANC mode seems to add a little bass boost, and makes the sound weightier than when the ANC is turned off.

The treble doesn’t seem to have any issues with spikes or other trouble spots, so I have no complaints there. For a feature-packed earphone that costs less than 60 dollars, the MOTTO’s sound quality holds up well.


Overall Thoughts

I originally thought I was not going to like the Smartomi MOTTO, since I have been so accustomed to much more expensive wireless and ANC devices. By the time of this review, however, I was impressed with how well these earphones hold their own in features and ANC performance. At such a low price for what you are getting, the MOTTO makes for a great commuting earphone. They aren’t the best for working out, since the earbuds will probably slip out, but for causal use in mobile settings, these are a great option.


What I would like to see in a future version is more midrange, a little less hiss from the ANC circuitry, and ear guides that have a wing design, which would help to make the earbuds more secure in the ears. Overall, though, the MOTTO is a great value for the money, and I would recommend it to people looking for an affordable wireless earphone for public transit commutes. I would like to thank Jennifer and the staff at Smartomi for kindly sending me the MOTTO to review.

Design


The WIT is not a hugely revolutionary design, but is solidly made. The body of the earpieces is a satin plastic finish, and the back decorative plates are made from brushed aluminum. The cable is soft coated, with a plastic remote dongle with satisfyingly tactile large silicon buttons that are easy to feel. The buttons are a standard 3 button affair, with the top and bottom being volume control, and the center being controlling play/pause, on/off, and pairing. One thing to note is that the center button has no functionality as a Siri control for iOS. Holding down the center button will turn off the headset. The WIT is sweat resistant, so you should not need to worry about shorting it out if you are the perspiring type.


Ear fit and Isolation


The WIT is an earbud/in ear design, which means there is a silicon tip fitted to the nozzle that goes in your ear canal, while the rest of the bud that contains the driver rests in the outer ear. The design is very comfortable, though the drawback is that isolation is not great. This is a good thing if you are running outside and still need to hear your surroundings, but not such a good thing if you are listening in a noisy environment. To secure the WIT on the ears, there are built-in bendable ear guides made from metal and jacketed in a durable silicone. With the ear guides properly fitted around my ears, I found that I could get a secure and comfortable fit from the WIT, and had no problem running on the elliptical machine.


Charging and Battery Life


The WIT is rated at 8 hours of charge, which in my testing I found to be accurate. Charging is done via micro USB, for which a cable is included, and takes about 2 hours at the most. When the earphones are about to die, the voice prompt announces “battery low”. The WIT will take a charge from an external battery pack, but I would not recommend charging the earphones off a cellphone USB wall power adapter, as it may put out too much voltage.


Connectivity and Headset Use


The WIT was able to maintain a steady and quick connection to my iPhone, which when established is announced by a voice prompt in the form of a British woman stating “your headset is connected”, immediately followed by a single beep. As a headset, calls came in clear and people on the other line could hear me clearly, though the microphone on the dongle tended to pick of a bit of wind noise. As far as Bluetooth noise goes, the WIT has some white noise that is noticeable in the background, but for the environments in which I listen to the WIT (i.e. in gyms and on the street with loud music), this fuzzing noise is rarely bothersome. For those of you to whom this would be a concern, be aware that the WIT exhibits this issue.


Sound


The WIT was quite a surprise to me, because I thought that at its low price, it would sound like a harsh mess. On the contrary, I found it to be a wireless earphone with a nicely detailed and present midrange and vocal presence. There is some upper midrange glare that I find is often characteristic in low cost headphones and earphones, but it does not rear its head in often enough to be much of an issue. Treble is fairly neutral, with good attack and decay. Bass is a bit of a shortcoming due to the fact that the earphones sit in the outer ear, and do not form a tight seal in the inner ear. There is some decent midbass and upper bass punch, though sub bass is rolled off. I would have liked more mid bass and sub bass, as having a powerful driving beat is something many of us, myself included, look for in an exercise earphone like the WIT. As I listen to bass-heavy genres such as dance, house music and drum & bass when I do cardio exercises, and hip-hop for weight training, an equally powerful bass slam to match the WIT’s articulate midrange would round out these earphones perfectly.


Summary


Overall, I enjoy Smartomi’s WIT, and I regularly use it for my both routine workouts and as a walking around earphone. With a more powerful bass punch, the WIT would be a perfect workout earphone in my book. Considering its low price and plentiful 8-hour battery life however, the WIT is great value for money, and gets a strong recommendation from me for anyone looking to buy an affordable Bluetooth exercise headset. The fact that the WIT exists as a Bluetooth earphone with this good of a midrange, an excellent 8-hour battery life, and a sub-30-dollar price tag indicates that the market for Bluetooth audio is truly in its element today, and is rapidly maturing. For the average consumer, there are now so many choices of excellent Bluetooth devices to be had at any sort of price range, with any feature one could want. The future looks bright for high quality Bluetooth audio devices at great prices, and the WIT certainly establishes itself among them.

Introduction

To preface this review, I have owned a number of headphones prior to buying the DT1990 Pros. I owned Beyers including the DT990 Pro, the DT880 Pro, and the DT150 Pro. I also owned the Sennheiser HD580 and HD650, and until recently, I was a huge fan of AKGs, having the K702 65th Anniversary, the K612, the K7XX and the K712 Pro. Believe me when I say this: the DT 1990 Pro is the best sounding neutral headphone I have ever bought, beating out my Audioquest Nighthawk (my comparison will come in a different article) to be my open back home listening headphone of choice.

Build

Like an absolute tank: Hand built in Germany at the Heilbronn factory. The 1990s are among the three newest 600-dollar, 250-ohm full-size Tesla headphones, the others being the closed DT1770 Pro, and the consumer-oriented Amiron Home. This is the latest iteration of the DT design, with more touches of refinement to this tried-and-true design. The 1990 is made up of metal and high impact plastics. The ear cups are plastic on the side, with laser-cut aluminum driver covers on the face and a fine mesh metal grill beneath. The hinges are fastened with torx screws with metal swivels, and the bales are finished in dark gray metal. The headband is now made from stitched protein leather, and the ear pads are velour with memory foam padding. This is the most refined DT model to date, and it remains rugged yet elegant. I expect this headphone to last a couple of decades easily.

Accessories

The 1990s come with a vinyl zip-up case, two sets of ear pads (more onto that in the sound section), and two cables: one 3 meters and straight, and the other 5 meters and coiled; as well as two 6.3mm stereo plug adaptors. The straight cable does tend to keep its wound-up memory, and is not as pliable as the cable on the Amiron Home or the Sennhesier HD650, but it has a nice rubber texture to it, is properly thick, and just like the heavier coiled cable, it terminates to the output device in an aluminum jack body with rubber strain reliefs. The good news is that since these cables are detachable and terminate to a 3-pin mini XLR termination, you can use shorter custom cables or AKG cables. If you want to run these headphones balanced, you will have to rip out the interconnect wire, and drill into the ear cups. The Amiron Home is the better headphone to run balanced, since it uses dual-entry cable connectors, making it possible to use a balanced cable by plugging one in. For a headphone of this price, the DT 1990 comes properly accessorized.

Comfort

This is really the only stumbling block for the DT 1990 in my opinion, and I think it is simply due to the age of the design in an era where headphones are getting more advanced with their ear chamber designs (think Sennheiser HD700 or HD800, and the Audioquest Nighthawk). The 1990s are still comfortable headphones, but with a couple footnotes. Allow me to further explain.

The velour ear pads (both pairs) now contain memory foam, and should maintain their shape nicely over time (something the Sennheiser HD600 and 650 are notorious for not doing). The only trouble is that the drivers sit flat and parallel to your head, and are not angled like the Beyerdynamic T1 or the Sennheiser HD800. This combined with the not-particularly-deep earcups means that my ears touch the driver covers, which drives me insane. To remedy this, I have to stuff in rolled up tissue paper underneath the lips of the ear pads to give my ears more room to tuck in. It's a bit of an inelegant solution, but it helps noticeably in keeping the drivers away from my ears. My other complaint is that the spring steel headband helps to keep the headphones indestructible, but it also means that these headphones clamp like a Sennheiser HD600, which contributes to the drivers touching my ears. The 1990 is still a comfortable headphone, but it never disappears when you are wearing it.

The weight of the headphones is 370 grams, which is quite substantial, and likely due to the rugged design. Thankfully, the headband, which has ample-but-firm padding, helps to distribute the weight of the headphones evenly across my head, preventing me from developing any hot spots. If you want a headphone that clamps less over the head, and has a softer headband, then try the Amiron Home instead. Overall, with some modifications to the ear pads, the DT 1990 Pro remains a secure and comfortable headphone on the head.

Amplification

The DT1990 Pro only comes in 250 ohms of impedance, however Beyerdynamic seems to have tuned the headphone to work easily with a variety of sound systems. Firstly, the 1990 has a 102 decibel-per-miliwatt sensitivity, so it is surprisingly easy to drive loud. Secondly, the high sensitivity and high impedance combination makes the 1990 an easy headphone to drive on a variety of amplifiers. I have driven them from the headphone jack on my 2011 MacBook Pro and Lightning-to-3.5mm adapter DAC that came with my iPhone 7, and in both situations the sound quality was not half bad...may I say even decent. The 250 impedance makes the 1990s suitable for listening to on an OTL tube amplifier such as the Woo Audio WA3, Schiit Valhalla 2 or Bottlehead Crack.

I personally run my DT 1990s on my Schiit Lyr 2 with upgraded tubes, and I find that the combination does add some treble brightness to the headphones, but the Lyr 2 helps to make the sub bass even deeper, and increases the sense of scale and largeness to the sound. The other device I run my DT 1990s on, even more so than the Lyr 2, is the Chord Electronics Mojo. While I find the scale of the sound is not as large, the soundstage is more compressed and the bass may not be as powerful in the lowest frequencies as the Lyr 2, this amazing little FPGA DAC/amp works wonders with the DT 1990, keeping its powerful bass while making the sound signature as effortless and as smooth as can be.

The DT 1990 Pro in my opinion is a wonderful headphone to use with different setups, and its impedance reminds me a great deal of the Sennheiser HD650: a high enough impedance to use with any amp, while retaining a sensitivity and dampening factor that makes the headphone maintain its basic sound signature regardless of what you plug it into. This is an easy headphone to work with, but if you can achieve the right sound system synergy, the rewards will be well worth it.

And finally...

Sound

The DT 1990 in my opinion is a neutral headphone tuned for the music we listen to today, while never compromising itself to the temptation of sounding overly colored. This is what I mean:

Bass

The bass on the analytical ear pads (4 vent holes) is about as flat and neutral as you can get, without ever sounding boomy, bloated or one note. More importantly, the bass doesn't fall flat at the lower frequencies, nor does it sound dull and anemic with modern genres like the AKG K7s have the tendency to do. It's the ideal balance of texture, impact and tonality to my ears for neutral listening. My only possible complaint is that the upper bass is not as warm as other headphones like the Sennheiser HD650, which does not add a sense of grooviness to the mids and rhythms, but that is what the Amiron Home is for.

With the balanced pads (20 vent holes), the DT 1990's mid bass and lower bass frequencies pick up a few more decibels, making the headphone a fun hip-hop dance music and drum n' bass headphone. With the balanced pads on, the classic Beyer bass rumble comes back, which is what I love about the Beyer sound signature. It comes down to personal preference, but I enjoy the extra thump and rumble from the balanced pads, since I listen to a ton of hip-hop, house and drum n'bass. If you want a little more presence to the mids and you want as flat a bass response as you can get, then try the analytical pads.

Mids

Regardless of the pads you use, the mids on the DT1990 Pros are simply outstanding. To AKG and Sennheiser fans, they may find that the DT 1990 Pros are not forward enough, or have that Beyerdynamic "dip" to them. That in my opinion is due to the fact that the upper bass is not pushed forward, and neither is the upper midrange. This means, however, that the mids are neither stuffy, nor shouty with women singers and brass instruments. Yes the DT 1990 has a less bloomy midrange with less rawness than other headphones, but at the same time it makes the DT1990 surprisingly musical without sounding overly mechanical like the DT 880 and DT 990 could be. What I love so much about the DT 1990's midrange more than anything else is its smoothness and its tonality, which in absence of other words sounds "right". There isn't an off-sounding timbre or spot where it sounds too warm or too dry or comes off as dull. Maybe this has something to do with the Tesla magnets, but the DT 1990 has that rare ability to sound uncolored yet highly musical and fun, which few other headphones under 1000 dollars do, aside from the Sennheiser HD650 or HD600.

Treble

Just like the mids, this is where the DT 1990 shows its improvements over older Beyers. The treble is mostly neutral with a some stored energy in the mid to upper highs. If you thought the DT 990 Pro was too metallic and spiky in the treble, then you will be in for a pleasant surprise. Beyers never in my opinion had roughness of graininess in their treble, but the problem in my opinion was that they were tuned less to human listening tastes (Harman Response Curve, for example) and more toward a Diffuse Field signature. This causes Beyers to have a metallic, sibilant treble that people more accustomed to headphones with a more neutral or softer treble will often hate. Beyerdynamic put in a considerable effort to address this problem. The DT 1990 loses much of its overt brightness in exchange for just enough treble to add the correct tonality to symbols and hi hats. It's not a dark headphone at all, just a neutral one to my ears, and I am someone who is sensitive to treble spikes. My only complaint is that there is still a small bit of metallicness in the sibilance range, but it only rears itself in on the spikiest of tracks, or when being driven on an overly bright amplifier.

Soundstage

Soundstage is probably the least noteworthy sound aspect of the DT 1990 Pro. That is not to say that it is overly compressed or blobby and indistinct in its precise placement like a Sennheiser HD650 can be to some people, but the soundstage does not have the width and the depth that I have been used to on my AKG K712 Pro. Nevertheless, the soundstage is medium in height and width, with accurate instrument placement. You will never mistake the DT 1990 Pro for a set of room speakers, however. And that leads me to my conclusion...

Conclusion

The Beyerdynamic DT 1990 to me is the headphone that is most unapologetic about being a headphone. The mids and the soundstage never try to imitate room speakers, and the sound lies solidly on the neutral side. If the Amiron Home is the next step up from the Sennheiser HD650, then the DT 1990 Pro is the next step up from the HD 600. And in many ways, the two share the qualities of what makes a headphone truly great. I find that the best headphones out there often do not master one particular feat perfectly, lacking in the other areas. A truly great headphone is one that does everything well. And that's what the DT 1990 Pro does. No it doesn't shake your head off with bass, no it doesn't scratch the inside of your head with treble, no it doesn't feel like a driving moccasin (or whatever light slipper you may wish) for your head like the Bose QC35, and no the soundstage won't trick you into thinking you are in a concert hall watching a live performance. That doesn't matter in the end, because the DT 1990 Pro is a headphone that covers all the bases, and never makes you feel as though you are missing out on something. And that is what you should get with a great neutral headphone, and something that is often ignored with colored headphones that try to suit a specific mood or genre at the expensive of everything else. The Beyerdyamic DT 1990 Pro is the Audi R8 of headphones because much like its German automotive spiritual sibling, it performs neutrally and it hangs with its more prestigious and more expensive competitors, while not beating its chest about it. While it is not cheap, the DT 1990 Pro may be all you will ever need in an open back headphone in the sub-1000 dollar price range, and that is what truly makes it a great headphone.

