There are very few headphones which have survived three decades and still remain as the main workhorse for many sound professionals around the world. The Sony MDR-7506 started out as the MDR-V6 exactly 30 years ago. Understandably back then the headphone landscape was much different and these were an instant favourite amongst many sound engineers. Praised for not only great sonic performance but also well thought out ergonomics the MDR-V6 became a classic and Sony decided to do a slightly higher priced spin-off and call it the MDR-7506. The younger brother of the V6 has slightly better build quality and initially used the same driver with samarium-cobalt magnet which was in the late 90-ies replaced with a stronger neodymium magnet. Unfortunately the magnet swap happened without changing the serial number, hence it’s hard to know what version exactly one has.
 
Traditionally the MDR-7506 has been a favourite amongst live sound engineers and looks like this means that these Sony headphones have found their way into studio control rooms as well. Like the equally venerable Yamaha NS10 monitor it has become something like a standard amongst many practicioners, but does its live sound pedigree automatically make it good for mixing and mastering - read on to find out!

 
 
 

 
 
The MDR-7506 is known for its bright-ish sound signature, which is usually thought to be “the” studio sound. Our measurements show that the MDR-7506 could actually be well suitable for live sound aplications, but for studio use most will find it to be rather bothersome.
 

 
 
First off - it’s safe to say that this Sony headphone isn’t known for its bass. The low end starts to roll off at 50Hz which doesn’t mean that you’ll be missing much of the music, however for serious studio use it is insufficient. High THD doesn’t help here - for most of the samples we measured it peaks at significant 15% at 100Hz. Your 808 kick tail will have possibly nice drive to it, but do not be fooled by it - its the headphones that are giving those nice overtones not the sample! We would recommend avoiding mixing bass with these headphones at all costs.
 
100Hz - 2KHz shows good linearity with minimum channel differences. This is the region where usually most of the musical information resides, so despite its other shortcomings the MDR-7506 does much right. Usually if your mids aren’t on point, then who cares about the rest? Pretty sure that it’s the clean mids which are responsible for MDR-7506’s fame.
 
After 2Khz is where the real trouble starts. Severe peaking starts in this region right up to 10KHz where a gradual peak up to +10dB makes these sound very harsh and at times sibilant. We can see this might be useful in live applications, like when you need to quickly check for some hissing or noise in some channels. Also you will get extra lows and mids from the PA (and room) whilst wearing these, so for live applications this peaking could actually make sense, but not for making critical mixing decisions. In studio environment the high frequencies will be very disorienting. Most music simply sounds harsh on these cans. The hihats and cymbals will just be too much to bear. Also the de-essing can not be properly done, just like on the M50x. Your mixes most probably will sound quite dull on other systems. All in all these would be rather good headphones if it wasn’t for the over hyped highs.
 
Interestingly enough the very top octave on the MDR7506 is pretty tame. After 11KHz there is a steep roll-off, which masks many overtones for both instruments and vocals. The perceived effect is a congested sound with very little stereo width.
 
 
 

 
 
The calibration effect on the MDR-7506 is very pronounced. Contrary to the “fun” sounding Audio Technica M50x, post-calibration the MDR-7506 becomes not only more precise, but also euphonic - you can actually start to enjoy listening to some tracks on it!
 
Extra low bass extension will surely be gained by calibration, however the performance ceiling is largely set by poor THD performance in mid-bass frequencies. Tonal richness caused by THD still persists, therefore bass mixing is rather problematic.
 
The linearity increase in mids won’t be easy to detect, however stereo image will be more precise if individual calibration is used. This is where Sony really did it right and Sonarworks plug-in keeps those clean mids intact.
 
Highs is where the most work will be done. Sonarworks plugin removes the “AM radio” tinny sound by completely removing the enormous peak at 2KHz-10KHz, hihat and cymbal tone is completely transformed. Well recorded female vocals and many string overtones will sound much more natural, hence they can finally be mixed with confidence.
 
The 11KHz-20KHz dip is restored to neutral as well. Overtones and spatial cues can be easily heard, making the sound wider. Instruments are more easy to detect in phantom stereo image. This top octave might not be much in the big picture, but we make sure you can hear all of it.

