It seems like these days there is a frustrating dichotomy in the digital audio player (DAP) market:  you can either get a cheap mass-market player or a hyper-expensive boutique player with nothing in between.  Questyle’s QP1R digital audio player attempts to split the difference, offering top-tier build and sound quality at a price that sits in between the two extremes.  How successful you consider their endeavor will depend on your priorities in a DAP.
 

 

[size=20.007px]The Sound[/size]

 
Questyle (pronounced like “quest style” without the second “st”) is known primarily for their patented Current Mode Amplification (CMA) technology.  I’m no engineer so I won’t attempt to explain what that is; there’s a great write-up on the Questyle website if you’d like more information on it.  I have heard several of their desktop amplifiers using this technology and the upshot is a very powerful yet smooth amplification.  At flagship levels, their systems are so smooth as to seem delicate, like sashimi that melts in your mouth as you eat it.
 
I’ll just get this out of the way up front: CMA has made its way into the QP1R and it sounds very good.  This little device is eye-opening in its ability to drive full-size headphones with power and grace.  I can think of no better example of this than the finicky Sennheiser HD800.  
 
It’s no secret that the HD800 is notoriously picky about its source chain.  When driven poorly, its harsh treble and weak bass make people wonder why anyone would like it.  Properly driven, however, the treble smooths out and the bass fills in, making it one of the best sounding headphones on the market.  The QP1R has no problems with the HD800.  In fact, the current mode amp’s smoothness complements the HD800 well, leaving us with a well-controlled sound completely lacking harsh peaks.  And at maximum gain, it has enough headroom to get much louder than I’d ever listen to comfortably.
 
This same story continues with all the other transducers I’ve thrown at it, from IEM’s to full-size over-ears.  Power to spare with smoothness is the name of the game.  One minor thing to point out about this combination is that on already-smooth headphones, I sometimes found myself wishing for just a bit more energy.  But I’m going to chalk that up to my sonic preferences.
 
You might wonder how something powerful enough to drive things like the HD800 does with IEM’s or portables.  Well fortunately the QP1R has a three-way adjustable gain setting.  This is a great addition that lets you get a comfortable volume level no matter what you’re using.  
 
This leads me to my first real negative with the device, however.  With very sensitive IEM’s, even at low gain, you can clearly hear the background hiss of the noise floor.  I only tried one IEM that was distractingly sensitive (the Empire Ears Spartan-IV), but once you hear it, you can’t unhear it.  I started noticing it on my less sensitive IEM’s as well, even though I hadn’t noticed it at first.  While this is nowhere close to a deal-breaker for me, if your primary use will be driving IEM’s, it’s something to keep in mind.
 
Behind the stellar amplifier is the Cirrus Logic CS4398 DAC chip.  It gives you 24bit/192kHz maximum resolution as well as native DSD64 support.  This is the same well-regarded chip you’ll find in DAP’s of all price ranges, including one costing $2500.  Implementation is key as the performance varies in different units.  In this unit, the DAC is clean and detailed, complementing the amp wonderfully.  
 
If I had to nitpick, I’d say that it can sound too digital for my tastes in the highs.  This is a symptom of all Delta-Sigma DAC’s and some are worse than others.  If you’re not a user of R2R/multibit DAC’s, you probably won’t even notice.  As I’m a pretty big proponent of R2R, I find that it can be a bit distracting at times.  The similarly-priced Astell & Kern AK100ii DAP uses the same DAC chip and it sounds much less digital up top.  But that comes at the expense of ultimate detail as the AK feels softer than the Questyle.  It’s a tradeoff and I think most people who aren’t R2R fans will prefer the crisper Questyle.
 
Overall, the sound of this DAP is top notch.  Not only does it have a high grade DAC chip, but it has an amplifier to put most other DAP’s to shame.  This has it punching well above its weight when it comes to sound quality for the price.  And while some may find its lack of balanced output to be a negative, I think it’s just the opposite; you can get the full benefit of the great amp without investing in expensive cable upgrades.  Compared head-to-head with the AK100ii (in SE mode), the QP1R is more authoritative and much cleaner sounding on all but the most sensitive IEM’s.
 

 

The Build

Anyone who’s seen any of Questyle’s products in person can tell you that they’re about more than just the sound:  they exude quality and style.  The QP1R is no different.  
 
The body is machined out of a single piece of aluminum and sandwiched in between Gorilla Glass on the front and back. All the edges are beveled and there are no sharp edges on the device at all.  The ridged volume knob on the top is big enough to use easily, yet protected from accidental use by protrusions meant to be reminiscent of a watch crown.  All of the ports are recessed and the controls use both physical and capacitive buttons.  It has two microSD ports and 32GB of internal storage, allowing up to 288GB of music.  It has both digital and line out options.  To top it off, the whole thing is made at the same Foxconn plant that assembles iPhones.  
 
Yes, at first glance, this is the poster child for what a quality DAP could be.  But spend a little time with it and some cracks show in the facade.  There are two outstanding issues with the build that must be addressed.
 
First, the USB port is recessed in such a way that half of the USB cables I own won’t fit in the slot.  Questyle provides a cable that works great, but what happens if you don’t have it handy?  I don’t know about you, but I have USB cables all over the place and I just grab one when I need it.  If I have to keep track of one specific cable for one specific device, it kind of defeats the purpose of a universal standard like USB.  Fortunately, I have a few cables that work with it and I know what to look for now so I can spot which ones will work right away.
 