Putting the Mojo into Perspective:
 
The Mojo competes more with high-end portable DAC/amps like the Centrance HIfi-M8, the Cypher Labs Theorem 720 (now discontinued), and the considerably more expensive Sony PHA-3. So when considering those competitor prices, the 600 dollar MSRP of the Mojo does not seem as exorbitant. In addition, it is about 1/4^th the price of the Chord Hugo, and while it may not have as many features like RCA line out, the Mojo is a great compromise.
 
Build Quality:
 
Made in England, The Mojo is about the size of a stack of 52 playing cards or a pack of cigarettes, so it fits perfectly in the hand. It is heavier than one would expect considering its size, at 0.4 lbs, or 182 g. The Mojo is made from a single piece of black-anodized aluminum, with the Mojo name and Chord company name laser etched onto the finish. There are also four soft silicone feet affixed to the bottom of the Mojo, which prevents the Mojo from sliding around on the table or when attached to a phone, and having its underbelly scratched. The only slight rattling you may hear is from the acrylic marbles, but other than that the Mojo is as solid as a volcanic rock. There are also divets on each corner of the top of the Mojo to help secure rubber bands to it. It’s a precisely made yet elegantly simplistic and modern-looking device. Importantly for Astell and Kern AK100 and AK120 users, the Mojo is about the same height and width of those devices, so it should strap together nicely.
 
 
Connectivity:
 
The Mojo can be connected via three different digital connection ports: Micro USB, 3.5 mm Coaxial, and a standard TOSLINK/SPDIF Optical input. There isn’t a dedicated line-out jack, but you can switch the Mojo to a fixed-level line-out 3v mode by simultaneously pressing the up and down volume buttons once while immediately after powering on the Mojo. Line-out mode is indicated by the two volume marbles turning a lilac purple color. While I have not connected the Mojo to my Schiit Lyr 2 Class A hybrid tube/solid state headphone amplifier yet, I have a friend who runs the Mojo out via line-level to his solid state Violectric HPA-V200 headphone amplifier, and he is more than satisfied with the synergy. Some users have complained that they had experience clipping issues while plugging their Mojos in this mode to a stereo system, so your mileage may vary. Also, the Mojo will automatically switch out of line-level out mode when you turn off the device and turn it back on again, to prevent users from making the mistake of connecting their headphones and blowing out the drivers/their ears. To set the Mojo to remember line-out mode, simply press the minus volume button once, and then immediately press the volume up button once, while the Mojo is in line-out mode. This is useful if you keep your Mojo plugged into a desktop amplifier and do not want to have to keep switching to this mode every time you power on the device. Also, keep in mind that the Mojo, unlike the Hugo, does not have a manual input source button, so it automatically prioritizes the USB input, then the coaxial and optical inputs. If you have the Mojo connected to a coaxial or optical source, make sure you disconnect any Micro USB cable from the digital-in port. The Micro USB power socket is an entirely separate port from the Micro USB digital-in port, so it won’t affect the source connection.
 
I recently discovered that my 2011 MacBook Pro 13 inch has SPDIF optical out via a Mini Toslink connector built into the headphone jack, so I have been running the Mojo that way. In my opinion, if you have a laptop with USB ports that have power issues and distortion problems, then see if your computer supports optical out, because running the Mojo on optical for me not only cut down on distortion and interference noises from a USB DAC, but it also brought back a ton of bass impact that was lost when I ran it off the USB ports. 
 
Volume Adjustment and Controls Explained
 
 
The Mojo is rated at 75 miliohms, so the output impedance is ideal for use with super sensitive IEMs and 600 ohm full-size headphones alike. Unlike the OPPO HA2-SE or Centrance HIFI-M8, the volume adjustment on the Mojo is digital and not analog. This means that although adjusting the volume can be a somewhat slower affair, the FPGA (Field-Programmable Gate Array) chip on the Mojo is able to recall the last volume setting you set on it prior to switching it off; something the Hugo did not have. This is an immense help if you need to fine tune the volume setting on a sensitive headphone/IEM that you frequently use, and do not want the frustration of having to constantly readjust the volume every time you switch the Mojo on and off. While I do not own a highly sensitive IEM, I did try the Mee audio M6 Pro’s, and the background was dead silent on the Mojo. This is a tuly capable device. The headphone impedance is adjusted to by the Mojo, so there is a great deal of electronic wizardry going on under the hood of the Mojo, certainly more than what meets the eye.
 
The volume level is indicated by the volume marbles changing colors. And volume range is indicated by a color gamut that follows the spectrum of the rainbow. For the lowest volume level, the color is a reddish-brown. This switches to red, then orange, then to yellow, greens, blues (such as cobalt blue, electric blue, cyan, etc), then to purples near the top of the volume range, and then finally to white. At the lowest volume range, you enter a low gain adjustment mode, where the volume up button stays a pinkish red, and the minus button descends through the rainbow from white down to red before both button LEDs switch off. The top of the volume range is high level, and is indicated by the minus button lighting up white, and volume up button starting with pink/red and ending in white. While unconventional and requiring a little getting used to, this in fact is a highly unique design, and becomes intuitive in no time at all. It’s a detail that adds a special compliment to the Mojo’s design, while being a standout feature that as far as I can tell, no other company has done with a device like this before.
 
Accessories:
 
If you buy the Mojo and you do not have all the accessories you need to get it started and hooked up to the devices of your choice, then consider investing 100 dollars in the Mojo Cable Accessory Pack.
 
In it you get:
 
*Two sets of silicone bands of two different sizes for strapping the Mojo to your device
*A Micro USB Cable
*A Micro USB Cable with two Micro USB jacks to both connect and charge the Mojo at the same time.
*A 6.3mm to 3.5mm adaptor to run ¼ inch jacks of headphones off the 3.5mm jacks on the Mojo, similar to the adaptor you get on the Sennheiser HD650.
*A 3.5mm to standard Optical cable
*A regular optical cable
*An OTG Micro USB to Micro cable for plugging into an Android phone
*A Micro USB to female USB A adaptor
*A Ferrite Suppressor for fitting around one of your USB cables, in other to cut down on signal noise.
*And most importantly for iPhone users, the USB adaptor module. I will further discuss this in the iPhone connectivity section.
 
While 100 dollars might seem like a steep price to pay, it is convenient to get everything you need for the Mojo, and I think in the grand scheme of things is worth the investment. Keep in mind, though, that you will have to still buy the 30 dollar USB Female to Lightning adaptor from Apple, called the CCK.
 
 
Charging the Battery and Usage:
 
Now I have not been able to find any information on the Mojo’s battery size, but Mojo rates it as 8-10 hours of battery life when powering most headphones. The battery life is indicated by a small LED next to the charge port that lights up blue on a full charge, turns green below 75 percent, yellow below 50 percent, red below 25 percent, and flashes red when the battery is less than 10 percent, and is about to die. From my usage, the maximum 10-hour life seems spot on and consistent; I can easily get through a full day from the battery. The Mojo charges off a standard micro USB cable, which uses its own separate jack from the digital-in USB jack, in order to lessen USB bus power noise. The Mojo will charge off any power source at least 1 amp, and takes 4 hours to fully charge. Plugging in the Mojo to a higher output power source like a larger Anker external battery does not seem to speed up the charging time, so Chord likely limits the Mojo to a 1 amp input maximum; no quick charging here. Judging from the time it takes at a presumably 1 amp input limit, I would hazard a guess to say the Mojo has anywhere from a 3,000-4,000 mAh battery. This means it takes a while to charge the Mojo, but a 1 amp input limit is probably meant to save the longevity of the lithium polymer battery, which is a technology that is susceptible to degradation of life extreme heat. The Mojo never became hot enough to cause me any alarm, though. The Mojo has no problem being charged from a variety of Micro USB cables and external batteries, so the mobile user who likes to use an external battery to charge their devices will be happy here.
 
 
Connecting to the iPhone:
 
In a previous post comparing the Mojo to the OPPO HA-2SE, I was rather a bit harsh toward the Mojo for its pairing to the iPhone. Allow me to be a bit more nuanced here.
 
The Mojo, does not have a USB A input, so you cannot use it with a standard Lightning to USB cable. To connect it to an iPhone, you need to plug the included Micro USB cable into the iPhone CCK USB adaptor, and the Mojo will automatically connect to the iPhone once you turn it on, indicating this by the power/input source marble lighting up red. This pairing is a little less elegant looking, but there are a number of alternatives you can choose.
 
One of them is to connect the iPhone to a Lighting-to-Micro USB OTG-style cable. FiiO makes one called the L19, and it is a short cable that retails for 30 dollars US.
 
If you have bought the Apple CCK Adaptor and Mojo Cable Accessories kit, then you can use the USB Adaptor module that comes with the accessories. This unit basically is a module that plugs into the 4 digital connection slots of the Mojo, extending the length of the Mojo to about the same length as the iPhone 6/6s/7, and replacing the USB digital input with a recessed USB A male slot. This slot is perfectly drilled out for you to plug in the CCK Adaptor, and now you have a fairly streamlined device to strap to your iPhone. The Module still has rubber feet, much like the Mojo, and still has a USB charge port and battery indicator light. My only complaint is that it is made from plastic, and not metal. Also, keep in mind that the Micro USB to female USB adaptor that comes with the accessories does not fit into the adaptor module as snugly as the CCK does, so there is a bit of wiggling.
 
The Mojo does pick up signal antenna noise if is connected to a smartphone and in close proximity to the phone. A solution to this is to switch the phone to Airplane mode, in order to disable these antennas. If you use Pandora, Spotify, or Google Music, then run your smartphone from a Wifi signal. I wish the Mojo did not have this problem, but unfortunately there are technological limits with USB connection technology.
 
This is what the Mojo looks like while it is connected to an iPhone 7.
 

 

 
 
 
AND FINALLY, THE SOUND
 
This is the best way to describe the Mojo: relentlessly detailed, yet beautifully polished.
 
The Mojo has an overall slightly warm, while neutral and powerful sound. While the sound may not immediately pop out at you because of the slightly warmish tint, the minute you listen to brighter, less detailed and refined DACs, you will appreciate the sound of the Mojo. Compared to an OPPO HA-2SE, the Mojo may sound less sparkly and less open, but this is not a bad thing. Because firstly, from my perspective, it is better to have a slightly dark system than a slightly bright system. More often than not, a brighter amp can make bright headphones overly bright and harsh to listen to. The Mojo’s sound signature never clashes or makes a bright or picky headphone sound harsh. You can run it on the pickiest and most unforgiving of headphones, and it won’t sound harsh, nor will it sound distant. This is because the Mojo does not have to restrain its vocals and treble in order to sound detailed or engaging. They are present and are unstressed on their own. This is where a naturally detailed DAC and a refined amp section come into their stride. Soundstage may seem a little more intimate than some other DACs that are brighter, but by no means does this equal a constricted or inaccurate imaging, because imaging is excellent. Bass is also a strong suit, with plenty of quickness and thud when you need it, while staying unobtrusive when you do not. The DAC is 32 bit and has a maximum sampling rate of 768k on USB, and supports DSD 256. S/PDIF has a maximum of 32 bit 192 kHz.
 
To give you all an idea about this flexibility, I auditioned a Mojo at my local hifi audio store here in Chicago. I listened to two headphones on the Mojo: the Sennheiser HD800 and its newest sibling, the HD800S. The Sennheiser HD800 is notorious for being a relentlessly unforgiving headphone when it is not amplified right, or when it is plugged into an insufficiently powerful, dry, harsh or bright amplifier. This usually entails spending much more than the HD800’s value on its own just to get a suitable DAC and headphone amplifier. And often this will mean getting two different devices that are only meant for desktop use. One would think the picky, 300-ohm impedance of the HD800 would bring the tiny, battery-powered Mojo to its knees, but not so. The Mojo tames the dragon that is the HD800, and not only does it do that, it makes the HD800 absolutely sing. This is how the HD800 should sound: musical, unstressed and full bodied. No, the Mojo will not give the absolute best performance to the HD800 like a more expensive desktop balanced headphone amplifier, such as the Eddie Current Balancing Act or Woo Audio WA22, will do, but it is darned impressive on its own. Having a Mojo is more than enough to give a satisfying sound experience to the HD800 that will not make you think you are serving the HD800 an injustice by feeding it from an insufficient source. If you have an HD800 and you do not want to sell your other kidney to buy a good amplifier and DAC, then consider getting the Mojo. The HD800S is the same story, but it sounds even better than the HD800 to my ears, and takes on a brilliant sense of musicality with the Mojo.
 
 
Audio-Technica ATH-M50:
 
Now I've had my M50s since 2012, and I have never liked them then and I still do not like them to this day. I thought they are harsh, grating headphones with an obnoxious, spikey, rough, grainy treble; recessed and dull mids, and a muddy and loose bass. I thought that nothing would make the M50s sound listenable, and the Mojo proved me wrong. The Mojo improved the M50s, and I mean a night-and-day difference. The treble was cleaned up considerably, the bass became tighter with better impact, and the mids became more pleasurable. That is something I have noticed about the Mojo: the ability to sound great regardless of the headphone.
 
AKGs:
 
One of the most source-unforgiving headphone model ranges from my experience is the AKG K7-series. Their dry, lean bass, combined with their often shouty upper-mid-to-lower-treble frequency boost makes them sound dull and at times incredibly harsh and obnoxious on many otherwise good-sounding DACs and amps that have a hint of brightness or lack of refinement. The Mojo, once again, comes into its stride, pairing beautifully with my K712 Pros.
 
In more ways than not, the Mojo’s sound signature reminds me of another British digital audio product: The Meridian Audio Director (Direct DAC), only with its own amplifier stage, and with a better detailed and smoother sound.
 
Conclusion:
 
While not cheap, the Mojo is absolutely a top-flight, world-class audio product, and easily the best portable DAC/amp on the market right now. There are little to no compromises you need to make, and the Mojo can pretty much power anything you plug in into, except for maybe the most power-hungry planar magnetic headphone. If you are looking at an all-in-one device that can drive IEMs and full-size headphones alike, while playing double duty as a desktop amplifier or DAC, and a hifi portable system on the go, then look no further than the Chord Mojo. And now that Chord has just come out with the Poly, which is a module that supports wireless streaming from a source device, and can store songs on its own SD card expansion slot, you can have a modular, truly all-in-one hifi system that will fit into your pocket. 

Allow me to preface this review with some background information.
 