 
 
 

 
 
As a live sound tool the MDR-7506 should be able to withstand daily abuse from being dragged to and fro various gigs. Earcups are made from metal as well as the headband which is wrapped in pleather.
MDR-7506 users should always make sure that their headphones have earpads in good condition, otherwise the headphone starts to lose much of its bass. Luckily the pads are swappable and there are many types to choose from. One must however keep in mind that earpads change the sound signature, hence calibration will only work as intended with pads of the same type.
 
Over the years Sony has decided to stick with a non removable cable, which for a headphone if this type can cause problems. A swappable cable means that you can get back into action if you’ve broken a cable mid-gig.
 
 
 
After analyzing these headphones it’s no surprise why the MDR-7506 is so loved by many sound  engineers. These headphones are clearly made for live sound and on-site recording work as is evident by how rugged are they made. At the same time we were pretty underwhelmed how the MDR7506 performed in studio where a neutral sound signature is needed. Uncalibrated these should not be used as a primary studio monitoring tool.
 
Things do change for the better when Sonarworks calibration is used. The MDR-7506 completely changes its character and becomes a useful tool for mixing many types of music. Bass performance still suffers, could be due to the respectable age of this headphone design, but all in all - the performance gain is tremendous. Calibration is a must for every MDR7506 user, if critical mixing work is planned with these headphones. Sony has done well with this headphones ever important midrange, but we all know that devil is in the details.
 
The Good
 
Very good build quality
Decent midrange performance
Excel at live sound monitoring
 
The Bad
 
Very pronounced peak at highs
Bass performance crippled by high THD
Missing top octave
Non-swappable cable

Intro

This review will mostly focus on M50x’s  qualities from a studio professional point of view – what to expect when using these headphones as a monitoring device for mixing and do they really cut it for mastering work.

Click to expand...

After all, you should make your decisions based on what’s in the material, otherwise you might end up with mixes that translate well on your gear and not much else. Know the limitations of your equipment and you will be able to work around them. This text will attempt to illuminate, what to keep in mind when using the M50x for critical studio work.

The original ATH M50 has been one of the most recommended closed headphones at the $150 price point. Most of its fame comes from the consumer segment. One of its largest communities – this forum – has generated dozens of reviews praising its qualities and excellent price/performance ratio. Currently there is a distinct lack of dedicated pro-audio headphone reviewers, therefore most of M50’s pro-fame has largely spilled over from the consumer audio segment. At the same time both M50 and M50x have an abundance of qualities useful for both music listeners as well as producers.

 

[size=20.0069999694824px]Uncalibrated sonic performance[/size]


Perceived Acoustic Power Frequency Response (PAPFR) graph. Measured at Sonarworks lab with a proprietary compensation curve. Not to be compared directly to AFR measurements from other sources.
 
These headphones perform just like they measure – a fun, clean sound. This is mostly due to M50x’s U-shaped FR and extremely low THD. Looks like ATH has really put in some serious R&D work in M50x’s driver, because THD this low at sub bass frequencies has usually been reserved only to planar headphones. Kudos to ATH for bringing clean bass to the masses!
 

 

Now onto the sonic issues to keep in mind if one wants to use these headphones successfully for music production. All of the M50x headphones we measured exhibited level differences between channels. At 200Hz-600Hz there is a wide dip which drops to around -5dB, whilst not too annoying to consumers, it can cause trouble to LCR mixing advocates. With the M50x, some string instruments like guitars for example will change tonality, depending on how they’re panned. The effect will be subtle, but must be taken into account to prevent chasing ghosts in the mix.

On the top end of the U curve we have a peak at 5.5kHz-10kHz which goes up to +7dB at 10kHz which can cause a number of issues. First of all, too much de-essing will be applied to the vocals, as the peak resides right at the sibilant range. Secondly, your sweeps won’t be as accurate because the FR peak will give you a false sense of rising. In general, this peaking can cause your mixes to be dull – one of the inherent cons of all “exciting” headphones, if used in studio.