Second, and this is kind of a big one, the scroll wheel control is not nicely ridged like the volume knob.  It’s so smooth, in fact, that your finger will slide along the surface without turning it and you’ll have no idea what’s happening… or not happening.  I couldn’t tell at first whether the scroll wheel was broken or the software was laggy or what.  No matter the cause, the effect was frustration.
 
Eventually I learned to work around it.  The capacitive buttons help a lot and the scroll wheel does eventually break in and become easier to turn, lessening the frequency of slide incidents.  In addition, I know Questyle has a clear applique you can add that helps this.  And I’m told licking your thumb gives it more traction, though I’ve never gone this route with my review unit.
 
It’s not a deal-breaker by any means.  But it’s something to be aware of because it can cause some frustration if you’re not expecting it.
 
Aside from these two nuisances, the build quality and style of this unit is superb.  It feels good in the hand without being too big.  I think it looks stunning in “space grey” while others prefer the gold.  Either way, it’s hard not to like the looks.
 

 
[size=20.007px]The UI/UX[/size]
 
I’m going to say a few words about the User Interface and User Experience here because I think it’s an important factor for a device like this.  Your expectations and needs will play a large role in how much you like the UX with this device.
 
First, it boots up relatively quickly, which I like.  The AK100ii takes two to three times as long to boot up and I find myself leaving it on longer because I don’t want to deal with boot-up time.  Unfortunately that affects usable battery life (play time) so it’s something that is more than just an annoyance for me.
 
The screen itself is pretty small compared to the size of the unit, and the resolution is certainly good enough but not amazing.  The menu system is very simple and straightforward, letting me get to my music quickly and with minimal fuss.  I’m a big fan of these menus as I don’t tend to mess around with playlists or favorites or anything like that -- I pick a folder and play my music.  Those who prefer more elaborate options may want to look elsewhere.
 
The impression I get from the interface, both the software and the hardware to control it is “minimal”.  To me that’s not a bad thing.  It serves two purposes, the first of which is controlling costs.  This device is relatively cheap for as good as it sounds.  To get the price that low, concessions have to be made elsewhere.  The second reason “minimal” is good is that it really keeps the focus on what the device does best:  play music.  No frills, no fancy distractions, just a music player that does its job really well.
 

 
[size=20.007px]The Good, The Bad and The Pretty[/size]
 
The Questyle QP1R is a device that’s laser-focused on doing one thing well: sounding good.  If that thing is your priority in a DAP, you won’t find a better value on the market.  If you have other priorities, you may find it tantalizingly close to your ideal player, but not quite there.  Either way, there’s a lot to like about this gorgeous device.
 
For a first attempt at a DAP, Questyle has succeeded beyond any reasonable expectations.  While there is room for improvement, the QP1R is a stellar option at its price point.

If you’ve read my review of the ZMF x Vibro mk II, you’ll know that I enjoy ZMF Headphones.  I’ve had a review Omni unit for some time now and I’ve been procrastinating writing this review because, once it’s complete, I’ll have to return it!  But the time has come to put my thoughts down for all to see; your enjoyment will make me feel better about the whole “returning it” thing.  
 
Oh, if you did read that review, you’ll also have a great amount of background on Zach and ZMF so I am going to eschew that section of this review and just jump into the relevant stuff.  
 

 
[size=20.007px]Relevant Stuff[/size]
 
The Omni is ZMF’s current flagship headphone.  Some people will tell you that it’s a heavily modified Fostex T50rp planar dynamic headphone.  But that doesn’t really do them justice.  It has custom wooden cups, new ear pads, new headband straps and pads, new attachments for the cups, all its internal wiring replaced, and other magic modifications.  There’s so little of the original headphone left that I’d prefer to say that it’s based on the T50rp.  
 
As with all ZMF headphones, the Omni can be customized in many ways.  The most obvious will be your choice of wood.  Zach offers it in cherry, walnut and blackwood; he also has seasonal specials where he’ll offer limited editions in rare woods.  Besides changing the looks and weight of the headphone, the wood choice will change the sound a bit.  Some people tend to get really hung up on this choice so I’ll go into the sonic differences a bit later on.
 
The construction on these is solid wood, thick metal and sturdy leather.  While I can see someone worrying about dinging the softer woods, overall these are a very rugged headphone.  This is reflected in the weight, of course.  The Omni line ranges in weight from 480g to 600g.  The blackwood is the heaviest and I found that I got used to it.  In fact, wearing the lighter Omnis after the blackwood feels odd, like it will fall off if I sneeze.  I guess brain burn-in works on more than just sound! (For the record, no Omni has yet fallen off my head from a sneeze.  Trust me, I have a cold while writing this, so I’ve had plenty of time to test that aspect of the build!)  
 
The weight will obviously be a turn-off for some people.  But if you can deal with it, the Omni is a comfortable headphone.  The cup pivot system that Zach created for this headphone allows a much better fit with no fiddling, compared to older system.  It’s so good that he’s ported it onto his other models now.  The earpads are deep and cushy so they should fit anyone with no problems while allowing a seal with minimal fuss.  And the headband pad and strap distribute the weight nicely so there are no hot spots that can cause pain during long listening sessions.  The leather and pleather ear pads (there are options for both) can trap heat so that’s something to consider for those in the warmer climes.
 

 

More Relevant Stuff

 
Sonically, all ZMF headphones share a common lineage.  As you may have read in my Vibro review, Zach unabashedly tunes his headphones to make them sound great with acoustic instruments, which apparently means boosting the bass.  The Omni is no different in this respect; it’s bass-heavy and proud of it.  If you’re looking for a reference-level balanced tuning, this won’t be the headphone for you.  But if you want something that will make an upright bass or acoustic guitar sound like it’s right next to you, you’re definitely in the right place.
 