I have experience listening to different present-day AKGs, including the Q701 Quincy Jones Signature, the K702 65th Anniversary Edition (Austrian-made), the K7XX Massdrop First Edition, the K240 Studio, and the K612 Pro. The K7-Series, while highly detailed and comfortable, proved to be a mixed bag for me sonically, with the models being either too intimate sounding, too mid-forward, or too dark. I did believe that these flaws belied a truly great-sounding headphone lurking beneath, but it was simply a matter of sorting out the right acoustic balance. And now I can say for sure that the K712 Pro hits the mark dead on for me, and has become my new favorite neutral open-back headphone. Now onto the review.
 
Build and Finish:
 
The K712 Pro resembles the K702 65th Anniversary (Annie) in many ways, from the charcoal-colored matte plastic body, to the colored stitching on the smooth (no bumps) headband, and the colored center ring on the driver housing. But this time it is in a deep orange color accent theme, with the twin headband rails, headstrap stitching, inner driver ring, and cable being orange, rather than the electric blue of the K702 Annie. Some people might not like this color scheme, but I think it stands out nicely, if looking somewhat like it was themed after a KTM motorcycle (coincidentally another Austria-based company). The K712 is well made, but it does feel a little more plasticy than something like a Sennheiser HD600 or HD650, and certainly more than a Beyerdynamic DT880 and DT990. 
 
The K712 is made in two different places: formerly Vienna, Austria; and presently, Bratislava, Slovakia. AKG users have bemoaned this now complete abandonment of Austrian manufacturing of AKGs, but with the Slovak-made models, you still have a headphone assembled in the European Union. The Austrian-made models like mine have "Made in Austria" silk screened on the center driver cover, while the Slovak models do not have any country-of-origin markings. While I cannot comment about sound or build quality differences between K712s made east and west of the River Danube, those who may want a potential collector's item should opt for an Austrian-made model. 
 
What it comes with:
 
The K712 Pro comes with two cables: a 3-metre straight cable, and a 3-meter black corded cable for plugging into mixing consoles. Also included is a satin-lined black velour carrying bag, which other K7s do not feature, so you get a little more for your money with the K712. 
 
Comfort: 
 
The K712 Pro features AKG's tried-and-true self-adjusting headband, which features a leather strap suspended by elastic bands. It makes the K712 a highly comfortable headphone, in addition to its moderate weight, but the bad part of this is that the elastic bands will begin to weaken over time and lose their tension. This will cause the headphone and the ear pads to slide down your head over time, and it also means the headphone will not sit firmly on the head. So far as I can tell, the solution to this is either to send the headphone into AKG for an elastic replacement, or perform a DIY fix. 
 
The ear pads on the K712 are thicker than the older K702 Annie pads, but are not as thick as the K701, K702 and Q701 pads, and are not angled. Despite this, the K712 retains its spacious ear cups, with the padding made from dense memory foam that conforms nicely to the shape of your head to form a comfortable seal. If you wear thin-armed glasses, then you should have no problem wearing the K712. My ears are notorious for have a problem with rubbing up against driver covers, or getting irritated from having the backs of pads rub against them. With the K712, neither of these comfort issues are present, especially considering the moderate clamping force, and the pads that do not collapse like Sennheiser HD650 and Beyerdynamic DT880 and 990 pads often do. The earpads also run fairly cool for my ears.
 
Sound:
 
Now this is where we get into the most important distinguishing feature of the K712...
 
As I mentioned earlier, I have not found all of the K7-series headphones to be the most satisfying to listen to. The Q701 was extremely spacious sounding to my ears, but I found its overly left-right-panned soundstage to be unnatural at times with older stereo recordings, causing all of the music to go in either direction, and making the center image go dead. In addition, I hated the upper midrange hump, which caused horns and saxophones to trigger an immediate cringe from me. So I thought the soundstage and glare needed addressing. Next I owned the K702 Annie. The Annie was a significant departure from the Q701, with what sounded like a large amount of dampening added to it. Instead of the overly-panned soundstage, the Annie now sounded closed in and highly intimate, the treble was significantly darkened, and there was a slight boost in the midbass (the Q701 had good bass extension though). But there was still that funky upper midrange bump that still stood out relative to other frequencies, especially since the treble was decreased and the bass was increased. The pads also did not have quite enough depth, causing my ears to touch the drivers. So next I tried the K7XX, which was a Chinese-made 200-dollar K702 Annie, but with deeper earpads, and a more toned-down upper midrange. Unfortunately for some reason, this combination managed to end up soundnig dull and lifeless, which spoiled that AKG magic. So finally I tried the K712. 
 
To my ears, the K712 combines a mix between the K702 Annie and the regular K702 or Q701. The headphone overall has an unstressed, fairly musical sound with an overall even tone, and a slight emphasis on the upper midrange and treble. There still is that upper midrange peak at around 1-2,000 Hz, but this time it meshes better with other frequencies since the bass and treble are more even with one another, so the balance ends up sounding less harsh and more neutral, while allowing that presence region boost to contribute to a more musical and engaging sound. The K712 still has that upper midrange increase but just a better tuning of it. Soundstage is great for a headphone of its type, and is the most evenly balanced of any K7 model. It does not pan excessively to the left and right like a K701, K702 or Q701, and it does not sound compressed like a K702 Annie can sound. It has plenty of depth, while imaging and placing instruments accurately. It will not sound out of your head like a Sennheiser HD800, AKG K812, or Sony MDR-MA900 will, but it has better imaging than a Sennheiser HD650, which while being deep sounding can sound blobby with the placement of instruments, and often sounds like a HD600 with simply more depth added. 
 
Treble:
 
The treble on the K712 rarely gets harsh, but could possibly sound sibilant with excessively treble-heavy music (even an HD650 can sound sibilant in the right scenario). There is air in the treble, but overall it sounds mostly neutral. In comparison, the K712 is brighter than an HD650 but much less bright than a Beyer DT990. The K712 sounds great with jazz, acoustic and classical, since the treble has smooth presentation, and contributes to good instrument placement. 
 
Midrange:
 
The Midrange is where the K712 gets into its stride. The midrange has plenty of detail, and rarely sounds stressed. The K712 sounds more musical than you would imagine, and it does not have a bright or overly warm tone that distracts the listener from enjoying a realistic-sounding song. The midrange to my ears is about as realistic and even as you are going to get in an open back headphone for 500 dollars or less. It makes the K712 much more enjoyable than the Q701, which can be irritating, and the K7XX, which can be overly dull. 
 
The bass on the K712 Pro is as neutral as it is going to get on a K7. There is plenty of extension down low, with excellent tightness and a clean tone that makes it easy to distinguish notes. In comparison to the HD650 the bass on the K712 is much less warm, and has a tighter sound, with often better extension. The HD650, especially when underamplified, can overly warm in the bass, and that bass tends to contribute to a pleasing and euphonic sound, but at times can get in the way of hearing finer details. While the K712 has a neutral to somewhat leaner physical bass impact at times, with a good amplifier and a good DAC, it can take an EQ boost, and you can get some good performance with bassy music. That said, the K712 only becomes bassy if the sound it is playing is highly bassy; it does not introduce a bass boost if it does not need to. 
 
K712 Pro vs. K702 Annie
 
Now just to clarify this, the K712 is NOT a rebranded K702 Annie. The two headphones sound noticeably different, though I have heard some newer Annies have been retuned to more closely resemble the K712 sound. Compared to the original Annie, the K712 sounds more spacious in the soundstage, a tiny bit lighter in the bass, and more lively with a more present treble and a more proportionally-balanced upper midrange. To my ears the K712 is better balanced than the K702 Annie, and less dark. 
 
Amplification:
 
First off, do not expect the K712 to sound great plugged directly into an iPhone, iPad or iPod Touch, because it will not. You are going to need to budget in a good amplifier and DAC if you want to enjoy the most this headphone has to offer.
 
The K712 tends to exhibit the same characteristics that are present on other K7s when it comes to amplification: harsh and thin sounding when underpowered or driven on a bright amplifier, dull when not driven on the right source, and revealing of cheap quality DACs. The K712 has a tendency to be less forgiving with poor amp/DAC matches, and often sounds like what you plug it into-to an extent. 
 
I have driven the K712 on the Schiit Audio Lyr 2 hybrid tube/solid state headphone amplifier, and the pairing produces good results, with a tight and unstressed sound, though the stock tubes are a little dull. The Schiit Modi tends to not be a very good source DAC with the K712, as it often sucks a ton of bass impact out of most headphones, and sounds compressed, so I would look at a better quality DAC, or one with a better sound, like an HRT Music Streamer, or Meridian Audio Director. A good sounding and detailed DAC is crucial to the K712, so make sure not to overlook that requirement. 
 
I have heard of people running the K712 off of OTL tube amps like a Darkvoice 336SE, and achieving pleasing results, but do keep in mind that an OTL amp like the Darkvoice or Bottlehead Crack is not going to be the best for impedance matching, as the K712 has a fairly low impedance of 62 ohms, and that impedance tends to stay dead even throughout the frequency spectrum, unlike the Sennheiser HD650. So either a hybrid amp like the Schiit Vali 2, Lyr 2 or Mjolnir 2, or an OTC amp like the Woo Audio WA6 or WA7 would likely be the better option if you choose to run the K712 on a tube-based system. Solid state amps are an excellent choice with their lower distortion figures, lower noice floor and lower output impedance than most tube amps. 
 
As for being driven on a 2-in-1 portable DAC and amp unit, I have been experimenting with both the new Oppo Digital HA-2SE, and the famed Chord Electronics Mojo, costing USD $300 and $600, respectively.
 
The HA2-SE uses the newer ESS Sabre ES9028Q2M DAC chip, which Oppo claims provides a quieter noise floor than the previous Sabre chip in the HA-2. While I do not have the two to compare, I can say that the HA2-SE makes for a very good pairing with the K712 Pro, extracting a good amount of detail, while driving the K712 loud and maintaining a tight and spacious sound. Some people do not like Sabre-based DACs because of their harshness in the upper midrange and lower treble, known as the "Sabre Glare". I do notice some Sabre Glare on the HA2-SE but it does not prove to be a deal breaker, though this glare does not always bode well with the upper midrange emphasis on the K712, and can make the K712 occasionally shouty or blare sometimes. This does not dissuade me from recommending the K712 with the HA-2SE. They make for a pairing that is a great deal enjoyable, and the bass boost switch on the Oppo can add a nice rumble to the K712 when your music calls for it. 
 
But the winner so far is the Chord Mojo. The Chord Mojo is twice the price of the HA2-SE, but handles the K712 excellently, and it should. There is no lack of power and performance, and while the Mojo does not necessarily sound quite as spacious as the HA2-SE on the K712, it makes the headphone sound less stressed and more effortless, with more detailed bass and better imaging, and a less bright tone. That said, the Mojo is considerably more expensive than a K712, so if you cannot justify purchasing it, I can absolutely recommend the K712 with the HA2-SE. 
 
That concludes my review of the K712. Thank you for reading this lengthy writeup, and if you are in the 300-500 dollar market for a neutral open back headphone, and are willing to give an AKG a try, I can safely recommend the K712 Pro. If you like transparent and neutral-sounding headphones, and want a lighter-feeling headphone with more soundstage than an HD600, and a less metallic sound than a DT880 or DT990, then I do not think you will go wrong with the AKG K712 Pro.

I recently had the honor of fostering a mid-production pair of bass-light Sony MDR-R10s in my home for a few days before sending them to my friend overseas. While I wasn't able to listen to them for an extremely prolonged time, I did have some time to listen to them with my system and with my own music. And I'm delighted to say that this headphone indeed lived up to its hype of being a dynamic legend. 
 
A Brief History
 
The Sony MDR-R10 was conceived and designed as a sort of halo model or flagship product from Sony and its designer, Koji Nageno. The headphone was first unveiled in 1989, and production continued until the 1990s, with a total production run of 2000 units. There were a few iterations of the R10, notably a bass-light and a bass-heavy model. I listened to the bass-light mid-production model made sometime around the very early 1990s. The original cost was $2,500, which when calculated to today's money after inflation, is a little under $5000 dollars. 
 
Packaging
 
Being a flagship headphone, the R10 comes with its own vinyl (or possibly leather) suitcase with two lockable spring-opening clasps. The inner lining of the box is a red carpet-esque crushed velvet, with a jewelry box-like compartment to store the cable and a few accessories. Inside the box is a metal plaque with the Sony MDR-R10 moniker stamped into it. This is a serious case for a seriously expensive headphone.
 

 
 

 
 
Build
 
The MDR-R10's design, build and materials make it a true work of art; most other headphones feel like plastic toys in comparison. The headphones with the cable included weigh about 1 pound, or a little over 400 grams. The bales and structure are made from magnesium alloy, and the pully-tensioned headband hammock and earpads are made from Greek lambskin. The inner structure of the headband is made from a shape memory alloy. The cable is double sided, ten feet long, terminated to a 1/4 inch stereo plug (with the classic Sony green poles) and is made from oxygen-free copper with a silicon inner coating and double-woven silk outer skin (meant for strength and lessening static electricity buildup in colder, dry climates). Most notable, however, are the wood earcups. They were the first earcups designed by 3D modeling, and were harvested from a 200-year-old Japanese elm (Zelkova) tree. When you see the cups you will notice they have a matte sheen, a light orange finish, and if tapped, sound hollow or almost plastic-like. This is due to the resonant properties and rigidity of the wood, as it was harvested during the winters in Japan when the trees contracted the most to rid themselves of excess moisture from sap. This tight wood pattern is evident when you closely view the cups, and the tightness maximizes the resonant properties of the Japanese elm. Also note the shape of the cups. Rather than being simply half sphere, the cups have a flat back surface, and the backs are angled away from the ears to optimize sound, along with the angled drivers.
 

 
 
 
 


 
 

 

 
 
 
The wood cups are more than just a cosmetic piece. The designers meant for the wood cups to serve act as acoustic chambers, rather than relying on an open back design. This was truly an innovative headphone, particularly among the closed back section. The R10's innovation in use of wood for acoustic purposes doubtlessly inspired Denon's AH-D5000 and D7000, Fostex's TH600 and TH900, and Audio-Technica's wood headphones. 
 
The drivers used are biocellulose, which unlike mylar, do not suffer from the same issues of harmonic distortion and modal breakup. Despite using an organic, bacteria-based material, the drivers remain in excellent running order and show no signs of deterioration.
 
What I especially like is the lack of tacky badging all over the headphone: just the model name in small letters on the metal cable y-splitter, the word Sony engraved on the metal bales, and the model number and word Japan etched on the inside of the band. It's very much like a Bentley or a Rolls-Royce: no excessive badging needed to announce its presence.
 
If car analogies are fair, the Sennheiser HD800S feels like a 2016 Porsche 911 GT3 RS, while the Sony MDR-R10 feels like a 1963 Ferrari 250 GTO. 
 
Comfort and Isolation/ Sound Leakage
 
The R10 was designed to be a flagship headphone, and thankfully the comfort is also flagship worthy. The R10s are probably the most comfortable headphones I have ever put on my head. I have big ears, and while the earcups are shallow, the pads are broad in surface area to distribute the clamp across the side of my head evenly, are soft, and are angled to provide additional space. I noticed my left ear did slightly touch the soft screen lining of the left earcup, but this was no problem. No clamping aches, no jaw pain, and no migraine-inducing temple pressure to be felt here. The weight of the headphone is slightly more than some more modern headphones like the Sennheiser HD650, but the design is so wonderfully balanced, the R10s stayed put on my head while showing no front or back heaviness, and with little clamping force needed. The headband cradle is simply icing on the comfort cake, distributing the weight across the top of my skull with ease and no pressure to be felt on the ridge of my head. 
 