The low-end response on these headphones is positively thunderous – there is no sub-bass roll-off until 20Hz and THD stays extremely low. The channel imbalance which starts at about 350Hz is still present, but on lower frequencies it shouldn’t be much of a nuisance. Most of the signal at these frequencies is mono anyway and humans don’t really excel at positioning low frequency sound.

 

[size=20.0069999694824px]Calibrated sonic performance[/size]


After we meticulously measured every dip and peak found in the M50x, our engineer generated a calibration profile. These profiles are available for every Sonarworks Reference 3 plug-in user. They turned these headphones into a serious instrument even fit for mastering. This paragraph will explain what can be gained by applying digital calibration to these already great headphones.

We can bet that when you turn on the Sonarworks Reference 3 plug-in, you’ll wonder who flicked the fun switch off! Resist the urge to take the headphones off and listen to some well- mastered tracks. Your ears will need some time to readjust to the reference sound signature and your first impression will surely be dull for lack of a better word. At the same time, it will allow your mixes to translate well to speakers and just about any headphone out there.

All in all, these headphones are a great candidate for calibration due to the low inherent THD and little change in tonality depending on how they’re placed on one’s ears. Obviously Sonarworks calibration gets rid of the U curve and makes these headphones a perfect candidate for mixing and mastering just about any kind of music. One thing to keep in mind is that the average calibration curve won’t be able to combat the channel imbalance properly, because only individual calibration profiles do stereo calibration.

As always there will be some loss of output when applying calibration. In this case it should be about 8dB, which isn’t too bad due to the fact that these headphones are very sensitive. Most audio interfaces will be able to drive these headphones at ear-splitting levels even with calibration enabled. For some higher gain devices, the loss of sensitivity might turn out to be a blessing in disguise, as it will give more usable volume pot range.

 

[size=20.0069999694824px]Ergonomics[/size]



Just like its predecessor, the M50x has a great fit that doesn’t get in the way of everyday use. Unlike most on-ear headphones, this one doesn’t rely on a strong clamp to achieve a good seal, therefore it is fairly comfy even in longer sessions. One thing to note, however, is that all pleather pads are prone to becoming sweaty in hotter environments.

Construction wise the M50x is decent, but isn’t the tank that is the venerable HD25-II is. Like almost every other headphone out there, most of the outer construction is plastic, however it feels like it’s the kind of plastic that breaks rather than bends on stress. Both earcups are on hinges which allow them to be folded up for a more compact package. At the same time, every moving part does present more points for wear, tear, and ultimately – failure.

This time Audio Technica has given the M50x a swappable cable and generously included three additional cords. The standard package includes a coiled 1.2 – 3m cable, 3m straight cable and 1.2m portable cable. All three of them feature 1/8’’ TRS jacks and the two longer ones have a thread for 1/4’’ jacks. On the headphone end, M50x have a 2.5mm TRS connector which seems to be proprietary due to a locking groove. All in all, kudos to Audio Technica for choosing to go this route because with most headphones, cables seem to be the first to prematurely fail.

Most studios tend to stick with their headphones until they disintegrate due to natural or unnatural causes and very few give attention to earpad wear. We recommend swapping out pads as soon as they start changing their initial geometry. Old pads seal worse and let the drivers sit closer to one’s ears, thus changing the initial FR. Fortunately the pads on the M50x are swappable as well, so the user is able to maintain their headphones at peak performance for a longer time.

In terms of noise sealing, the M50x works well, but again is overshadowed by Sennheiser’s HD25-II and many in-ear monitors. The seal should be good enough for mixing in moderately noisy environments and will guard musician’s ears from excessive SPL’s, but most of the time noise will obstruct the finer details. The seal will also keep the user from disturbing others working in close vicinity, good for mixing on the road.

 

Conclusion

Has ATH hit a homerun again? Could be so – at least for consumers! At the studio professional end, things are a tad more complicated. No doubt, it’s a great headphone with relatively little shortcomings, but the tuning might be too “fun” to be considered reference grade. At the same time M50x’s competition doesn’t fare any better, most of the other closed studio headphones at this price range are starting to show their age. Sennheiser HD25-II scores some hits in the ergonomics department, but its drivers are a bit long in the tooth. Same goes for Sony MDR-7506. Now, Beyerdynamic DT770 is a worthy competitor to M50x sound wise, but the Japanese headphone is able to land some hits with its three detachable cables and superior portability. Everyone at the lab agreed that these headphones calibrate very well and after calibration pose a serious threat to newer higher end closed studio phones like Focal Spirit Pro and maybe even ATH M70x.