The bass is one of the special aspects of the Omni, especially the blackwood variant.  The wooden cups shape the bass into a large, all-encompassing entity.  And I mean that literally:  it feels like the bass surrounds and defines most of the spherical soundstage.  Almost every other sound is presented within the bass rather than alongside it or layered above it.  But unlike some other bass-heavy headphones, the bass never intrudes into the other frequencies.  The mids and treble are presented with clarity despite the potentially booming bass.
 
It should come as no surprise then to read that the bass extends well into the sub-bass regions and presents a rumble that’s hard to match.  I’m not one to really differentiate “impact” and “slam” and some other qualitative bass terms.  I’ll just say that as a planar, the bass hits hard with a very detailed feel.  Yet it doesn’t feel thin like some planars because of the resonance provided by the wooden cups.  It’s a great trick and I think bassheads will appreciate these headphones.  
 
The other star of the show with the Omni is the detail retrieval.  This is a flagship headphone with commensurate pricing ($899-999 for the standard wood models) and the technical performance reflects that.  
 
My main rig for some time has been the Hifiman HE-560 and Cavalli Liquid Carbon.  The 560 is priced comparably to the Omni and at one time I found the performance to be about on par, with the Hifiman giving a more balanced presentation but with a lighter and cheaper-feeling build.  However when I upgraded to the Cavalli Liquid Crimson, a much more powerful and resolving amplifier, it became clear immediately that the Omni outscales the HE-560 by a good margin.  It’s capable of retrieving much more micro-detail, making the HE-560 sound a bit fuzzy in the same way the HE-560 did to my old mid-fi dynamics.  The Omni loves power and the more you give it, the more it will give back.
 
The Omni, as I’ve mentioned is bass-heavy, but that doesn’t come at the expense of the other frequencies.  The treble is crisp and snappy with no bothersome peaks, and it’s adequately extended.  I have a track that I use to test treble extension and on a headphone with rolled-off treble you simply can’t hear the hi-hat during the verses.  The Omni does not have that problem.  You should note that the treble too is affected by the chosen wood and I’ll address how shortly.
 
The mids are not notably bad or notably good.  They’re well done and, more important, they’re not recessed.  I heard a pre-production model that had some small weirdness in the mids, but Zach promptly fixed that issue for the final tuning.  In fact, the entire frequency response feels very natural other than the lifted bass.  Because of that, the Omni can really work with many genres where some basshead cans tend to be more one-dimensional.
 
The Omni is a semi-open headphone, meaning it’s mostly closed but has some openings.  This gives it a best-of-both-worlds feel in some respects.  The bass benefits from the closed aspects, with its big, heavy feel.  The treble, on the other hand, benefits from the open aspects.  The soundstage extends out quite a bit further than the other ZMF models (which are all closed).  The treble actually extends a bit outside of the sphere delimited by the bass, which can be a little odd sounding on tracks with lots of bass.  On more balanced tracks, the discrepancy isn’t noticeable and you just get a nice big soundstage.  
 

 
[size=20.007px]Relevant Aside[/size]
 
Here’s the most important thing you need to know about the different wood choices: they all sound far more alike than different.  Unless you’re listening to them back to back, you’re going to have a hard time noting the differences.  Pick the lightest one or the sexiest looking one or the one whose sonic characteristics seem the best.  If it turns out you don’t like the one you got, you won’t like the others either.  Remember, all the models are tuned to the exact same frequency response.
 
As I described in the Vibro review, the hardness of the wood affects the sonic presentation and the weight of the headphone.  The harder woods are heavier and tend to have chunkier bass and sharper transients.  The softer woods are lighter and tend to have more decay, softening the bass and the transients.  I like to think of it as a scale from 1 (soft) to 10 (hard).  Cherry is a 1, blackwood is a 10 and walnut is a 5.  The exotics tend to fall on the in-between numbers.
 
**Now I’m going to get into very subjective territory here so take this bit with a grain of salt.  Remember:  my preferences may not match your own, so keep that in mind when I talk about which I like best.**
 
I find that the blackwood is the most technically proficient model.  It’s got the cleanest presentation with the most detail.  It also has the biggest, chunkiest bass, which I found a bit over-the-top until I got used to it.  Now that I’m used to it, I think the bass is one of the special aspects of the Omni and I’m happy to get as much of it as I can.  I don’t know if I’d like it as my only headphone though.  Oh and it’s the heaviest.
 
It’s worth noting here that the blackwood is $100 more than the other models.  This is because the wood is simply more expensive.  In my very subjective opinion, it’s worth the extra money.  I know that not everyone who has tried multiple models back to back has agreed.
 
On the other end of the spectrum, you have the cherry.  This guy is quite a bit lighter than the blackwood, which is very welcome.  The bass is still there and still big, but it’s a bit bloomier.  The treble is also a bit laid back compared to the blackwood, letting the mids breathe a bit more.  Overall, it’s a more relaxed sound, which, when combined with the lighter weight, makes for an easy listen over a long time.  
 
The walnut tends to be right in the middle in all respects.  This is a very safe choice, but while you might think it’s a best-of-both-worlds proposition, I personally feel like it’s actually the opposite.  You don’t get the technicality of the blackwood but it’s still on the heavy side.  I realize this is just personal preference though.  I’m what video gamers call a min/maxer; if you know what that means, you’ll understand my opinion here.
 