While it is a closed back headphone, the R10 exhibits little to no sound blockage, and has a modest amount of sound leakage. So don't expect it to be a portable headphone; this is an at-home-only headphone. 
 
Sound
 
When I plugged the R10 into my Schiit Audio Lyr 2 hybrid amp (sadly I didn't have flagship gear to play with), I just heard music. The R10s didn't sound all that painstakingly detailed like a Sennheiser HD800 or Stax SR-009 would sound, and they didn't have the speaker-like bass impact (in fact they might sound a little shy compared to newer headphone) like people associate with Audeze headphones. They sounded like music. These headphones do not jump out at you with obvious detail or big soundstage or bottomless bass. But then it dawned on me what was so special about the R10s: what I did NOT hear. I didn't hear grain or stridence, literally NOTHING. There isn't a single microscopic bit of graininess to be found in the R10/s sound. The treble while detailed did not sound in the least bit hyped, artificial or elevated. It just sounded like treble, but it wasn't rolled off, dark or veiled either. It is beautifully effortless and unstressed treble that lets you hear the tone and detail, but never sounds sibilant or irritating in the slightest. It was easily the best treble I have ever heard on a headphone. Just so dead neutral. 
 
The bass on this bass-light model did sound a little lean and was not ideal with artificial or hyped synthetic bass like you will hear on most of today's Top 40 or dance music. But listening to some good quality electronica such as Thievery Corporation or some jazz rap from A Tribe Called Quest showed the R10 capable of delivering beautifully clear, musical, if not a little lean at times, bass. Again, while not nearly the biggest quantity of bass I have heard on a headphone, the tonality of the bass was outstanding with the right music, and was stupendously accurate when the song was mastered well. 
 
The wood earcups serve as acoustic chambers, creating a somewhat intimate, but neither congested nor diffuse-sounding image and soundstage. The soundstage of the R10 is somewhat similar to a home summit-fi speaker system in how it is presented. While it isn't going to sound obviously airy and expansive like a Sennheiser HD800 or AKG K1000, the R10 does not disappoint, sounding wonderfully personal when I listened to it, and about as close to being at a live performance as I could be
 
But the crown jewel of the R10 is the midrange. You buy the R10 for the midrange over anything else, because to me, this is the greatest midrange I have ever heard on any headphone or speaker system, and will probably never be surpassed in my opinion. So many headphones have a tone to singers and mids that so often sounds like listening to electricity and equipment piping the sound of someone singing to you. In other words, the experience sounds slightly removed or a little uninvolved, and takes away the magic of being there to hear the singer's emotions he/she conveys. That's where the R10 comes in, because I have never in my life heard a more tonally realistic headphone for vocals and mids. Listening to the R10 doesn't sound like a speaker playing Eric Clapton singing Tears in Heaven, it IS Eric Clapton singing Tears in Heaven, complete with the somber, pained emotions he felt when writing and performing the song. It's this soulful, intangible experience that frequency charts or scientific explanations just cannot fully explain. You listen to the R10 with your heart, not your brain, and you don't try to measure it, because thinking or trying to rationalize it will likely leave you scratching your head or even dismissing it. That is why I call the R10 a Stradivarius. There is just something there that people just haven't been able to objectively quantify or explain why it sounds the way it does. While the R10 isn't the last word in perceived detail, that is OK. Because you do not listen to artists perform live and hear their performance analytically or with an aural microscope. You listen with your heart. And that is what the R10s do flawlessly.
 
 
 
Now for the biggest negative about the MDR-R10...
 
I listened to it. 
 
 
With prices reaching in the astronomic thousands, and few people wanting to let theirs go, I don't think I will ever be able to own an R10, even when/if I have the big dollars in the future. And it makes me sad to see that I may never be able to experience this wonderful time I spent with R10s I can call my own. But I am truly delighted to know that I was able to listen to the best of the best, and know that there will likely never be a better sounding headphone I will listen to in my life. And it is reassuring, because I know I have experienced the Nirvana (the Dharmic nirvana, not the band) of headphones, and know now there is no need to lust for something more or attempt to strive for something I think may be greater. This puts an end to the chapter in my headphone-addicted life of wanting to lust after the most realistic sounding headphone. Though I may never again experience such a beautifully emotional and transparent headphone like the R10 again, I am delighted to know that I had the experience. I caught the magic dragon, but then had to bid him farewell and let him run free. To have a beautiful experience and come to terms with the emotional feeling of never having it again is still better than never having the experience in the first place and wondering what the fuss was all about. While I bid farewell to the Sony MDR-R10s, I can now put to rest the yearning for something better, and come to terms with knowing I may never again have that personal listening nirvana.
 
 
Thank you all for your time, and have a wonderful day. 

Background

After owning the HD650, I found that at times on my system, there was a little too much thickness and darkness. So I wanted to try another Sennheiser that had more forwardness to the treble and mids, and was leaning more toward the neutral side. I also didn't want a bright headphone; I usually hate bright headphones, as they give me stabbing pain in my ears. I prefer the smoothness of Sennheisers, even if they lack a little excitement for certain moods.

The HD580 Precision was released somewhere around 1991, and it marked a change in direction for the sound of audiophile headphones. Headphones during the late 80s to early 1990s were generally treble forward and not highly present in the bass region. This was especially true for German headphones of this time period. My experience from owning the MB Quart (German Maestro) QP220, and the less expensive sibling to the HD580, the HD545 Reference, seems to have confirmed this. Those headphones were quite loose fitting and very comfortable, but their treble was exaggerated and their bass lacked tightness and extension. In short, they sounded too top heavy. The HD580 departed from this trend, and had what many other similar headphones, as well as similar-aged Sennheisers didn't have: a well extended sound without uneven exaggerations. This brought the HD580 to the attention of many audiophile circles and magazines, long before Head-Fi was founded, and it soon developed a fanbase. The HD580 was a game changer in the dynamic audiophile world. I noticed that most of the people who invoke the term "Sennheiser Veil" do not usually cite the HD580 as an example, but instead the HD600, and more often, the HD650 (I'll dive into this later in my review).


Build and Form Factor

Build-wise, the HD580 is the older brother to the HD600 and HD650, and most of the parts between the three headphones are interchangeable. The highly overpriced earpads are the same, though the HD580's original earpads are said to be a little thicker than the 600 and 650 pads. The padding on the headband is the same 4-bump design as the HD600, and the thin dual sided cable that terminates to a 3.5 mm jack with a 6.3 mm stereo sleeve plug is also the same as the HD600. As aesthetics go, whereas the HD600 has a blue granite plastic finish with lacquer and HD650 a graphite and sparkled finish with lacquer, the HD600 has a blueish-gray satin finish on the headband, and black bales with no lacquer. The ear capsule grills instead of mesh metal are color coded plastic with houndstooth-looking patterns. These grills aren't exactly as pretty looking as their mesh contemporaries, but add a quaintness to the HD580 that I personally like. However, if you so wish, you can change out the grills for 600 ones.

A problem with the HD580 and some HD600s is the spring tensioners that make contact with the positive and negative terminals on the plugs, which carry the signals to the voice coils. Over time, especially with repeated removal and reattachment of the cable, these springs lose their tension and fail to touch the plugs, causing the sound to cut in and out. My HD580 does not suffer from this problem thankfully, but that is something to watch out for when shopping for used HD580s on Ebay or other sites. Make sure to ask the seller if they experience sound cutting out when wiggling the jacks, or if it was a problem, have the voice coil connector springs been replaced.

Another issue with the HD580 is simply due to the age of the headphone and the amount of time people have owned theirs. The headband padding and earpads tend to go flat and need replacement. I haven't seen a single HD580 for sale on eBay (other than unused NOS ones) that didn't have a flat headband and earpads. So when you purchase the HD580, new pads are a cost you need to take into account. I purchased an aftermarket HD600 headband from a retailer in China for under 3 US dollars, and it is almost indistinguishable from the real deal. So there is 17 dollars saved. HD600/650 earpads will work, but unfortunately they do not come cheap. About 60-70 dollars, maybe a little less if you can order them directly from Sennheiser. I found that aftermarket earpads aren't as good when it comes to thickness and build, and using Brainwavz earpads can make the bass too strong and shelve off the mids too much. So I don't recommend cheaping out too much here.

Fortunately, earpad wear shouldn't be as fast on the HD580 as the HD600 and HD650, due to the fact that the 580's headband is a wider shape, and as a result it clamps quite a bit less. You can see in the picture below. The HD580 is on the left and HD650 on the right.







Now, onto the sound.

I haven't heard the HD600, but I do own the HD580 and HD650, and from what I read, the HD580 is the neutral of the three, the HD650 warmest, and HD600 the halfway compromise between the 580 and 650. Or to a 600 fan, the 580 is the brightest, the 600 neutral, and 650 darkest. My references to the HD600 are based on numerous conversations with trusted audiophiles.


Treble

The HD580's treble varies on how the pads fit around your ears, but without a good seal, it sounds peaky and thin. With a good seal however, the HD580 to my ears sounds well controlled and smooth, with good upper treble detail in guitars, triangles and cymbals. There is a bit of an emphasis around 7-8 kHz, and on brighter systems this can sound more apparent, but it is what I would call sibilant or metallic, It is just somewhat emphasized. The HD580 has a treble cleanliness that I haven't heard often. Relistening to well-known songs produces cymbals off to the left and to the right crashing or ringing out, something I haven't heard before on the track and something that often gets masked over with the HD650. The HD580 does this while not being ear piercing or underemphasizing the treble, an excellent balancing act that may new headphones do not seem capable of doing. They either recess the mid treble and hype the upper treble, which gives a grainy and uneven sound; or they overemphasize the treble to give people the impression of detail, which more often than not sounds metallic and artificial.


Mids

The mids to my ears have an even and coherent presentation to them. They neither feel veiled, nor are they emphasized relative to the treble and bass. This isn't a mid-forward headphone. Compared to the HD650, the upper mids aren't darkened to mute out shoutiness, and the lower mids aren't tuned to sound richer. The HD580 can do female and male vocals equally well, and vocals and mids have an equally front and center feel. If there is any complaint I may have, it might be that the mids aren't inherently lush sounding like they may be on the HD600, and certainly less than the HD650, but the HD580 isn't dry or raw sounding. This is a headphone that can play rock and opera music equally well. The HD580 feels like the sort of headphone that you don't have to cut through distracting emphases in the treble or bass to achieve that correct tonality. Beyerdynamic DT880 fans might still feel the HD580 veils some energy and details, and AKG K702 fan may not get that biting rawness to the mids they
enjoy, but for the average person, the HD580 is a great sounding midrange headphone.

Bass

Bass on the HD580 has a very slightly wooden or swelling sound to it (Sennheiser house sound), but never gets bloomy like the HD650 can be. It remains tight and controlled from the upper bass to the sub bass, and as for that sub bass.....yep, it ACTUALLY has sub bass extension. Something people often complain the HD600 doesn't have. I'd say due to the fact that the bass is tighter, it has a better audible extension than the HD600 or HD650. Often the warmth has to be cut through on amplification to make the sub bass noticeable. The HD580's bass is neutral with just the right sounding tonality to it. What I enjoy is how versatile the HD580's bass is, with enough impact to sound right with trance, house music, and may I even say some hip-hop? Maybe, but if you listen to electronic music predominantly, I'd recommend the HD650 more, due to its stronger mid bass.

Soundstage

The HD580's soundstage is comparable to the HD600's, i.e. sounding more "around your head" than if it was coming from all directions. Still, it is acceptably open, without being the least bit cupped-hands sounding, hollow or "in your head". Neither does it sound diffuse. As for classical music, the HD580 sounds best with string-emphasized sections or chamber orchestras. In other words, classical music that doesn't rely as much on depth and layering to convey the right sound. Where the HD650 pulls ahead of the HD580 is in depth and layering of the soundstage, which makes it a better choice for horn sections, and full symphonies with greater range of instruments. The HD580's true forté is in acoustic guitar genres like flamenco and jazz, where depth and layering isn't as important as quickness in the mids and treble.

Amplification

My system consists of the Schiit Audio Modi USB DAC, and the Lyr 2 hybrid tube and solid state headphone amplifier. While my DAC definitely needs upgrading, the Lyr 2 is a good paring with the HD580, bringing out plenty of sub bass and mid bass, while keeping the midrange neutral and clean, and the treble behaved. The Lyr 2 is great for its solid sound in the bass and its solid state midrange, but for those of you who would prefer a tubey-sounding midrange and do not require a ton of bass extension and impact, there are a couple of other choices. The HD580's impedance is 300 ohms, which means it plays well with output transformer-less (OTL) tube amplifiers. Good pairings include the Bottlehead Crack, the Little Dot MK II and MK IV, and for more money another excellent choice is the Woo Audio WA3. The transformer coupled Woo Audio WA6 is also said to be a great choice. There are plenty of different headphone amplifier options for the HD580, and since the HD580 is quite neutral, it is easier to fine tune the sound the way you want with your gear. You can choose to have a drier sound with solid state amplification, a lusher sound with all-tube amps, or have a more impactful sound like I have with a hybrid amplifier.

Conclusion

The HD580 is a real ownership joy due to its sound that can still hold its own today among the best mid-tier neutral headphones such as the AKG K702, Beyerdynamic DT880, the new Audio-Techica ATH-R70X, and even Sennheiser's own HD600. Because of its sound and its ease of use with different amplifiers, transducers that are made to last, comfortable fit, and ease of sourcing spare parts and replacing them, the HD580 is a vintage headphone that has none of the usability drawbacks that other cans of similar age do, and still feels as good as it did when it first rolled off the assembly line nearly a quarter of a century ago.

Before the Lyr 2 I owned two hybrid headphone amplifiers: the Hifiman EF2A, and the Maverick Audio A1. What both those entry level amplifiers lacked was the power and sonic dynamics to drive my mid-level headphones to their true potential. They were either too aggressive, or too soft and lush sounding. But due to my variety of both high impedance and low impedance headphones, I wanted to stick to hybrid amplifiers, and simply move up the ladder. I was gifted a Schiit Audio Lyr 2 in December, after deciding between it and the Garage1217 Project Ember. The enclosed case of the Lyr 2 was what won me over. 
 