In the end, this is a modern headphone meant for modern music. Engineers who work with a lot of bass heavy material will be in for a treat as the M50x offers excellent performance in this regard. They might not mind its other shortcomings, but should keep them in mind. Or they can use calibrated headphones and focus entirely on their work. Sonarworks calibration turns the M50x into one of the best closed headphones at any price.

This will be more of an impressions paper rather than a full fledged review. I haven't got much experience with DACs and a Buffalo3+Ivy is the best I've heard. This is the first multibit DAC I've heard so I cannot tell if it has *that* multibit sound or not. I just know that it sounds different to all of the DACs I've heard before.
 
First of all some facts- this DAC was made in the year 1995 which wasn't the golden age of audio (I regard 80-ies being the Golden age) but one could say it was the time when the CD was at its height. The D/AC-1600 along with its cousins was meant to accompany disc transports and maximize the sound quality that can be extracted from the data they provide. All of these units offer a no frills design that I happen to love that focuses on ruggedness inside and utilitarian looks. On the paper the D/AC-1600 ticks all of the boxes that a vintage DAC seeker may look for- quad K grade PCM63 chips and an equally venerable PMD100 receiver. I'm quite sure that five of these chips alone may fetch a pretty hefty sum at the bay. Other than that the device features four input options- optical TOSLINK, TS optical, AES/EBU XLR and SPDIF RCA. Truth be told I'd rather have a proper 75 Ohm BNC for the coax but as you've seen- very few consumer DACs feature those. Outputs range from digital SPDIF RCA for daisy chaining, analog RCA and XLR for single ended and true balanced outputs. If we look at the datasheet for the device you'll see that the output is fairly hot at 3VRMS and twice that on the XLR's. Most of the amps and pre-amps will be okay with this but, for example, the input stage of an O2 happily goes into clipping. Then again I'm not sure how many of the O2 crowd will choose this DAC, but it's something one must keep in mind. The front is pretty spartan with dedicated input selection buttons and a curious button that switches absolute polarity for those that care. I couldn't hear any difference with flipping polarity and the fact that the switch on my unit is broken seems to indicate that the previous owners also tried plenty to hear it. The front panel also features LEDs for indicating the selected input and the frequency it is being fed in. Let's pop the hood, shall we-
 

 
 
As you can see the unit has a pretty hefty power supply with separate transformers for the digital stage and one for each analog stage. On top of that there is heavy filtering with decent quality electrolytic capacitors that have been shunted with film caps. Actually I'm pretty sure that all of the electrolytic caps on this device are shunted with film caps which shows that costs were not spared for this device. I'll also mention that switching this device for 220V operation is a trivial matter of cutting three jumpers and soldering another two. Now let's focus on the conversion stage-