I won’t go into the specifics of any of the exotic woods.  They’re not always readily available and Zach always likes to surprise us with new choices.  Anything I talk about now might never show up again.  Suffice it to say, you can tune your experience a bit with the exotics.  Want something almost as technical as the blackwood but with a tad more decay and less weight?  How about something as light as the cherry with just a bit more edge?  Whichever you pick, they all look amazing.
 
At the risk of sounding like a broken record, I want to stress again that all these woods sound like an Omni.  You can’t go wrong with any of them so decide which most appeals to you on paper and just go for it.  
 
Anyways, very subjective section over.  Now back to normal levels of subjectivity.
 

 

Relevant Coda

 
The Omni, like all ZMF cans, excels with acoustic genres like bluegrass and jazz.  Counter-intuitively, it also rocks with electronica thanks to the wonderful bass.  Unlike other ZMF cans, however, the Omni is very good with most every genre I’ve listened to on it.
 
The ZMF Omni is a the culmination of everything Zach has learned making headphones -- it’s the best headphone he’s ever made.  It outperforms other similarly-priced headphones, with looks to match.  I highly recommend folks give this headphone a listen and don’t skimp on the amping if you want to hear it really sing.  I think you’re really going to like it.
 
 
Note:  All impressions were with review units provided by Zach (@zach915m).  I’ve had a good amount of time with all three standard wood models, as well as the exotic Black Limba wood (shown in the photographs).  Thanks to Zach for being so accommodating!
 
Listening impressions were mostly with the Audio-GD DAC-19, Cavalli Liquid Carbon and Cavalli Liquid Crimson.  Cables were variously stock and upgraded cables sold by ZMF.

 
 
I have a confession to make: for a long time, I didn’t think of modded T50rp headphones as “real” headphones.  I found it odd that people could modify a cheap headphone and sell it for hundreds (or even thousands!) of dollars.  But then I listened to a few and realized that there may be something to this after all.
 
Here’s the thing: these mods are often extensive including completely replacing the cups, the internal wiring, and even sometimes modifying the driver itself.  They are done by hand and custom built to order.  And the sound can range hugely from extremely dark to painfully bright, with something for everyone’s taste.  There are several major modders and each has their own style; you can’t really guess at the sound of one just because you’ve heard another.
 
Now I’ve heard some of the T50rp mods and I was duly impressed by what could be accomplished with this humble headphone.  However, I never heard any that really spoke to me; they were good but not for me.  Would the ZMF Headphones be my flavor of choice?
 
The Company
 
ZMF Headphones is owned and operated by Zach Mehrbach, with help from his wife.  Zach’s headphones are most obviously differentiated by the use of wood to replace the stock plastic cups.  The wooden cups were designed in conjunction with Luke Pighetti at Vibro Labs.  And no, it’s no coincidence that the model being reviewed is called the ZMF x Vibro; Zach credits Luke with doing a lot to help the success of these headphones.
 
Less obviously, ZMF is differentiated by their individualized approach.  You’re not getting a mass-produced unit made in China.  You can order your headphones in multiple colors or stains, with powder-coated or anodized metal sliders, different earpads, different headbands, different cables, and even custom tuning.  Since he uses real wood instead of laminate over a composite, each unit has its own unique grain and texture.  The headphones that I was sent for review even included hand-written, laminated certificates of authenticity.
 
This individualized approach truly makes each headphone unique and gives them a feeling of quality; it feels like you’re getting your money’s worth.  I think we’ve all had that moment when we wonder exactly how much some of those multi-thousand dollar flagship models actually cost to design and manufacture.  With these units, I don’t ever get that sneaking suspicion that I’m getting taken for a ride.
 

 
 
The Build
 
One thing you will never hear about ZMF headphones is that they feel cheaply built.  You get real wood that’s hand-stained to order in Zach’s workshop.  The headband is made from the thickest rubber I’ve seen outside of a tire shop and covered with supple leather padding.  The metal bars that connect everything look like they could hold your TV to the wall.
 
This Vibro is the mark ii version and it sells for $429.99 at the time of this review.  Recently Fostex discontinued the T50rp MK ii, which was used in the original Vibro, and replaced it with the MK iii version. While updating the design to work with the new driver, Zach took this opportunity to revamp the Vibro.  He brought in several of the improvements from his more recent headphone designs and they’re welcome indeed.
 
The first changes are to the mounting system.  The attachment point for the metal bars is lower on the wooden cups, and the mounting hardware offers significantly more range of motion.  This change translates into a marked improvement in the fit of the headphone.  On two previous units I tried, I found the fit to be a bit finicky; one unit was be just right and another wouldn’t seal properly.  With the new setup, I get a perfect fit and seal every time (I’ve tried it on no less than 5 units at different times) and I’m happy to say it alleviated one of my biggest problems with the original Vibro.
 
Another change is that the new Vibro has a special channel for mounting the ear pads.  Zach makes three kinds of ear pads and they each offer a different flavor to the sound.  This is great unless swapping pads is too difficult.  Though not perfect, the new system is a notable improvement.  It also cleans up the visual lines and looks better.
 
Some might be concerned about the weight of a wooden headphone, and rightly so.  I’ve used several ZMF headphones and some of them are quite heavy.  The weight depends on the wood used and I’m happy to report that the wood in the Vibro is actually quite light relative to the rest of the line.  I don’t find the weight (approximately 435g) to be an issue at all with this model, especially when some manufacturers have headphones weighing over 700g!
 