 
Build quality: 
 
The Lyr 2 uses a brushed aluminum body with recessed slots for the two tubes. It's made by Schiit Audio in California, and comes with a 5 year warranty. As I mentioned, it is a hybrid amplifier, combining both solid state transistors and vacuum tubes. Changes from the Lyr 2 include a gain selector switch, and some sonic changes to give it a more refined sound. The amplifier doesn't feel as finely crafted as say, a Woo Audio amplifier, but also isn't as expensive. The high/low gain selector and power switches are both located on the back of the unit, as are the unbalanced RCA input and preamplifier jacks. I haven't used the Lyr 2 with self-powered speakers, so I cannot comment about its ability as a preamp. But according to Schiit, the Lyr 2 isn't meant to be used as a speaker amplifier, only as a preamplifier to powered speakers. The gain knob is anodized aluminum finished, and has a smooth turning actuation. No steps to be found. It's not very gain-happy so even in high gain it will require you to turn it past 10 o'clock when used with full size power-hungry headphones. This doesn't mean the amp is struggling to output power, it just means that the gain knob isn't extremely sensitive. 
 
 
Heat: 
 
One warning I must give is that the Lyr 2 get bloody hot. Enough to almost burn your fingers. It also tends to heat up the volume knob. So I suggest not running the Lyr 2 if your room is in the heat of summer, or if you don't need a space heater. Make sure to give the Lyr 2 plenty of ventilation and keep dust out of it. 
 
 
Tubes:
 
I was using the stock tubes shipped with the Lyr 2, which are a pair of Canadian 6BZ7s. They are acceptable stock tubes, but I personally don't like them very much. I find them to be too finicky. When they haven't been fully burned in, they tend to suck all the bass out of your headphones and sound rather brittle and bright at times. Once you get past their long burn in time, they are fairly neutral tubes with good extension in the treble, and decent bass. But they take an unnecessarily long time to heat up when turned on from cold. They take about 20-30 minutes before the midrange comes forward and the bass takes impact. Another downside I have with them is that they tend to be microphonic. I find that if they are on for a while, they start to hum, and the humming transmits through lower ohm headphones at high gain. At low gain I don't hear humming. Speaking of gain, the stock tubes are too aggressive sounding with most headphones on high gain. I find that they sound their smoothest on low gain with lower ohm headphones.
 
Fortunately the Lyr 2 uses 6DJ8 (also called the ECC88 and 6922 in Europe, 6N23P in Russia, and 6N11 in China) model tubes, which although not the cheapest in entry price (6AK5s would probably take the medal for that), there are lots of good sounding pairs for sale on eBay with different sound signatures. Ranging from the stock tubes (not recommended) to mid range models such as Amperex, Electro-Harmonix, Voshkod and Mullard tubes; all the way up to 200 dollars for a matched pair of Siemens. So there will surely be a tube right for you.
 
On recommendation from another Head-Fier with a Lyr 2, I recently purchased a pair of vintage 1964 General Electric Red Labels for 50 dollars, and they are a fantastically sweet sounding pair. With lots of dynamics and fullness to the midrange, a detailed treble that still manages to never be harsh, and a full sounding upper bass and mid bass that sounds wonders on the Sennheiser HD650s without being bloated or too full. It's absolutely the perfect sounding tube to me. Its tonality is supremely realistic. But if you want the Lyr 2 to be more airy and faster sounding, an Amperex Orange Globe or Bugle Boy or Electro-Harmonix should be for you. For a dark and solid sound a good pair of Voshkod Rockets should also be for you. And for those of you who have a Woo Audio WA3, which also uses two 6DJ8 tubes, the GE Red Labels if you can find a matched pair like I was lucky to should be a great tube to roll on the WA3, as it is already a smoother sounding amp than the Lyr 2. 
 
 
Now, onto the sound. Overall, I would consider the Lyr 2 to be fast, dynamic, somewhat dry but with some warmth in the bass and mids depending on which tubes you run it on. Here are my impressions with the stock tubes used.
 
 
Treble: The Lyr 2 has that characteristic dynamic, extended and forward yet smooth treble characteristic of Schiit Audio amplifiers. It's a bit north of neutral, with enough energy to bring out the dynamics of darker headphones, but has the refinement to not sound overly aggressive with somewhat brighter headphones. On high gain it becomes rather shouty or metallic, but this may be just due to the tubes, or the DAC. It's not rolled off like a Woo Audio WA6, but also not as bright as a first generation Schiit Valhalla. 
 
Mids: The mids are where the Lyr 2 has more of the characteristic hybrid sound of lying somewhere between dry and fast like a solid state, and being tubey or warm sounding like an all-tube amp. It's neither cold nor flush. The mids have a good fill-in, if slightly mechanical sounding compared to the treble and bass. Nonetheless, the Lyr 2 is where you will start to notice an improvement from entry level amplifiers. It has a revealing and dynamic nature that you don't hear in entry level models. On high gain, the upper mids and lower treble can be a little blarey or shouty with some headphones. The gain selector can often transform the Lyr 2 from being slightly warm to fast and forward. 
 
Bass: The low end is where the Lyr 2 really comes into its stride. It has plenty of impact, great extension, is not muddy, and never gets soft or blobby sounding. It has that great bass speed of a good solid state amplifier while still having the slight warmth that one expects from tubes. Rolling tubes will help change the impact of the bass or its warmth, but regardless, the Lyr 2 itself can bring plenty of bass out of headphones without being artificial.
 
Soundstage: Soundstage has a fair amount of neutrality to it, which once again, depends on your tubes selection. With the stock tubes, the Lyr 2 has great instrument placement, good depth, and on high gain is a little wider. It has more soundstage accuracy than other similarly priced tube amps, but not as much as some solid state amps.
 
Overall, I would say the Lyr 2 is a mix between the speed and cleanliness or the Asgard 2, and the warmth of the Valhalla 2, while having more power than either one. There is simply this sonic sense of a step up from entry level desktop amps to the Lyr 2 in terms of dynamics and physicality, and it has more dynamic punch than the Valhalla 2, at least with the latter's stock tubes. Schiit Audio products are all good performers in their respective price points, but the Lyr 2 is where Schiit starts to sound great. 
 
 
System synergy: Because of its transparency and revealing nature, the Lyr 2 requires a mid-level DAC to sound its best. I currently use the 99 dollar Schiit Modi, and while it might be a great entry level DAC, it is beginning to show its limits with the mid-level Lyr 2 in terms of bass dynamics, soundstage, dynamics and refinement. Many people do not think DACs are as important as an amplifier, but trust me, if your DAC's audio signal isn't up to par, your amplifier isn't going to make it much better sounding. And this is doubly true if your amplifier is revealing like the Lyr 2. Be warned: the Lyr 2 is where system synergy becomes an important factor in getting your music to sound the way you want it to. I was likely going to upgrade to either the HRT Music Streamer II+ or the Music Streamer HD. When I get either one, I will update this review.
 
Headphones I use with the Lyr 2:
 
The headphones I use with the Lyr 2 are my Sennheiser HD650, the AKG K7XX Massdrop Edition, and vintage Sennheiser HD545 Reference.
 
The HD545 I believe is a 300 ohm headphone with a bright and fast treble, a slightly diffuse midrange, and a light and lean bass with still good extension down low. The Lyr 2 adds tightness and extension to the bass, brings out the midrange, and adds extra air and soundstage to the treble without adding aggression. The result is a great pairing that takes the already airy and breathy sound of the HD545 and makes it a pure joy for acoustic and classical music. The HD565 and HD580 should also make a great combination with the Lyr 2 as well. 
 
My HD650 is a 2014 model, which is a bit brighter than the older HD650s. When the tubes are fully warm, the Lyr 2 makes a great combination with the HD650, keeping it fast, bringing more tightness to the bass, and keeping the treble dynamic. The combination works well, and the HD650s sound great on low gain. High gain tends to make them slightly brash. 
 
The K7XX is where a truly great pairing happens. The K7s with their pickiness for a great system are right at home with the Lyr 2. It brings out a level of bass impact, mid range dynamics, and treble smoothness that I have never heard before with the K7-series. On the Lyr 2, I'd say the K7XX surpasses the HD650 in dynamics and a resolving sound. The combination is fantastic and the best I have heard with AKGs thus far.
 
 
That's it for my review. If anyone has any questions pertaining to the Lyr 2, I will try to answer them to the best of my abilities.  


DAC Update: I recently purchased the Meridian Audio Director, and I can confirm that this makes a great pairing with the Lyr 2. The Director has that signature Meridian sound: digital while being layered, warmer and effortlessly smooth, and very hifi-friendly sounding (not cold or analytical). As synergy goes, the Meridian Director kicks the Lyr 2 up a notch, having a source component as equally good sounding as the amplifier. Alternatively, from what I heard of, the Fostex HP-A4 also makes a good DAC to use with the Lyr 2, and because it has its own amp stage, it can be used on the go.

To start this review off, I've owned several AKGs, including the Q701 Quincy Jones, the K702 65th Anniversary, K240 MK II, and until a few months ago, the K612 Pro. I was craving another AKG, and before I pulled the trigger on the pumpkin-colored USD 350-400 K712 Pro, the internet bulk buying site Massdrop announced that they were partnering with AKG to make the special edition K7XX Massdrop Edition. Made in China instead of Austria, I was originally skeptical that AKG was able to hold up their claim that they made a 200 dollar version of their 500 dollar K702 65th Anniversary Edition. I thought it was a needless purchase, since I previously owned an 'Annie and there wouldn't be anything new to refresh my enthusiasm. However after inquiring from another AKG enthusiast, the K7XX would sound different from my former K702 Annie and it was worth a shot.
 
This is where things get a little complicated:
 
My K702 Annie was an early production (EP) model, which predated its mass production younger sibling, the K712 Pro. The EP K702 Annies and K712 Pro do not sound the same due to different tuning and slightly different memory foam padding between the models. The EP K702 Annies have a dark mid and upper treble, a boosted upper mid section, a slightly boosted bass overall from the K702 and Q701, and a fairly closed in soundstage. The K712s have more mid to upper treble, a little extra mid bass emphasis over the Annies, and a more open, wider soundstage. Whereas the EP K702 Annies have an intimate, treble-dark, thick, mid forward sound, the K712 Pros have a somewhat U-shaped sound. HOWEVER, AKG in the later production run of the K702 Annies retuned them to sound more like the K712s, giving them a little more mid treble, warmer bass, less exaggerated upper mids, and a wider soundstage to become a sonic hybrid of the K712 Pro and the EP K702 Annies. This retuned version of the K702 Annie was what AKG based the K7XX on. This wasn't the first time AKG tuned older versions of a headphone to sound more similar to a newer version. When AKG launched the first K7 incarnation, the K701 back in 2006, and later the dark blue K702, they received a number of complaints that the headphones had little to no physicality to the bass, plastic sounding and overly zazzy treble, and no warmth to the mids. When the Q701 Quincy Jones Edition was introduced, AKG soon redesigned and relaunched the K701 and K702, which now sounded like the Q701, having better behaved treble, less diffused soundstage and slightly warmer upper bass. When reviewers state that the K701, K702 and Q701 sound the same, this is because they are listening to the retuned models, and not the colder, brighter earlier versions. 
 
Here are some pictures. Each image belongs to its respective owner. 
 
K701
 
K702
 
Q701
 
K702 Annie
 
K712 Pro
 
Now that I've clarified this potential confusion, onto the review. 
 
The K7XX build-wise is pretty much identical to its K7 siblings, with its large driver capsules, matte finished plastic from the K702 Annie and K712, a single sided detachable cable terminated to a 3 pin mini XLR connector (sorry balanced audio fans, this isn't going to be as easy to run balanced as a Sennheiser HD600/650), and a genuine leather, bump-free headband just like the Annies, K712, and now Chinese made black K702. The K7XX is an all matte black headphone with black ear cups, black cable, and black headband rails. It has a very handsome and stealthy appearance. So if some of you didn't like the black and orange K712 and thought it looked like the headphone incarnation of a KTM motorcycle (also Austrian), or if you crave the headphone equivalent of a black helicopter, the K7XX may be just for you. What's interesting is that the first model of K7s, the K701, was an all-white headphone, while the latest model, the K7XX, is all-black. Maybe this is a sign that the color gamut has ended and this will be the last version of the K7 family? Who knows. The K7XX like the K7s now made in China, doesn't quite have as nice a build as the Austrian and Slovak-made K7s, so there is a bit you give up in build for a cheaper headphone. But not a ton. 
 
So as comfort goes, the K7XX is about as comfortable as a K7 can possibly get. The clamp is enough to keep them on my head without making them a vice grip, the headband is auto adjusting via elastic straps and as I mentioned has zero bumps underneath it to give my skull hot spots. The ear pads are fairly large in size and while the openings are circular and not the largest in diameter to allow long ears to float freely in them, they are plenty deep, never overheat, and have a very luxuious velour wrapping. They are deeper than the K702 Annie pads, which I found weren't deep enough for my ears, causing them to touch the driver covers. Not the case here. The foam padding while firm and super dense, conforms seamlessly to the the head and requires no break in to achieve a seal around the ears. This is some of the best use of memory foam padding I have experienced in a headphone. I expect this padding to keep its compliance and strength for quite some time. While it might seem somewhat firm at first, it disappears over your head.
 
Now onto sound.
 
The K7XX to my ears has a level of refinement, resolution and dynamics that most other 200 dollar open backs simply cannot deliver. For an AKG, it's a slightly warmer and wetter sound, but compared to Sennheisers it still remains a little dry.
 
Soundstage has a good amount of imaging and instrument placement, while not having the tendency to pan left and right, with the center stage going dead like on the K701 and K702. There isn't this level of airiness or diffusion one might expect from an open back, but soundstage by no means is cupped or closed in. 
 
The treble to my ears has great air and extension when the situation calls for it, but otherwise remains neutral and kept in check. When amplified adequately and fed good quality audio, it never goes out of control with splashy or sibilant highs. There is some brightness in the mid treble that becomes apparent on aggressive sounding equipment, but not artificially so. I wouldn't call the K7 dark nor bright, but neutral and right where it needs to be. It has enough treble to be good with shredding guitar solos and high hats on rock, while having enough air for violins and stringed instruments. 
 
The mids on the K7XX have that sightly dry and analytical texture to them, with great speed, detail and presence without sounding brash or shouty in the upper mids like the Q701 often did, especially with women vocalists, saxophones and trumpets. When underamped, the K7XX can sound withdrawn or hollow in the mids. I have no complaints about the mids and vocals. They are exactly where I want them, and they deliver that AKG house sound, while not needing to overboost the lower treble. 
 
The bass on the K7XX is another one of its strong suits. The bass is some of the best resolving and extending, and tightest I have heard of any mid-fi dynamic headphone, and rivals if not beats most equivalent open backs. But this shouldn't be a surprise, as bass tightness and speed is a strong suit on contemporary AKGs when they are amplified right. Where the K7XX doesn't have the most emphasis in is the upper bass to the mid bass, where accentuations in these frequencies give the mids that bloomy, chesty, filled in sound (think Sennheiser HD650 or Shure SRH1540). The upper bass and mid bass, however, still hit and punch when they need to. Kick drums and stringed bass still have plenty of energy. The K7XX can make a great house music and trance headphone. The sub bass is a high point, with excellent low end energy and tightness. The K7XX doesn't have that annoying open back dynamic headphone tendency to dive off a cliff in the sub bass. The K7XX has a surprising amount of rumble to it. Due to its great low end extension, and tight, fast upper to mid bass without a bloat or bloom to slow it down, the K7XX makes a great Drum and Bass headphone. 
 