 
You can see that each channel uses two PCM63K chips, however when listening single ended you will utilize only two of them. Contrary to my initial thoughts the I/V stage is not discrete as it uses op-amps. The radiators that dominate the board are for the MOSFET follower current buffer. My first objection would be directed at this current buffer. First of all the MOSFET's used are not meant for audio use which means that they are not the most linear. Secondly- my unit had bias current a tad off on one channel which meant about 0.5V of DC offset. Re-biasing the MOSFET's without spectrum readings is pretty hard so I just set an arbitrary quiescent current of 40mA and hoped for the best. Luckily there are dedicated test wires for current readings and cutout holes for reaching the bottom PCB so the actual tweaking was a breeze. It seems that the output stage has a DC protection circuit that cuts off at some point but 0.5V didn't trigger it, so hadn't my amp had a DC servo my HD650 would've been fried. Good thing I had a relay based attenuator that gives out a purr when you are having DC at input. Pretty handy. All in all the output stage is pretty pedestrian save for the MOSFET buffer which I find silly. I'm sure one could omit the buffer entirely and get better results. I'll try a simple opamp/BUF634 composite circuit for the output buffer just for the kicks in place of the MOSFET's but honestly- one could do a lot better with a discrete output stage like our member Colin used to make. There's plenty of room for that. A simpler mod would be just to swap out the op-amps with something better as the op-amp tech has improved since the nineties. On the topic of modding Audiotuning.de has some drop-in kits for the digital receiver stage and DAC stages but other than adding the ability of receiving higher resolution signal I very much doubt that it would yield any actual improvement. The PCM1704 is only marginally if any better than a K grade PCM63 and PMD100 is still one of the if not the best digital receiver for 16/48 content. After all the bottleneck of this device, methinks, is the output stage- swap that out and then you could talk about hearing what the PCM63K has to offer. Also the PCM1704 is one of the more expensive DAC chips and I don't really see the point of buying the D/AC-1600 to overhaul it completely for this kind of money. More can be had for less if one goes for a clean slate via DIY.
 
Now for some practical matters. When you buy a [digital] audio device that has almost reached the legal drinking age you must keep in mind that it might have some quirks. First of all- check at what voltage it is wired. Second- keep in mind that the output stage is always on regardless of the power switch position. This has its advantages as many of the devices doesn't have to go through on/off thermal cycles. Then again the MOSFETs in my unit operate at 50 degrees Celsius and the case has almost no ventilation. That can shorten the life of electrolytic capacitors which there are many, however I can't see any signs of them going bad. When you look for the electrolyte leaks keep in mind that most of the caps are glued to the PCB for stability during transport and these brown splats are the aging adhesive. With age many of the zip locks have gone stiff and are really brittle. I recommend swapping out at least the ones on the trafos. When plugged in the top of the unit will get quite warm as it relies on the case to dissipate heat, sure it won't get stove-like but I'd recommend letting it breath. Heck, one day I might try CNC'ing some vents for it. The trade-off would be dust. My unit was completely dust free inside which is pretty remarkable for a device this old.
 
Now for the sound. My audio journey started with the FiiO E10 and then I upgraded to the Pico DAC. The E10 was really great for the price but didn't have the grunt for the HD650 to shine. It was better when I built myself a Dynalo amp and after a while I even bought the Pico DAC as it was highly regarded in the headphone society. I must, however admit that the transition from E10 to Pico didn't yield the improvement I was looking for. I know some folks talk about the Pico sounding better than the Benchmark DAC1 which I can't comment. Pico did sound very good but there was this feeling of remorse that haunted my listening sessions. I guess there is only so much you can do with an USB powered DAC. The final nudge was a listening session when I tried out the Buffalo DAC which blew my mind in many aspects. It had an immense soundstage among other things and showed that my system is DAC limited. At least I was convinced that there's more to be had.
 
For months I had eyed the classified in the FS section where Currawong was trying to sell this Parasound and finally when he threw in the shipping and an Audio-GD Digital Interface I pulled the trigger.
 
As I said earlier- rewiring the D/AC-1600 for EU voltage was a breeze, however setting up the ADG interface wasn't. There is a dedicated thread on HF about the woes that are involved in living with the Tenor chip Kingwa decided to use so that's another story. Let's just say that from three USB cables I have there is only one that lets the interface to connect in asynchronous mode to my PC. When it does, the result is nothing short of amazing.
 
First of all- coming from the Pico the Parasound had extremely realistic timbre. I know that Currawong did mention this in one his DAC reviews- the D/AC-1600 excels in portraying music in a very realistic manner. The rig I use consists of a second revision HD650 and a self-made Dynalo complete with a Joshua Tree 128 step relay-based discrete attenuator and a Sigma 22 PSU. I know of people calling the Gilmore design dry, cold and very analytical sounding but I can say that my Dynalo sounds anything but that. I have compared it with a Beta 22 and with both amps volume matched I found the Dynalo to be less aggressive and maybe a tad less resolving. In my opinion it is a perfect match to the HD650. Both of these devices are really smooth sounding, some might say- forgiving. The D/AC-1600 sound signature perfectly complements my Dynalo/HD650 rig. After some weeks of listening I will say that it might not be perfectly neutral. In my opinion it emphasizes bass a little, not much of sin with open headphones. Also the Parasound does treble in a very polite manner- it doesn't try to impress you with fake detail by emphasizing treble. I wouldn't use this DAC for reference purposes but for everyday music it's nearly faultless. It might not be the best setup for aggressive electronic music where more crunch and bite is needed, but it doesn't make the mistake of sacrificing resolution for musicality.
 