As with all ZMF models, this uses a double-entry mini XLR cable, similar to the ones used by Audeze in their LCD line.  That means it will be easy to find after-market cables if that’s your thing.  You might not need to though.  The cables that come with the Vibro are thick and feel high quality.  Even better, there is an upgraded cable available that uses Double Helix Nucleotide OCC litz wire.  The prices for the upgraded cable range from $99-149 and, since they’re hand-made at ZMF, they too can be customized.  Unless you’re looking for some crazy silver-cryo-unicorn-tear cables, these will be sufficient for most folks at a very reasonable price.
 
There is also an option for a hard case to protect your headphones when on the road.  These seem to be built like a tank and I really didn’t think it was needed.  However, Zach sent me a demo unit that had travelled around and asked me to take it to a show with me.  When I told him I didn’t have room for the case he said it was fine.  So I threw it in my bag and off I went.  But when I got home, I noticed that the soft wood was dinged here and there.  I realized that as sturdy as these are, the wood is still susceptible to visual damage.  If you want these to stay looking great, the hard case is a smart investment.  It’s made by Seahorse in the USA and works well.
 

 
 
 
The Sound
 
Zach tunes his headphones to what he likes, not a calculated average of what everyone else likes.  It so happens that Zach plays guitar and banjo and was at one time a luthier.  As such he loves listening to a lot of acoustic music, especially bluegrass.  That strongly informs the ZMF “house sound”.  These headphones are tuned to make acoustic instruments, especially stringed instruments, sound as real as possible.
 
I highly recommend you look up something like “The Boy Who Wouldn’t Hoe Corn (live)” by Alison Krauss or “Sakura Sakura” by the Stanley Clarke Trio with Hiromi.  Zach’s headphones’ sonic signature excels at genres like bluegrass and jazz and these tracks really show off their strengths.
 
As it turns out, getting acoustic instruments to sound this good means pretty impressive bass levels.  I’ve spent a good amount of time with every ZMF headphone, including all three varieties of Omni.  The first thing you’ll notice about any of them is the copious amounts of bass.  In the case of the Vibro MK ii, that’s still the case, but it’s not as in-your-face as some of his other products.  I think it’s the most balanced sounding of all his headphones.
 
The bass is full and impactful, and it doesn’t feel particularly emphasized in any frequency.  The closed wooden cups give the bass a resonance that reproduces acoustic instruments wonderfully.  As with a nice guitar, different wood types can change the resonance and nuance of the various models, while still retaining a similar overall sound.  My review Vibro MK ii is made from red walnut, which is a soft wood and doesn’t resonate as much.  This suits my tastes well but if you’d like a bit more bass presence, maybe consider a harder wood.
 
To be clear, the bass is still boosted, giving it a warmer than neutral sound overall.  But being a softer wood, this model doesn’t have the bass-head levels of chunkiness that you can get out of something like the blackwood Omni.
 
As this is a planar magnetic headphone, when driven properly with enough power, the bass is very detailed underneath the resonance.  It’s almost a best of both worlds situation: detailed, impactful planar bass underneath the bloom and decay typical of a dynamic.  This helps it feel like the bass isn’t bleeding into and recessing the mids.
 
Speaking of the mids, they’re probably the next thing you’ll notice after the bass.   Vocals are a pleasure and acoustic guitars are phenomenal.  Throw on something like “Diamonds on the Soles of Her Shoes” by Paul Simon if you really want to hear those mids sing.  The layered vocals from Paul’s high voice to the African choir’s deep bass are intoxicating.  There are many acoustic instruments layered in there too, which these headphones love.
 
The treble is smooth and inoffensive without feeling veiled.  There’s enough of it there to give these headphones a very large soundstage for a closed can.  I’ve heard some very well-regarded open headphones that are so warm that they sound more closed than these.  And the extension is actually quite good.  I like to use the 2004 remaster of Megadeth’s “Skin O’ My Teeth” to test this because they pushed the hi-hat way up in the range where headphones with rolled treble can’t even reproduce the sound.  I was pleasantly surprised to realize that this warm headphone doesn’t have that problem.
 
And again, as this is a planar headphone, the treble is fast and precise.  It’s an interesting counterpoint to the bass with all that resonance decay and it helps keep the headphone from feeling too warm.
 
As I said earlier, the Vibro MK ii excels at genres like jazz and bluegrass.  But thanks to its sound signature, which I will call more “natural” than “balanced”, it’s also completely competent with most anything I’ve thrown at it.  Songs with prominent vocals should sound great.  Electronica, hip-hop and dance music all work well, as you might expect with that big bass.  On the other hand, the big bass means that genres with fast crisp bass, e.g. modern metal, aren’t going to be at their best.
 
“But Dan,” I imagine you asking your screen, “if these are so great, why bother with anything more expensive?”  Well, I say to you having successfully predicted your question, of course there are flaws.  The bass doesn’t extend as far into the sub-bass as some of its big brothers.  The detail retrieval overall doesn’t match the more competent Omni or Blackwood.  If you were to listen to the two back-to-back you’d hear that the Vibro simply isn’t on the same level as the Omni.
 
But you’d also hear that it’s very close to the Omni for about half the price.
 

 
 
The Last Word
 
If you can’t tell, I'm enamored with these headphones.  They’re closed and they’re warm and they’re colored, all things I don’t usually like.  Yet, they have such a pleasing, musical sound that it just doesn’t matter.  As I’ve been reminded often lately, this hobby is supposed to be about the music, not the gear.  ZMF headphones with a competent R2R DAC connect me to acoustic music in a way that’s unique in my experience.
 