 
Next up: amplification. 
 
The K7XX like all other K7s is 62 ohms, with an impedance curve that stays astonishingly flat and steady throughout the entire audible sound spectrum, only increasingly slightly in the very upper treble. This is very unusual for a dynamic headphone, and it's something one only sees with planar magnetic headphones like the Hifiman HE400i, HE560, and the Audeze LCD series. This low impedance tends to mislead people to think that it's an easy to drive, efficient dynamic headphone, which it isn't. Many reviews I hear from people saying the K7 series has sibilant treble, hollow mids, and dull bass most often is a result of underamplifying the headphone, or running it on an amplifier that it doesn't like. The K7XX may be a steady 62 ohms of impedance, but it isn't very sensitive and is current hungry. It sounds best on a desktop mains-powered amplifier with a good quality sound card. There are claims that the K7s sound best on an all-solid state amplifier due to its steady power output and its more current output at lower ohms than all tube headphone amplifiers, but if the amp is good enough, the K7XX will sound great regardless of whether it is a tube or solid state amplifier. 
 
My personal rig that I use the K7XX with is the Schiit Audio modi USB DAC, and the Lyr 2 hybrid tube and solid state headphone amplifier, which can output up to 6 watts of power at 32 ohms, with max power decreasing to 330 milliwatts at 600 ohms. It's a great amplifier with the K7XX, delivering tons of power when I need it, though in high gain mode with the stock 6BZ7 Canadian-made tubes becomes a little aggressive in the treble and upper mids. Other good headphone amplifier options include the solid state Burson Audio Conductor and Violectric HPA-V200, and the all-tube OTC Woo Audio WA6 (which according to fellow Head-Fi user Hifiguy528 does a great job driving K7-series models), WA6-SE and WA7 Fireflies. I do not recommend OTL amplifiers like the Schiit Audio Valhalla, Darkvoice 336SE, Bottlehead Crack, and Woo Audio WA3, as their high output impedance and lack of current at lower ohms will not play well with the K7XX. If you go the tube route, then make sure you either get an output transformer coupled (OTC) or hybrid model. Basically the more refined and powerful the amplifier, the more the K7XX will like it. On the cheaper end, the solid state JDS Labs Objective 2 and tube hybrid Schiit Audio Vali will both do an admirable job, with the Vali bringing a little more energy and excitement to the sound than the O2. The K7XX scales up noticeably with equipment, so it can remain a staple in one's headphone fleet, even with upgrades in equipment. 
 
 
Oh, and as for burn in, the K7XX like most other K7's needs 200-300 hours of burn in before it sounds best. If you put it on right out of the box and start listening without any burn in you will be sorely disappointed. Before the 150 hour burn-in mark, the K7XX treble is sibilant, the mids are highly recessed, and the bass lacks weight. Put a good 100-150 hours of burn in on the K7XX before doing any sort of serious listening. After 250-300 hours or so the K7XX will really start to sound as it was intended to.
 
If you made it to the end of this odyssey-like review, I thank you for your time and patience. If desired, I will do a follow review comparing the K7XX to my Sennheiser HD650. Cheers. 

I bought the HD650 after owning a number of equally good headphones, including the Beyerdynamic DT880 Pro, DT990 Pro, AKG K702 65th Anniversary, and AKG K612 Pro. I'd have to say that while the HD650 has many competitors nowadays that it didn't have when it debuted in 2003; especially lower than its MSRP of USD 500, it nonetheless holds its own and still offers qualities that many of them do not offer. 
 
The HD650 is the most recent incarnation of its family of headphones. The basic driver design and headband design as far as I can tell dates back to the late 1980s-early 1990s with the HD545 and HD565. The design takes inspiration from Sennheiser's volume production version of their 16,000 (1991 money) dollar Orpheus HE-90 electrostatic flagship, the HE-60 "Baby Orpheus". In around 1993 Sennheiser launched the HD580 "Precision", in 1995, they launched the HD580 Jubilee Edition to celebrate their 50 year history. It had metal earcup grills instead of plastic ones, McLaren F1-esque carbon fiber furniture, and was sonically identical to the HD600, which was launched the following year in 1996. The HD600 had blueish granite furniture, and a sound comparatively warm and lush for its time while retaining a good level of neutrality. Then in 2003 came the HD650, retaining its position of Sennheiser's flagship headphone until the launch of the technical masterpiece, the HD800. The HD650 and HD600 are still sold together, with retail prices of 500 dollars and 400 dollars, respectively. While the HD600 earned itself the reputation of being the "Veiled Senn" due to its relatively warmer and more relaxed treble compared to similar flagships such as the Beyerdynamic DT990 and AKG K501, the HD650 has arguably been more deserving of the title. The HD650 was known by detractors for having a veiled, dark treble, a compressed soundstage, and a boosted, almost obese sounding mid bass; while the HD600 was the neutral of the two. However in 2010, Sennheiser retuned and updated the drivers on the HD650 to give it a less thick and a more energetic sound. The bass was lowered, the treble was raised, and the soundstage opened a bit more as a result. 2010 updated HD650s can be identified by their silver diaphragm shields, vs the black shields of the 2003 models. My HD650s are a 2014 model with the silver shields, and mine comes in a black black box and updated slip box, whereas the 2003-2013 pre and post retuning HD650s had a silver box and corrugated outer packaging slip box design. According to some unconfirmed rumors, the HD650 was retuned a second time to sound even more neutral for the 2014 model. I previously owned a 2010 HD650 with a silver box, and while there might have been more darkness and a bit more bass in that previous model, I can neither confirm nor deny this, as it may be a placebo or anecdote.
 
Here are some pictures of the 650's family members. The images belong to their respective owners. Just click on the names of the headphones. 
 
HE-60 "Baby Orpheus"
 
HD565 "Ovation" 
 
HD580 "Precision" 
 
HD580 Jubilee
 
HD600 
 
HD650 (black driver)
 
HD650 (silver driver)
 
Build-wise, the HD650 is a timeless and no-frills modular design of mostly plastic and some metal. The outside headband, the bales and the ear cups are plastic, while the inner headband is spring steel and the outside earcup grill is some sort of metal mesh. The headphone can be disassembled by hand to its component parts and basically every part can be purchased from Sennheiser and replaced. That's something you don't see on many headphones today. The dual sided cable is detachable and has two pins for each side, making the headphone easy to run balanced. Just unplug the included cable and plug a balanced one in. The stock cable has decent enough shielding, is dual channeled, is about 10 feet long, and terminates to a 6.35 mm stereo plug with an excellent 6.35 to 3.5 mm adaptor cable that will not put strain on the 3.5 mm output jack of your source device. The cable doesn't tangle easily and doesn't retain kinks. I would have liked the y-splitter to have been a bit lower but that is all I have to complain about. I have not used a Venus Audio or Cardas Canare cable on the HD650, so I can neither confirm nor deny whether they are worth the purchase. My biggest complaint is that replacement ear pads are 60 dollars from Sennheiser, making them very expensive considering they have a tendency to flatten out after a couple of years. There are third party Chinese made ones on eBay for half the price though. 
 
Comfort-wise, I didn't originally like the HD650. I found the spring steel headband, while extremely durable, made it a vice grip on my head, causing a headache. Another side effect of this clamp was that the pressure caused the velour ear pads to prematurely collapse, leading to my ears pressing against the foam driver disks, making them red hot and sore. I find that the HD650 doesn't have deep enough ear pads, and the arey fairly narrow, causing the edges of the pads to rest on the backs of my ears. I found that stretching the headband out (by taking the ear pads off and placing the HD650 over a speaker cabinet overnight) lessened the clamp, and rotating the cup pivots to put more clamp on my temples made the ear pads keep their shape, and now my ears are no longer pressing against the drivers. I find this to be a lot of fiddle work just to make a headphone comfortable enough. Removing the foam driver covers does give a little more depth, though it makes the sound a little brighter. This might be desirable for some people though.
 
Personally I would have liked Sennheiser to have stuffed the HD650 ear pads with a denser material like gel or double memory foam to keep the shape for longer periods of time.
 
The hand band is a nylon-type material and has plenty of padding. There is an indentation in the middle of the pad so you can rest the headphone on a stand and not dent the padding, and for people with a Sagittal rest in the middle of their heads, this can provide a little more comfort as the headband isn't hanging up on the ridge and causing aches from hot spots.  
 
As amplification goes, the Sennheiser HD650 is a headphone like prefers a powerful yet somewhat lush sounding amplifier or tubes on an amplifier. Though it is 300 ohms, the HD650 is quite a sensitive headphone, which means one will not have to crank up the gain on an amplifier to get a satisfying listening level, and will not hear as much amplifier strain. I was able to listen to the HD650 at perfectly satisfying listening levels from the headphone jack on my iPhone 5, and it also sounded good on the FiiO E07K portable amp and DAC I owned. The HD650 is more performance hungry than gain hungry. The better the amp to feed it power, the better it will sound. The HD650 isn't as system-picky as AKG headphones like the K702 or K712 Pro, so it is easier to attain a better sounding synergy with. The HD650 DOES prefer an amp that has a powerful sound to it, so solid state or hybrid amps are more preferable. All-tube amps such as the Woo Audio WA6, WA7 Fireflies and WA6-SE are supposed to sound excellent with the HD650 due to their transparency and power while still being refined. Higher end solid state amps such as the Violectric HPA-V200, Burson Audio Soloist and Conductor, and Meridian Audio Prime are also said to be great with the HD650.
 
I personally use my Schiit Audio Lyr 2, which is a powerful sounding yet thick and refined hybrid headphone amplifier with the HD650s. It still doesn't make them bass cannons or treble monsters, as the HD650 will tend to keep its softer sound regardless, but on low gain it has plenty of power and refinement. On high gain, however, the Lyr 2 becomes a bit too gain happy and aggressive with its stock tubes on the HD650, making the midrange and lower treble too forward and splashy sounding. Low gain is the better setting and is more controlled sounding with the gain-sensitive HD650s.
 
Now for sound: 
 
The HD650 was and still remains unique, as unlike most Germanic headphones, and more similar to Japanese headphones, its sound is definitely tuned by the ear. And what I mean by this is that rather than being tuned to dig from the lowest to highest frequency, HD650's sound is slightly n-shaped with an intimate midrange, a polite treble and warm bass. 
 
Treble-wise, the HD650 has very good extension with some elevation in the very top end. I don't consider it to have rolled off treble like newer Sony headphones have, though it's not a highly dynamic and front stage treble like on some Beyerdynamic headphones. It's present, yet subtle. The lack of a ton of lower to mid treble DOES make the HD650 a little less than perfect for orchestral music due to less  airiness, but it still has enough texture for acoustic music. That said, the HD650 will still show sibilances and some grain with poorly recorded music. Extremely sibilant tracks, especially on lower powered systems that may strain somewhat, will still have some harshness, even on the HD650, and the slight graininess to the lower treble can add to this. But it's infrequent enough that I don't consider this to be a deal breaker in any way.
 
Mids are the true forté for the HD650. The mids are fairly intimate and forward from the lower midrange to the upper midrange. After listening to the HD650s, many other headphones will often sound "hollow" or "scooped", with some withdrawal or midrange recession in comparison. Female and male singers alike sound equally strong, and instruments have a natural timbre to them. People who love a front and center midrange without the added brightness of the treble will love the HD650. There is little to fault. As I mentioned in the amplification section, though, watch out for amplifiers that are overly forward sounding, as they can make the mid-forward HD650 harsh, brash or blarey. Headphone amplifiers and tubes with a neutral to somewhat soft midrange work best with the HD650. 
 
Bass is an interesting point for the HD650s=, and along with treble, is responsible for the HD650's highly enjoyable midrange. Upper to mid bass notes are forward, textured and extremely present on the HD650. It does not have that overly "groovy" sounding bass like the AKG K240 MKII/Studio due to a highly boosted upper bass, but its bass is more upper and mid-focused than say, a Beyerdynamic DT990. This creates the more filled-in sound of the HD650's mid range. Wind instruments and bass guitars are excellent on the HD650. The mid bass has some bloom to it, and while not the tightest, lends well to drums, and synthesized mid bass with house, trance and dance music. The sub bass, however, is the HD650's weakest point in its low frequencies, as it rolls off after the lower mids. This makes it not the best headphone for genres that need a more filled in or neutral low end such as hip-hop and drum and bass, or genres with powerful drumming such as Japanese Taiko drums. Due to the lack of low end bass, but extra upper to mid bass, the HD650 has a somewhat soft or liquid sound to it. The extra upper bass gives the HD650's bass timbre a more chesty or "wooden" sound that lends well to African, Arabian and South Asian genres of music. 
 
Soundstage, while being good with depth, lacks the layering and precise imaging of other headphones. This gives the HD650 that characteristic "3-blob" dimension to its imaging. You hear music from outwards, up and down, but instrument placing and layering is not as distinct. I would say that for symphonic and orchestral music this is probably the biggest weakness of the HD650.
 
There are a number of alternatives to the HD650 one might wish to consider instead. The obvious one is its older but still produced sibling, the HD600. The two are basically the same headphone design, with the finish of the plastic being different color schemes, the HD600 being a little less expensive, different headband padding, and the HD600 cable being thinner and terminating to a 3.5 mm connector. Both have a similar, mid-prominent lushness to them, but the HD600 gives up some bass energy and trades it for a bit more treble, which gives it a more acoustic and orchestral-friendly sound somewhat closer to neutral. The two from what I heard are similar enough that owning both isn't worthwhile unless collecting is an endeavor. 
 
The AKG K702, Q701, and K701 are often compared to the HD650, but they are lean and bright enough that they should be compared more to the HD600 than to the HD650. I owned a Q701, and it is a completely different sounding headphone, with deeper but harder ear pads, lesser grip but a bumpy headband, a zazzy upper midrange, bright lower to mid treble, tight and neutral though dry bass and a soundstage with outstanding airiness, layering, texture, dimension and imaging that made the headphone excellent for jazz, orchestral and symphony, and acoustic music. Though the strong upper midrange made the Q701 a bit too aggressive at anything above moderate listening volumes for trumpets and saxophones, and women singers who sing at high and loud octaves (e.g. Adele, Rebecca Ferguson).
 
A fairer comparison would be the newer K712 Pro, or the K702 65th Anniversary Edition, as their sound is more comparable to the HD650. I have compared the HD650 to my brand new AKG K7XX Massdrop Edition that is tuned to sound similar to both the K702 Annie and the K712. Compared to the HD650, the K7XX is more comfortable and less tight fitting. The K7XX has more treble and more sub bass, while being a little more withdrawn in the mids than the HD650. The K7XX like most AKGs is highly source-dependent. It will sound like garbage on garbage recordings, and it will sound sibilant on poorly matched systems, unlike the more source-forgiving HD650. I will be writing a more detailed comparison review of the K7XX and the HD650, so more comparisons will be found there. 
 