I'll conclude by saying that despite boasting big names in its parts list this DAC isn't high end (and never was). However if you can live with its limitations and size then it's a hell of a deal for 300 bucks. Especially if you take into account that it can do true balanced and you could improve it substantially by modding the output stage. The biggest price one has to pay when choosing this DAC is convenience, not money. Heck, I'm just happy that I have a set of rare digital chips if I ever decide to make my own DAC. I'm pretty sure that this DAC will never win any measurement contests, but what counts is that it has a type of distortion that never stands in the way of my music. Will, it work for you? It might and if worst happens then just sell it for the same cash you bought it.
 
UPDATE

After some surgical intervention that involves completely amputating the MOSFET output buffer I finally may have tapped into what this DAC has to offer. Also I realized how foolish it was of Parasound engineers to use the previous buffering solution. After installing the OPA134 with a BUF634 in the feedback loop the DAC came alive with improved soundstage, more controlled bass (the bass with the MOSFET buffer was pretty flabby and exaggerated). The next mod most likely will be modifying the digital filter.

As someone already had stated- the Grado SR80i gets left in the shadow of its less costly sibling- the SR60i. For me the choice was quite easy- I had a hundred bucks to burn for my first serious headphone, so SR80i was the best thing that I got in my sights. I had heard that the SR60i is a great performer and the SR80i should be all that plus more- the choice was easy.
 
First thing that I liked about them even before listening was the cable- it was nice and thick about the same diameter as a normal AC cable. When I looked at the grills it was apparent that if needed the resoldering should be a breeze. The 1/4 to 1/8 adapter is the most solid I've ever seen- when plugged on it seems like a natural extension to the plug. Other than the wire build quality seems sufficiently well, construction is light so these headphones won't break if dropped. Just try not to step on them. When reading about the Prestige Series Grados one thing did upset me- many people complained about the comfort. For my average sized head the clamping isn't too much though sometimes after longer (4+ hour) listening sessions my pinnae seem to press through the stock foam pads. But after a little rest it's all good again. I don't have very thick hair but the metal band pressing on top of my head was never a problem.
 
Now about the sound. First of all these headphones do benefit from burn in for about 50-100 hours. When listening for the first time my jaw positively fell in my lap but now I'm confident to say that at first they sounded a bit thin and harsh. After the burn-in they get a bit more gentle and the bass blooms too a little. Bass wise they are a little too tame though you can hear the stated 20Hz low end and it will be more than enough to get that great PRAT for rock and jazz. One thing you must keep in mind when feeding these phones- as higher end headphones sound terrible when not properly amped, these sound terrible when fed with the wrong records. The SR80i absolutely hates the loudness war. If you dare to listen something compressed you WILL feel like in a war! Your teeth will clench and you will tire and think about running to the hills. When I first listened to some of recent pop-rock I felt like fighting. Since then I've listened to just about everything Steve Hoffman has laid his hands and ears on. For some time I thought that from now on I won't be searching music by artists but by audio engineers. But there are many others who aren't sacrificing dynamic range for fast sales. And those are the ones a Grado listener must have. You must keep in mind that Grado is (in)famous for tuning his products to his ear, so in some sense your taste must match to his. The SR80i does not have the wide genre bandwidth of some closed phones or IEM's but when at it's best it sure does not sound like 99$.
 
The SR80i is a higher fidelity headphone in sense that it does not try to cater everyone. It IS a highly polarising headphone and that is visible to anyone who has read more than a few reviews. If you like to listen to 60's rock, blues, jazz, funk these might be all that you need. The sensation is closest to using a guitar amp for a pillow.