As with anything in this hobby, diminishing returns means that a headphone that costs nearly twice as much doesn’t give nearly twice the performance.  If you’re been reading about how wonderful the Omni is but don’t want to spend that kind of scratch, you owe it to yourself to try out the Vibro MK ii.
 
 
_{Big thanks to Zach (@zach915m) for the review unit and his infinite patience!}

Not too long ago, I was a lowly noob looking for my first headphones.  I waded through the murky waters of terminology I couldn’t understand and brands I’d never heard of before.  Over time, some patterns started to emerge and I started getting an idea of what the community considered bad (I’m looking at you, Beats) and what they considered good.
 
Of course Head-fi is a very diverse community so I rarely saw a product or brand that everyone could agree on.  But one brand name that was always spoken of with respect was Cavalli Audio.  The Liquid Gold was arguably one of the pinnacles of summit-fi audio.  Even if nobody could agree that it was “the best”, the fact that people argued about it at all says a lot. 
 
Time passed and I became educated, as we are all wont to do.  My ideas of what was considered sane pricing for audiophile equipment changed, but Cavalli amps were always out of my price range and thus off my radar.  Owning a Liquid amp of any kind was as far away as owning a $30,000 Sennheiser Orpheus.  Until one day, this little fellow was announced.
 

 
The Liquid Carbon is a small transportable, solid-state, balanced amplifier that was designed to be an entry point into the Cavalli “house sound” at a reasonable price.  The limited first run of 500 units is selling for $599.  While this is still quite pricey in some ways, it’s less than one quarter the cost of Cavalli’s next cheapest amplifier.  It’s a full 90% cheaper than the Liquid Gold was when it was released!
 
Obviously, many people were excited right away at the prospect of Cavalli sound and quality in an affordable package.  Then CanJam SoCal 2015 happened and people got to hear it for the first time, including myself.  It was pretty unanimous that this was a great sounding product and a bargain at the asking price. 
 
Pre-orders went on sale and hundreds were reserved on the first day, just based on impressions from CanJam!  But production would take four months and people have been ravenous for any more impressions on the unit.
 
I spoke with Dr. Cavalli after Canjam about using his amp in an upcoming project for Head-fi (more on that to come) and he graciously provided me with a pre-production unit to use until my final unit is ready.  I’ve been using it for some time now and, due to popular demand, I’m here to give you a preview of this wonderful little device.  While I don’t have a ton of experience with different amps, I’m going to do my best to deliver those sweet, sweet impressions that we all need so badly.
 
The Boring Stuff
 
The unit I have, as I mentioned, is a pre-production unit so a description of its physical properties is not going to be particularly helpful.  Suffice it to say, the unit is very small and light and is indeed quite transportable.  It also looks very classy in matte black with a laser-engraved logo.
 
On the front panel are outputs for XLR and Kobicon/RSA balanced connections as well as ¼” TRS single-ended.  There is a power switch, a gain switch and an input selection switch.  The final unit will also have LED’s to indicate… stuff.  The back panel has the power cord input, XLR balanced inputs, and single ended inputs via RCA or 1/8” TRS.
 
Do note that purchased units will not come with a power cord.  These are intended to be high-end audiophile units and those folks tend to be picky about their cabling.  Dr. Cavalli can keep the price lower by not offering a cable that many folks wouldn’t use anyways, so it seems like a win/win to me.
 
The Good Stuff!
 
Okay, whew, glad we got all that out of the way.  Now we can get to the juicy bits, namely how it sounds.  To sum up my thoughts in one trite sound bite: it feels transparent and detailed like a solid state, while imparting some of that warmth and euphonic tone of a tube amp.
 
The amp is very transparent in that is has a wonderful black background as well as the speed to provide enough detail to satisfy my planar-magnetic headphones.  I did the IEM test at one point:  I plugged in my Noble 4 CIEM and, with no music playing, cranked the volume until I could hear some hiss.  It was apparent at about 12:00 on the knob.  However, it should be noted that normal listening volume with the IEM’s was at about 7:10 on the knob (with 7:00 being the starting point).  12:00 is absurdly, damagingly loud with a sensitive IEM.  So you can imagine that at normal volumes it’s just dead silent.
 
I also found it transparent in another way:  the soundstage.  While it wasn’t the widest soundstage of all my amps (the NFB-28 is notably wider), it has a wonderful sense of front-to-back depth that the Audio-GD lacked completely.  I never noticed that the NFB-28 felt unnaturally wide and flat until I compared it to the LC.  In fact, the Liquid Carbon has a very proportioned soundstage between the X and the Z axes giving it a very spherical presentation.  Something about that nice shape makes it just feel natural, which in turn adds to the feeling of the amp just getting out of the way.
 
Now tonally, I’m going to say that it doesn’t actually sound perfectly “flat” to me.  It’s got an added weight to the bass and a bit of a laid back treble.  Neither of these effects are particularly overstated, but they’re certainly noticeable in a direct comparison with other amps.  Slight as the warmth is, this can certainly affect the pairing with some headphones, so it’s worth keeping in mind.
 
Interestingly, I find that it also has some of the euphonic characteristics of my tube amp, the Garage1217 Project Solstice.  The bass and mids have just a bit of bloom, not in that “not enough power and control” sort of way, but in that “what has two thumbs and loves that tube sound” kind of way.  I know it’s a weird thing to say that this solid state amp sounds tubey, but there it is. 
 