The closest Beyerdynamic for comparison is the DT990, as the DT880 is flatter and more comparable to the HD600. The DT990 Pro is less expensive than the HD650, and has a prominent u-shape to its sound, with very dynamic and bright treble, deeper and more rumbling sub bass and mid bass, a wider and more open soundstage, and a more scooped midrange. The HD650 is definitely the softer and more laid back of the two, and the DT990 the funner, more exciting sound. Both make excellent complements to one another for different listening moods. The DT990 Premium models are a little more neutral, with the DT990 Premium 600 ohm having the smoothest treble of the 990 models, and being the closest competitor to the HD650 due to its refinement. 
 
In the planar range, Hifiman's HE400i is priced at the same 500 dollar mark as the HD650. From what I have read, the HE400i has a strong clamping force, is somewhat heavier, has deeper extending and tighter bass, and the treble is more energetic. 
 
Another option to consider is the recently released Philips Fidelio X2, which according to reviews from owners, has a tighter and more present low end than the HD650, a more neutral treble, and a wider soundstage. 
 
While the HD650 at times can be soft sounding and isn't the most comfortable for long listening sessions, it nonetheless will remain a staple headphone in my fleet. I'm interested in seeing what upgrades to DACs and better tubes will do to improve refinement. 

I will get my bias out of the way first: I really enjoy the sound of many Sennheisers, and in my opinion the Momentum Full Size is the best sounding portable I have tried, and the best all-round sounding consumer-targeted portable headphone on the market. 
 
Appearance-wise the Momentum is, as I mentioned, an exquisite feeling headphone. It reminds me of that modernist British industrial design that is the Bowers and Wilkins P5 and P7, but more classic or vintage looking (cough cough hipster) and with aluminum instead of stainless steel. The headphone is basically an aluminum headband with two ear cups fastened on. The headband padding and earpads are made from lamb leather and the ear cup housings are made from glass-filled plastic. The ear cups are tension-adjusted by sliding them up and down on the headband; there is no ratcheting or click adjustment. My Momentums are the black model with red cabling, a black with red stitched carrying case, red stitching on the headband, and red cloth covering the driver baffle plates inside the ear cups. The ear cups are a matte finish, which does concern me about picking up scratches. The cable connecting the left and right channels is the same material as the input cable, and may worry some people as the wires are exposed and may snag on something and tear. As for appearances out on the street, the Momentum doesn't immediately look like a theft magnet or something that shouts "I'm super expensive". It's a bit like the Audi A4 of portable headphones. At first sight it might look like a much cheaper-priced retro style headphone like the Panasonic RP-HTX7, and to me adds to its value of being able to be used in public. Overall I wouldn't say the Momentum Full Size isn't as sturdy as the V-Moda Crossfade M100 or the XS, and the padding due to the delicate leather material is less durable than the Alcanatara on the Momentum On Ear. But the earpads are replaceable.
 
The cable is a mixed bag for me. Sure it's a good looker, has a metal fob with 3 button iOS controls, a good microphone, and an aluminum jack with a 90 degrees of movement variable adjusting plug. But the rubber coating the cable is thin and develops kinks rather easily. I am also concerned about the lack of strain reliefs on the terminations to the ear cup, the input connector, and the remote fob. But after a couple accidental tugs rest assured there was no breaking and the connector simply detached from my phone. As for spares, the Momentum does come with a plain spare straight cable, but with no remote and no variable angle jack. And because the cables terminate to a 2.5mm connector on the ear cup with a bayonet lock, getting a replacement should you destroy the iOS cable requires you to buy a genuine Sennheiser cable at a cost of 70 dollars, or 50 dollars for the Momentum On Ear cable that has no metal fob body and a 90 degree fixed angle jack. Ouch.
On the bright side there are plenty of manufactures (usually from China) on Ebay offering aftermarket cables made specifically to be compatible with the Momentum's 2.5mm connector, with iOS controls for a much lower price than a genuine one. And if you want to go crazy, I believe there are some cables purchasable for the Momentum made from pure silver or copper and silver. For an arm and a leg of course. The case is nylon coated, has a sturdy zipper, is padded inside with a hook and loop pocket to store your cable, but it's big in size and requires you to push the ear cups all the way to their top positions in order for them to fit into the slots. 
 
Now onto comfort. The headband padding is rather hard and splits into two rails. This can cause some digging into the scalp if the headphones are not adjusted properly. I usually sit them flat on the top of my head and am usually fine. The headphone is also rather light so this helps. The Momentum was advertised initially as an around-ear headphone, but for most people it isn't. The ear cups are simply not wide and tall enough for most peoples' ears. I find that the hard cartilaginous areas of my ear tuck inside the cups and rest against the cloth inner walls, but the bottom of the pads rest on top of my earlobes. I have big ears, so if I don't adjust the cups just right, I find the hard areas of my ears pressing against the plastic baffle plates, which can hurt over time. Since they still fit around the larger areas of my ears, they are more stable and won't just slip off, but since they are very cozy and squeeze the edges of my ears, I find that I have to take the Momentums off every hour or so to let my ears breathe, and then I can put them back on and resume listening. Prolonged wear without a break causes my ears to become hot, sore and pinched. In my opinion, this is the biggest drawback that can spoil the overall experience of the Momentums and their initially lofty 350 to 400 US dollar price tag. They sound so good that you will want to listen to them for hours on end, but your ears will likely object to this prolonged listening session. 
 
And finally the sound.
 
I purchased the Momentum Full Size after briefly owning the Momentum On Ear and returning it due to not liking its signature. I found the On Ear to not only make my ears red hot and sore from as little as a half hour of wearing time, the treble was too splashy, the mid bass too overbearing and the vocals too withdrawn and the headphone rather unsatisfactory for genres other than pop, hip-hop, trance, dance and harder hitting house music. The Full Size Momentum is a much different sounding headphone. The Momentum to my ears has a linear enough response that from bottom end to the lower treble, there is plenty of information portrayed. If one looks at the frequency chart, the Momentum has an almost flat curve from the sub bass to the lower treble, where it begins to roll off. Now some people will argue that the Momentum is slow, muffled, and bass heavy. I argue that the people who say that are likely treble heads. For you guys I recommend the Bowers and Wilkins P7. 
 
There isn't an up front treble that gives the Momentum an immediately forward and sparkly sound. So it may sound shelved in the vocal range or slightly echoey. But once your ears adjust to the sound signature, you will find that they have a sound that goes well with almost every genre. The treble still has plenty of detail, but is never harsh. To me it's more subdued than it is softer. 
 
The mids have a liquid sort of sound to them that while they may seem polite, have plenty of energy in the vocals. The upper mids have a little bit of a glare or splash to them that may become blarey at higher volumes with trumpets, saxophones, and female singers, but for most of the music I listen to (soul, smooth jazz, Spanish guitar work, Japanese electronica, baroque, pop rock, house, hip-hop, Arabic pop and drum and bass), this isn't much of an issue.
 
The bass is really where the Momentums shine. The bass from the lower bass to the upper bass has excellent presence, impact, detail and is never overblown. The mid bass to my ears has a bit of that Sennheiser wooden-like bloominess (like the HD650) that makes it a tad loose, but it never becomes one-note or droning like the Momentum On Ear became. The upper bass blends into the lower mids excellently without adding an overly chesty sound like the Audio-Technica ATH-M50 did to my ears, or adding too much forwardness to already forward mids, making the headphone sound honky (like the V-Moda XS). The sub bass is done exceptionally well. It has plenty of tightness, rumbles when it needs to (for drums and hip-hop) quick decay (the notes don't hang around and sound muddy), and isn't overemphasized. So it doesn't sound boomy, slow, loose or overly rumbly. The bass to my ears on the Momentum is exceptionally coherent. It doesn't have an overboosted upper bass with a woeful bottom end, making it sound honky or overly warm at times (like the AKG K240 Studio/MKII). It doesn't have a droning, over boosted mid bass like the Momentum On Ear. And it doesn't have a conspicuously powerful sub bass with a thin upper mid bass and sucked out upper bass, making it sound overly bottom heavy with an unnatural and lean transition to the midrange (like the Beyerdynamic DT990 Pro 250 on a solid state amp, the Sennheiser HD380 Pro, and Beyerdynamic Custom One Pro). 
 
Sound character-wise, the Momentum reminds me of a closed back, slightly less hi-fi HD650 with a more boosted bottom end, a slightly less forward midrange and more shelved off-sounding vocals. If black on the Momentum isn't for you, there are two other color options. There is brown Momentum with oliveish/coffee brown colored padding and satin-finished cups, and the ivory Momentum with tan ear cups, medium brown headband, and black earpads and black padding inside the headband. I have read that with cleaning the leather on the brown Momentum can turn black or darker after a while. So if this is a concern, the black Momentum or ivory version with their black inside (i.e. the parts that touch your scalp and ears) padding may be a better choice. In retrospect, I wish I chose the ivory Momentum over the black model due to looks with my phone being white, but the black model is still a good looker, and probably blends in better with my blackish hair. 
 
Quick comparison with the Sony MDR-1R
 
The Momentum has a more impactful, fairly forward, and harder hitting sound than the Sony MDR-1R, which is a headphone with a more dreamy, sweeter, diffuse midrange, wider soundstage imaging, a softer treble, and a bass that dives off after the upper mid bass. The MDR-1R has a distinctly Japanese-style sound tuning (politer, laid back and tuned more by the ear), whereas the Momentum has more of an ear and frequency measurement-tuned sound. It's a more German sound but with warmth. The MDR-1R is softer and much more of a polite, relax-with-music-in-the-background sort of sound; whereas the Momentum is a more forward, demands-to-be-up-front sound, with a subdued treble. One suits a listening mood more than the other. While the 1R is more relaxing to listen to and more comfortable to wear, the Momentum grabs my attention more and is a funner listening experience. 

I have owned several other AKGs, including the K240s, the K702 65th Anniversaries, the and Q701 Quincy Jones Signatures (basically the same thing as an updated K701/702). The K612s sound-wise lie somewhere between the K240s and the K7-series, while having a unique sound signature of their own. 
 
Build: Made in Austria, and very close to the K7-series, but not exactly. They feel high quality, but not quite as exquisite. The plastic on the ear cups is of a slightly lesser quality compared to the K7s, but is still good quality nonetheless. The headband is a stitched genuine leather band just like the K7s. The cable is 10 feet and hard wired, so not detachable via a mini XLR jack like on the K240s and K702/Q701/K712, but is good quality. It terminates to a 3.5 mm jack with an included 6.3 mm screw on adapter. 
 
Comfort: Keep in mind that these are not fully broken in. The K612 is right up there with the the K7s, but WITHOUT the angled ear pads and headband bumps of the K701/K702/Q701, and a harder padding than the memory foam on the K702 Annies and K712. The pads are fairly hard against the head due to the firm padding and the clamping, so will be a bit less comfortable at first. However, when they start to conform to the shape of your head, they become much more comfortable. The pads are deep enough for most people's ears, however I have a point on my left ear, and recently I found that point touches the driver covering, causing irritation. To remedy this, I took off the left pad and removed the foam ring insert. This supposedly changes the sound ever so slightly but I don't really notice. Since removing that foam insert I find the left ear pad much better. As far as I know, the K612 pads are interchangeable with the K7-series ear pads. 
 
Sound impressions:
 
Lows: The K612s lie somewhere between the K702s and the K240s, with having more bass than the K7s, but less than the K240s. Both the K240s and K702s have a sub bass roll off, with the K702s having a lean bass overall, and the K240s with a strong upper bass and mid bass. The K612 have a thickish sound to them, but with the bass being surprisingly linear across the board and without any particular hyping of the sub bass, mid bass or upper bass. As a result I find the K612 has a very clean and accurate sound to the bass. Now bassheads might not like this, because for tracks that are mastered to require a boosted bass, the K612s will sound untextured and the bass will end up sounding artificial. However, if the track is mastered to not require a colored bassline, or is natural bass from recorded instruments, the K612 does exceptionally well. Like most other AKGs it likes recorded bass a lot, but unlike the K7s, it still does well with synthetic bass if it is mastered right. The K612s are good headphones for quicker, more transient bass like with progressive trance and liquid funk. The bass right out of the box will not sound right, and will have a dip in the mid bass, so burn in is a must to bring out the bass potential. The timbre of the bass has a sort of acoustic, instrumental or almost "wooden drum" sound to it, which gives it superb transparency for recorded music. if you listen to powerful piano playing like Alicia Keys, the K612 does an excellent portraying a sense of sound of low notes she plays. If you listen to Arabic pop or Bollywood, the K612 does a superb job representing tambourines and tables. Coming from a Sennheiser HD598 or in some cases an HD600, you will find that the K612 doesn't have that speaker-like, slightly synthetic sound to it like they have. Its bass has a very "instrumental" sound to it.
 
Mids: In one word: linear. They are linear across the board, without being glarey in the upper mid range like the Q701s and K702s are. Because of this, they are very easy to listen to. There is a smooth mid range without being dipped to sound tolerable, like on Beyerdynamic DT990s. I have absolutely no complaints with the K612 mids. They are pretty much perfect for me in this regard. They have that characteristic AKG house sound for musicality, so you aren't missing anything there. The mids really don't make any compromises to be easy to listen to. They aren't rolled off, they aren't dipped, and they aren't veiled like with some Sennheisers. 
 
Treble: These headphones have no particular spike in the treble. It's quite linear across the board, with roll off happening towards the 8-10,000 Hz range. You have to play REALLY badly mastered music for these headphones to sound sibilant. The treble is there, but it isn't forward, harsh or glarey. The K612s are't as dark as the K702 Annies, but are definitely are more forgiving than the K240s, which I find are rolled off in the lower treble but abruptly have a HUGE spike at the sibilance range that makes them piercingly painful with badly mastered music lest I EQ the treble down.
 
Soundstage: The K612 has improvements to the bass, but there will be inevitable trade offs made. One of these to a minor aspect is the soundstage. The K612s just cannot compete with the soundstage on the K701, K702 and Q701. They do however have a more open soundstage than the K240s. Despite not having as wide as soundstage as the leaner K7s, I do find the K612 soundstage more natural due to not having the tendency to pan extremely left and right with mono recordings, causing the center stage to go dead like the K701/K702/Q701s do. 
 
Amping: I run the K612s off my Maverick Audio A1 hybrid tube and solid state amplifier and Schiit Audio Modi DAC. I am more than happy with the system, with the K612s taking a liking to the Modi. The K612s also like the FiiO E07K DAC and battery powered amplifier. They don't need as much current as the K7s, and due to being 120 ohms, they can be run off an OTL amp like the Schiit Valhalla. The K612s like the K7s are picky with DACs more than amplifiers; if your DAC is distorting from not being able to handle the equalizer on your computer, the headphones will make this horrendously obvious. So make sure your DAC is up to snuff. The internal DAC on Macs just won't cut it. 

There's not a whole lot I can say about these. I think they are an excellent compact headphone to have in a bag on the go, they are affordable, sound good with everything, and are a definite step up from the crummy earphones that come with most cell phones and iPods.