The warmth and euphony that this provides is wonderful; it gives the amp an effortless, fatigue free sound that you can just listen to for hours on end.  When combined with the transparency and detail mentioned earlier, it makes for a potent cocktail of audiophile bliss.  If this is the Cavalli house sound that people are raving about, I can certainly see why!
 
Some Nerdy Stuff
 
I’m also going to touch on something here that I’ve discussed previously on Head-fi but is worth restating.  The amp uses something called a phase splitter to convert the single-ended input into a balanced signal before sending into the actual amping circuits.  Now, I don’t claim to have a clue what that means from a technical perspective.  But the intention, as I understand it, is to make it so that a single-ended input signal benefits from the fully balanced amplification circuits.
 
I tested this myself to see what the big deal is.  I plugged my balanced DAC, the Theta DS Pro Basic II, into the Liquid Carbon both via balanced XLR and single-ended RCA.  Then I used the handy button on the front of the unit to swap back and forth between inputs.  They sound virtually identical.  Since the labeling of the button is a bit unclear to me (probably more a failing of mine than anything else), I actually lose track of which I’m listening to because they sound exactly the same.  I have to unplug one of the connectors from the back to tell.  It’s as close as I’m going to get to a blind test and the LC beat me every time. 
 
To be clear, the phase splitter makes it so the SE input sounds as good as the balanced input, all other things equal.  It’s a very interesting feat and it opens up all kinds of possibilities for DAC pairings when you’re not limited to balanced DAC’s for the best sound.
 
One last caveat:  I haven’t tested this with any other DAC’s as the Theta is my only balanced one.  It’s possible that the Theta just sounds the same balanced and SE, and all the phase splitter is doing is matching the volume.  I think more testing is in order and I look forward to seeing what happens when the greater community gets their hands on the LC.
 
The End (for Now)
 
I hope this brief preview gives you a better idea of what to expect when the Liquid Carbon is released in a few agonizingly long weeks.  It pulls off a wonderful trick of being linear and detailed, yet musical and euphonic at the same time. While it sounds oddly schizophrenic on paper, it actually adds up to a synergy that works effortlessly. It’s a sound that doesn’t leave you wanting for more detail, yet never fails to be musical.  This could very well become the mid-fi amp to have for audiophiles who want it all at a reasonable price.
 
Equipment used in this preview includes:  Theta DS Pro Basic II, Audio-GD DAC-19 10^th Anniversary Edition, Audio-GD DI-2014, Garage1217 Project Solstice, Schiit SYS, Hifiman HE-560, Noble 4C, ZMF Blackwood, ZMF x Vibro, Oppo PM-3.  Source was my PC running Foobar to play a variety of MP3’s and FLAC’s in genres including rock, metal, djent, trance, dance, psybient, trip-hop, jazz, hip hop, and a sprinkling of classical.

Oppo PM-3 – Entry Level Luxury
 

 
 
Intro and Background
 
Entry-level luxury -- this term may seem like an oxymoron, but many people realize that even entry-level luxury can be a significant improvement over the best of the rest.  As it is with the BMW 320i or the Nikon D3300, so it is with the Oppo PM-3: top-tier quality and performance at a manageable price for mere mortals.
 
Oppo made a big splash last year with its PM-1 and PM-2 headphones.  They had the full package:  great sound quality, great build quality and great looks.  The PM-2 even had all this at a great price.  They showed that you can have your cake (great sound) and eat it too (great looks and quality).  They raised the bar and already we’ve seen Audez’e responding with the EL-8, a new design that’s better looking, sturdier, and priced to compete with the PM-2.
 
Oppo has now released the PM-3 and is looking to take another big step away from its competition, who is only just starting to respond to the last Oppo.
 
The Basics
 
The PM-3 is a closed-back, portable, planar-magnetic headphone priced at $399 USD.  There are few choices of planar headphones in this price bracket, none of which are both closed-back and portable.  Its main competition at this price point comes from portable, closed dynamic headphones like the Sennheiser Momentum, Focal Spirit Pro, etc.  But of course, comparing a dynamic to a planar is not usually an apples-to-apples comparison.
 
I won’t bore you with technical specs on this headphone.  Just know that, being portable, it’s fantastically easy to drive.  I have no problem driving it off my phone, from my DAP, from my PlayStation controller, etc.  Driving it off my big amp is trivial…I have the volume at 4 out of 80 during quiet evening listening.
 
When you buy these headphones, you also get a really nice carrying case.  The ear cups on the headphone pivot 180 degrees so you can lay them flat (on the front or back side).  This makes them really “neck-able”.  It also allows Oppo to make the case nice and slim, which is great for a portable.  It’s very easy to slide into a computer bag or backpack without creating any uncomfortable bulges.
 

 
Also included is a 3m cable (with a fun little baggy to hold it) and a 1.2m cable.  There are options for the 1.2m cable without a remote, with an Android remote, or with an Apple remote.  I believe you choose which you want when you order.  As I have a loaner unit, it came with all three.
 
The PM-3 has a removable cable, which attaches via a 3.5mm TRS connection.  I’ve found that the V-moda cables (including the Boom-pro) work well, as does a cheap Monoprice cable that I had lying around.  This is great news, since the cables that come with it are nothing to write home about.  They get the job done, but they’re somewhat thin and the rubber on the wire has enough friction to make it a pain to try and detangle.
 
The ear pads are not user-replaceable.  However, they are replaceable by Oppo.  This was done in order to give a better seal for bass response.  I think it’s a fair compromise, though some may not.
 
Don’t let those last two nitpicks get you down though.  Overall, this thing just exudes quality.  It’s got a fair amount of metal, and the plastic parts are very high quality.  It’s stylish and understated with just a hint of bling -- in a word:  classy.  In order to get that kind of quality at a low price point, something’s got to give.  If the included cable isn’t to your liking, it’s easily replaceable and there are plenty of high end cable companies making alternatives.  You’ll certainly be able to afford it with how cheap the PM-3 is.
 
Comfort
 
I find myself somewhat torn on the comfort part of this review.  You see, sometimes I find them uncomfortable but most times I completely forget they’re there.  I’ve worn them for hours on end at work or in the evening gaming and really felt no fatigue.  Yet, sometimes if they’re not sitting just right, they can be annoying.
 
I attribute this to the smallish earpads.  The circumference is on the small side, so my ears are always touching the inner wall of the pads.  They’re also deep, but very soft and marshmallowy.  This means they have a tendency to touch your ear to the foam protecting the driver.  Neither of these are necessarily bad, but if it’s not sitting just so, it can be bothersome.  Once you find a comfortable spot, though, it’s easy to forget they’re on.
 

 
 
I find the weight to be heavy enough to be “not light” but light enough to be “not heavy”, so right in the middle, I guess.  The headband is well-padded and comfortable, so the weight isn’t burdensome.
 
The clamp can be a little tight.  I’ve found that if you extend the ear cups a bit lower than your first instinct, it makes the clamp less forceful.  I have also read that you can stretch them to relieve the clamp, but as this is a loaner unit, I chose to avoid that.
 
Sound
 
“Yeah, yeah, great, but how does it SOUND?”  Well, dear reader, it sounds good!
 
Overall, it sounds like a slightly brighter version of the PM-2.  It has the Oppo house sound, which is a mid-forward sound, slightly on the warm side of balanced, with a laid back treble. In this case, the bass and mids are very neutral and the treble is slightly laid-back, which gives it that warm feeling without sounding particularly dark (i.e. bass-emphasized).  I’m a big fan of this sound as it’s just so easy to listen to for long sessions.  It’s a very smooth, musical sound that will appeal to a lot of people.
 
The treble is, as I mentioned, laid back.  Yet it doesn’t feel particularly rolled-off.  It’s not veiled like the HD650 or innocuous like the LCD-2.  It’s there, just… smooth and fast enough to give good imaging and separation.  The treble is definitely south of neutral, which give it that laid back sound, but that laid back sound also detracts from the airiness and soundstage, which I’ll get to momentarily.
 
The mids are the star of the show.  Up front, musical, and just great with anything I’ve thrown at it.  To me, they’re as good as any of the greats like the HD650 or the PM-2.  Not much else to say; they’re quite good.
 
Bass is, to me, the biggest draw of planar magnetic headphones.  What we expect to hear is bottomless bass with detail and control like you’ll never hear in a dynamic.  Impact and body are almost always there, though quantity can feel lacking to those who are used to a more boomy, pronounced bass.
 
The PM-3 has that extended, bottomless bass.  It has a fair amount of impact and body for a planar (I’m sure helped by the fact that it’s a closed-back design).  But that body also gives it a little bloom, which detracts from that super controlled and detailed bass that I’d expect.  It doesn’t bleed into the mids at all, though. 
 

 
Interestingly, I don’t think it’s a bad thing.  It sounds closer to dynamic bass, while still being very detailed and extended.  It’s almost like a best-of-both-worlds kind of thing.  I will caution that these are in no way bass-head cans.  Those who aren’t used to planar bass might find these to be a bit bass-light until they let their brain burn in for a few days.
 
Now we get to my least favorite part of the write-up:  the soundstage.  It is the one major weakness of these headphones.  In short, it’s small, even for a closed headphone.  I have a strong preference for open headphones with a big soundstage, but we all need closed cans once in a while.  I understand that there are tradeoffs.  But even my current closed headphone, the SoundMAGIC HP100 has a notably bigger, airier sound.  It’s going to be a major turn-off to some folks, and that’s the real disappointment.
 
Despite the small soundstage, however, these headphones still manage to image and position quite well.  That planar speed lets even the small soundstage have separation between instruments.  It never feels congested.  And that’s the saving grace; if you can deal with the small soundstage, you’ll find that it’s not a bad sound like most small soundstage cans.
 
If I had to pick one headphone that these compare to the most (that’s not made by Oppo), I’d say the Sennheiser HD650.  While the smaller soundstage is obviously going to be noticeable, otherwise the sound balance is very similar.  However, the PM-3 is planar so the bass is more detailed and far more extended.  The treble is also missing that “Sennheiser veil”.
 
The Bottom Line
 
I like these headphones.  The sound is pleasing, smooth and easy to listen to.  You get a taste of planar speed and control, without having to shell out the big bucks.  It’s easy to drive, sturdy and looks fantastic. 
 
The catch?  Somewhat lower quality cables, the fit can be a little picky, and the soundstage is on the small side.
 
I think those trade-offs are very minor considering what you get for $399.  This headphone gets my enthusiastic recommendation to anyone who is considering it.  And I will put my money where my mouth is:  I’m buying a pair of these to be my “daily driver” at work.
 

 
 
One More Thing…
 
I’d like to extend my heartfelt thanks to Oppo Digital for making the loaner program available to us.  Thanks to the hard work of @Jiffy Squid, I was able to test the Oppo PM-3 at home for a week and I’ve thoroughly enjoyed my time with it.  As of the posting of this review, the loaner program is still available HERE and I highly recommend you avail yourself of it if you’re on the fence at all.