I bought the DT990s for use with bass music such as hip-hop, drum and bass and electronic dance music to compliment my AKG K702 65th Anniversies, which I have since sold. 
 
Build and comfort: the build on the DT990s is excellent like most Beyers, and is made in Heilbronn, Germany. It is made from high impact plastic for the cups and spring steel for the headband and bales (yolks), with replaceable velour ear pads and a replaceable vinyl headband pad. The headphones are very grippy and tight, so that may be an issue for you guys who are sensitive to caliper pressure. It is not an issue after about 5 minutes of wearing. The pads have plenty of space for your ears. I have a badly (seemly) disproportionate left ear, so the back of the left pad slightly touches the back of my left ear, so sometimes it is a little irritating if I pay attention to it. Otherwise I don't have a problem. The yolks are metal and the headband is made from spring steel, so don't feel afraid to bend the yolks and headband out slightly to loosen the grip. This will keep the ear pads from collapsing and causing the drivers to touch the ears. Headband comfort is not an issue whatsoever. Keep in mind that these have a non-field serviceable hard wired 3 meter coiled cable terminated to a 3.5 mm plug with a screw-on 6.3 mm adapter, which is a must to use since these need a desktop amplifier.
 
Treble: Bright? Yes. Grainy or overly metallic? No. The treble on the 990 Pros is strong and very present, yes. I would call it more revealing than colored overly bright. But at the same time it isn't what I would call overly harsh. It is only harsh when a song is sibilant or badly mastered, and that is noticeable in the 8-10,000 Hz range. Thankfully, the 990s are very responsive to EQing, so all you have to do is turn the treble on the 8 kHz range down a decibel or two below flat, and that will take the bite off the treble nicely. But what I like most about the treble is that it isn't crunchy, metallic or grainy. Grain is the number one cause of ear pain for me, and it is why I hated the way the Audio-Technica ATH-M50 and the Beyerdynamic DT880s sounded in the treble region. I would say that the DT990 Pros have even less grain than the so-called laid back Sony MDR-MA900s.
 
Mids:  The midrange is much smoother and has a warmer, dynamic sound without being harsh. These are not the most mid centric headphone for the price, though (the AKG K612 Pros for 199 US dollars are better for mid centric music), as there is a u-shape to the sound signature. Mids are still natural sounding though. 
 
Bass: One word: Authoritative. The bass on the 990s hits hard, but it is not overly boomy so it doesn't give me an earache like on the DT770 Pro 80s. This is a great headphone for drum and bass, electronic dance music and hip-hop. The only downside I have is that the upper bass is a little thin, so bass signature is more of a rumbly, mid to sub-bass-centric sound. Unlike the AKG K240s or Sennheiser HD25s, which have more upper and mid bass than sub bass, and as a result, have a more punchy, visceral, warmer bass which is a little more suited for rock, some dance and jazz.
 
Source and burn in: When I first plugged them into my Maverick Audio A1 amplifier, I immediately had tinnitus from the ringing, overly splashy treble and boomy bass. After giving them about 20 hours of burn in, they settled down nicely and that harsh bite to the treble and overwhelming bass were taken off. These headphones still remain bright whether they are on a solid state or tube amplifier, but they are MUCH more dynamic on a tube amp. On a solid state, they will sound harsh and mechanical. Tube amps I recommend are the Maverick Audio Tubemagic A1, Little Dot amps, and the Woo Audio WA6 and WA7 are both supposed to be excellent matches for the 990 Pro. 
 
I think that for the price, these headphones are a steal considering what you get for your money. Just keep in mind that you need to get a desktop amplifier for these to sound their best, preferably tubes. You can get a Maverick Audio A1 or Little Dot MKII for around 200 dollars. So you can have a serious listening rig for under 400 dollars. Highly recommended.

I purchased the MA900s to go along with my AKG K702 65 Anniversaries, as I wanted a headphone which didn't require amping and would be a little more musical with synths (AKGs tend to be too honest and 2D and untextured sounding with electronic and synthesized bass, and prefer instruments more). And so far, my impressions are that these are a great open-back, all-rounders for beginning audiophiles who want a headphone that goes well with almost every genre (save for bottom heavy stuff like dubstep and more mainstream rap) but do not have the amps and other equipment necessary for other open backs such as Beyers, Senns and AKGs to perform at optimum levels.
 
Much of my electronic music is disco, diva and deep house; and liquid funk (downtempo drum and bass), which I prefer to sound more airy, quick and upper to mid bass-oriented with emphasized vocals. The MA900s handle both of those genres admirably well and remain quick. They have a slightly rolled off, although still airy treble, which is what I prefer for downtempo music. The MA900s also handle downtempo trip hop and neo soul well with their smooth vocals and dark sound. The MA900s are overall a mid bass and mids-heavy headphone with roll-off on both the high and low end. Sonically, they remind me of a cross between a slightly rolled off AKG Quincy Jones Q701 (with its musical, neutral but lean misds) and the laid back sound Sennheiser HD500-series but without the thick lower mid bass and echoey, somewhat reverberated vocals. Although on paper it would be similar sounding to the AKG K702 Annies and K712 with its slightly elevated mid bass and rolled off highs, the MA900 is less analytical and has a more airy sound from my listening experience with less thickness.
 
Ear cup comfort is a little so-so FOR ME, and this is due to the fact that I have overly sensitive ears. If I shift the earcups all the way forward, my ears do not touch the driver cover padding, however the edge of the pads dig into the cartilage behind my ears, causing them to become sore. I find that shifting the headphones slightly back to where the driver pads lightly touch my ears is the most optimum position for comfort. I usually hate having things touching my ears and creating hot spots, but it over time it ceases to become an issue, and my ears quickly settle in. Will most people experience initial comfort iffiness like I will? No, but for those who have sensitive ears, you might want to keep this in mind. The MA900s do not have the roominess of Sennheiser ear cups, but they don't have those echoey vocals and head clamp, either. 
 
The MA900s are fairly light and lack that bulky feel that AKGs and Beyerdynamics have. Which means they don't feel overly cumbersome and are ideal for longterm music listening sessions, but this does mean their build quality is unfortunately rather on the floppy side. They don't have that chunky, substantial feel like Sennheiser HD518s or HD598s have. However, the MA900s have a large amount of magnesium in their build, comprising the driver back grill, the yolk and the yolk arms attached to the ear cups. The MA900 does look and feel premium, it just does not feel rugged or chunky.
 
Another small complaint I have is the cable, which is hard wired, skinny, long, terminates to a standard 3.5 mm jack which oddly has a plastic barrel surround. On a positive note, the jack is fairly slim and will easily fit in an iPhone case. And that ties into my final point. The MA900 has a nominal impedance of 12 ohms, and although they benefit from amping, you don't need one to get them to sound good (unlike AKGs). You could run them off a potato if you wanted to. The phone case-friendly 3.5 mm jack and included snap-on stereo plug that seems like an afterthought hint to me that the MA900s are not mainly targeted towards the audiophile who has tons of high end gear and likes to swap for higher end cables, but to the average consumer who wants a no-fuss, elegant, relaxed, dynamic-sounding headphone.
 
If you have a good amp and want a drier, more analytical sound, I would suggest instead checking out the new AKG K612 or Q701 instead. But if you are a beginner with open backs and do not have an amp to work with, I cannot recommend the MA900s highly enough. Just make sure to treat them well and not be rough with them. They retail for 300 US dollars, but you can get them for less than 200 on Amazon. A great headphone for around 200 dollars.  
 
Update: The ear pads, which were initially too pokey and hard have since broken in over time, and have become much more comfortable. I expect this comfort to get even better over time. 

I purchased the DT880 Pros as my first open/semi open headphones, after returning the DT770 Pro 80s due to earaches from the excessive bass. I am a bit of an analytical headphone person with certain genres I listen to. When I first tried the DT880s, I was impressed, but after listening for a while, the shortcomings became more apparent. 
 
For sub bass, these are probably the most sub-bassy analytical heaphones I have owned. There are more bassy analytical cans, however. The problem I had with the DT880s were the earpads. It's not that they aren't soft, because they are. They are just not large enough, so the drivers ended up touching my ears. Anything touching my ears is a HUGE pet peeve of mine, as it makes my ears itchy and red from irritation. But the biggest problem I found about the DT880s was the treble. It has some of the worst treble of any headphone I have listened to. It's sharp, unrefined, and metallic. It has the finesse of someone banging on a dumpster with a hammer, giving me an earache, and strangely, a taste of metal in my mouth. I like treble, but not like this. The bottom and top sound heaviness to the DT880 gives it a rather bland and uninvolving mid and vocal section with not enough mid bass to my ears.
 
Compared to the AKG Quincy Jones Q701, the DT880 has a more comfortable headband, is a little bit more durable feeling, has a faster decay of notes, and more sub bass. But other than that, it's an inferior headphone in every other way. The soundstage is MUCH wider on the Q701s, notes hang in the air more, and the treble, while bright, is more like a plateau, and not a mountain range of spikes. There is also more 10 kHz roll off than the DT880s, which I prefer. The mid range and the mid bass on the Q701s is MUCH better than the DT880. And there actually IS a mid range, as well as a more rhythmic sound overall. The DT880s will be better for electronic music than the Q701s when amplified properly, but as an analytical headphone with still some musicality goes, the Q701 is hands down better. 

I chose the HD380 Pros to replace my Audio-Technica M50s, and have not looked back ever since (except to compare the M50s to the HD380s with songs). Sound-wise the Senns are superior to the M50s in every way. More realistic bass, non-flabby but without losing impact, MUCH better mids, more refined treble, and the ear cups on the 380s are tremendously better than those on the M50s. Whereas the M50s sound best with electronic music such as house, drum n' bass and trance, the HD380 Pros are not only good for those genres, but are great for R&B, rock, jazz, soul, and pretty much every genre under the sun other than classical music (a little too bottom heavy). The HD380s have a more spacious soundstage imaging than the M50s, due to the cleaner, less wooly bass. Since the M50s are going up in price again, and the H380 Pros are going down from their 199 dollar MSRP, I highly recommend the HD380s over the M50s. They will treat your ears better with the roomier cups, and will never fatigue your ears from treble assaults and harsh female contralto vocals, unlike the M50s. Keep in mind that the HD380 Pros do sound their best with an amp, but will have no problem running off an iPhone, Macbook, iPad, Galaxy S4, etc. Also, the HD380 Pros have a user-replaceable cable. Highly recommended. 

I purchased the HD518s for a good price lightly used, and have been very satisfied with them. They are darker Sennheisers, and have the signature Senn smooth sound. I have never owned Senns before, so these were my first pair. I am fairly used to how AKGs sound, so when I first listened to the HD518s, they initially wowed me with how smooth their mids and highs were, and how strong the bass was. There definitely is a "wow" factor when you first listen to them, especially if you listen to brighter, leaner sounding headphones. They are all plastic, but feel well made. They have that Sennheiser vice grip on the head, but you get accustomed to the grip, they do not present a comfort problem. The earpads are fairly stiff, but do not munch my ears whatsoever, and the cups absolutely deep enough that my ears have never touched the drivers and never will. The headband has some cloth padding, and hasn't given me any problems. They have a detachable 10 foot cable, so that is a plus. The standard plug is a 1/4 inch stereo plug, but they come with a 1/8 inch adapter. The problem is that with the adapter on, the jack becomes absurdly long, and presents a hazard of sheering off when connected to a laptop, iPod, iPhone, ETC which use 1/8 inch headphone jacks, and require use with the adaptor.


 


Sound wise, the HD518s are dark and smooth, so they are easy to listen to brighter music with for longer periods of time. Their bass impact and open back design also makes them excellent for watching movies with, as well as playing video games. Soundstage for music isn't very wide, however. The HD518s have a polished sound, but this may be problematic to some. The highs don't have the sparkle to them that I am used to with AKGs, for example. They have stronger bass, but the problem is that the bass is a little obese and loose, and tends to have its main impact in the lower mid-bass region. That makes the HD518s sound as if they have somewhat indecisive, slightly confused bass. The mids are a little too smooth and veiled, and tend to lack a lot of musicality. Vocals are fairly veiled, and tend to be a bit too thick and unemotional to my ears. They do every genre competently, but tend to excel at darker, downtempo music with a strong bass impact. RnB, Quiet Storm, Chillout, Liquid Funk (downtempo Drum n' Bass), and smooth jazz sound great on the HD518s. Genres that require a quicker, more transparent and leaner sound do not sound their best on the HD518s. 


 


Don't get me wrong. The HD518s are great headphones. They are just a little bit too veiled in the vocals and obese in the bass to be my everyday headphones for music listening. A bit too vanilla sounding for my tastes, but I can completely understand why people like the Sennheiser sound, and why Sennheiser has such a loyal customer base. I strongly recommend anyone looking for good starter open backs for a variety of genres, or want good headphones for video/computer games as well as movies, and do not have a higher end equipment to drive headphones with, check out the HD518s.  

UPDATE: I made a few updates after comparing the Annies to other headphones in the my collection, and running them on my Maverick Audio A1 hybrid amp.
 
The K702 "Annies" are basically the sonic precursor to the K712 Pros, which just rolled off the assembly line. Think of them as a Quincy Jones Q701 but with squishier ear pads, no headband bumps, softer, less sibilant highs, a little more mid bass, more intimate vocals, and a thicker sound. Instruments don't quite float in the air like they do with the Q701, but to me, the less bright highs and non-aggressive upper mids make them easier to listen to for longer periods of time, and surprisingly make them a bit easier to pick out nuances due to a less distracting bright treble.
 
The bass is definitely there, though not as much as the K240 Studios/MKIIs, and does't really have much physical slam. The Annies still have that fast (compared to some dark Sennheisers) sound, natural mids and vocals which I love about AKGs. They are a little thicker sounding than the Q701s. Take note that they aren't very strong in the sub bass, or with synthesized bass. They don't like synthesized bass, unlike the K240s, which slam equally hard with synthed bass as instrumental bass. But they are great at reproducing well defined bass from drums, upright basses and bass guitars so they do a good job with more instrumental hip-hop like The Roots and Q-Tip. Overall though, the Annies don't have much bass slam at all.
 
For the price, they are great headphones that take a good middle ground between dark, laid back Sennheisers, and analytical, lean, but musical AKGs like the Q701 and K702. After owning them for a number of months and using them on different amps, however, I am come to the conclusion that the K702 Annies are a dark, analytical, but NOT a warm headphone. So don't expect any foot tapping action with them. They are meant for relaxed, dark, analytical (maybe this word has become trite by now) long term, late night listening, which makes up maybe about 30 percent of my listening. When I say the K702 Annies are still a K7-series, I mean that they are still somewhat dry, not very warm, lean, picky with amps and systems, but in this case, thicker and darker headphones rather than slightly bright, extra lean, quick and airy K7's (Q701s, K701, normal K702s). I have pretty much found out I am more of a warmth and energetic headphone sort of person (Beyerdynamic DT990 and AKG K240), so these are a bit dry and rolled up for my tastes. Still, for the right person, the K702 Annies are magical.