PSB M4U 1

This has been called beats for audiophiles. It has great sound, is neutral and detailed, but they are glossy and fairly fashionable. In general, I like a V shape and listen to hardcore, metal, metalcore, so treble and bass add a more lively sound. This headphone does not emphasize those without an EQ. I have the DT770 and UE6000, as well. Those are ultimately better for the genres I listen to if left without EQ, but the PSB's are more detailed and can be EQ'd through Poweramp or other software.
 
A big plus for these (at least for me) is the replaceable cups, 2 detachable cords, and the hard case. These even come with an extra set of cups, which is awesome if you damage yours.
 
There is a clamp to them, but it is light. They will stay on your head at the gym, unlike the UE6000's, which have a lighter clamp and tend to slip off.
 
I have not heard the ATH MSR7's, but these are consistently rated higher. The only reason to look at the MSR7's is possibly that they don't look as goofy as these. These are attractive stand alone, but they are just so big.
 
I would also add that the DT 770's have a wider sound stage, with better musical separation. That has to do with the huge cups, I believe. These don't have that, but comparably are still damn good sounding.
 
Got mind on Ebay for $137. $230 new

These attractive 'phones are a mixed bag for us. The bright red color is certainly distinctive. Build quality, while mostly shiny plastic, feels fairly robust. Many aspects of their sound are truly outstanding, but (and it's a fairly BIG but) they simply aren't comfortable for extended listening sessions. Since everyones' head and ear shape is obviously a bit different, as is their tolerance for discomfort, these are a pair that should be test-worn at length if possible prior to purchase in our opinion. The price point these fall within puts them up against some very serious competition from the likes of Grado, Sennheiser, AKG, Denon, Sony, and many, many others.
 
Now--the good stuff! Bass response in our highly-optimized system is nearly beyond reproach, with admirable pitch definition, dynamics, and extension down well into the 30hz range, which is partly due to the excellent seal of the cups against your ears, as well as the substantially-sized drivers. Sensitivity is middle-of-the-road, fairly easy to drive. Most popular portable devices shouldn't have trouble pushing the PSB's to acceptable volume levels. Moving on to the midrange I find nothing noteworthy to complain about, with the M4U1 exhibiting suitable neutrality as to not draw attention to themselves (that's a major compliment). The treble region isn't devoid of defect, but is smooth and certainly less 'tipped-up' than for example, most Grados. If you're a soundstage and imaging nut though, in our rig these had a VERY wide throw, giving that uncommon 'outside-of-your-head' sense with real instrument placement in space, along with a good sense of depth. This, to our ears, is probably their most striking trait and compares favorably, at least in that regard, with models from other manufacturers selling at much higher prices. As usual, YMMV, but these are well worth a good listen before plunking down your hard-earned dollars. If they're comfortable enough for you, then you have a definite winner.

***Others have provided ample images / specification overviews, so my review is focused on convincing you to try these out, with some comparisons to headphones in and out of its price range.
 
A 5 Point Scale – 1 being Bad, 5 being Excellent / Industry leading
 
Design and accessories (4):
 
The combination of gloss plastic and metal bits are “modern” and while they are still a bit too chunky to look truly “cool”, they are a far cry from ugly. No squeaky parts or creaks out of the box, and the folding mechanism is useful. The Cables are obviously a tad budget, but they are flexible and good lengths – though the right angle connectors are clearly not for home amp use (but work just the same). The cables don’t snag at all however, a big plus, and I can move them from the L cup to the R cup if I please, a really nice feature.
 
The included accessories, travel case and spare pads are real nice to have at this price point, and certainly make me feel more comfortable with the idea of traveling with these if desired. Highly efficient, I wouldn’t hesitate to use them with my phone or computer – they are easier to drive than my HD-595s, which have much higher impedance swings. They play much louder on these typical devices than my HE-400s, which are nearly 10 dB less efficient. I imagine users of iPods and other dedicated players would have no trouble with the PSB M4U1’s. My Sansa Clip sounded plenty loud, though midrange sounded a tad nasal and bass and treble lacked the same presence. Ultimately, these sounded their best out of a dedicated amp - but my O2 is total overkill as the PSB's need well under 1 good mW to get real loud.
 
My first pair of used PSB’s arrived with a blown R channel and a lot of signs of wear and tear. The second used pair arrived with original packaging and appeared flawless (hopefully just a “didn’t like it” return), so I do hope these prove to be reliable and well made. I doubt they will leave the house much if at all, but I’ve violently dropped my other headphones and so I expect these to take some punishment too! Hopefully the 2 year warranty will not be needed. In short, an attractive, and far more “complete” package than many headphones available at similar (and much higher!) price points. Additionally, these seem very well made - I fear the internal wiring as a possible "weak point" in these, but otherwise they seem well constructed.
 
Fit and Comfort (4):
 
The most controversial part of my initial impression, I am dissenting from other reviewers to emphasize that these have become far more comfortable with daily use – to the point that I can wear them for an hour or more without any obvious pressure points or fatigue. As my first pair of closed “audiophile” cans, these seem to have relatively high clamp force – not painful, but I am aware of it. The ear pads are probably at the absolute minimum for what I would call “circumaural” – though they do measure similarly to my HE-400s and HD-595s, the former being round, the latter a more extreme oval shape. My ears are fairly small, though it seems they’ve fit fine on the heads of some kids and another adult. The memory foam feels nice, though they get warm relatively quickly. I do prefer velour 90% of the time, if only because it breaths and overall tends to be more comfortable for longer listening sessions. Memory foam is, as a general rule, hard and cold in the winter and smooshy and hot in the summer, so it would be nice to see manufacturers pursue better, more consistent materials. I swivel the cups around to spread the pad pressure better (they don't seem to "self-adjust"), and have had no issue maintaining a good “seal”.
 
Cup depth seems to be minimal as well, placing the drivers close or against my ears, and I believe that is what causes me some listening fatigue. That or perhaps the sound pressure of having such a tight seal and small cavity, I am not quite sure which. As I have gotten more used to these, that issue has relaxed somewhat. My HE-400s have never been ideal – the velour pads are hard, and the headband creates a pressure point on my head (I feel the headband bearing more of the weight, and the clamp force is lighter by comparison after having bent it a tad). But the pads have always been of a good depth and the seal has tended to not be a problem. The HD595s are superior in all comfort respects, soft velour pads with slightly more generous clearances, and light weight that never really fatigues in my experience. They are, however, more sensitive to placement – the sound can shift a bit depending on their position. Were the PSBs lighter, and if they used velour pads, I am sure they would become more comparable to the Sennheisers.
 
After a longer listening session, I am typically breaking the seal of the PSBs or trying to slightly shift the “racetrack” pads around looking for a little relief, but once these are on there is not really “wiggle room” so while they feel secure they also come across to me as slightly claustrophobic – they just never truly disappear. I think it would be helpful if the “gyro-scoping” cups were a bit looser, to make finding the right angle easier.
 
As I am used to open-backed headphones, the added isolation is somewhat new. I would find it dangerous for outdoor listening (one should be able to hear what is coming at them, SQ be damned). I do like the way it almost kills the sound of the fan blowing on me and computer whirring, however, for quieter listening sessions. Low-tech noise canceling is certainly a nice thing for home use. But while I can listen and converse with my open-backed cans on, I can’t do that with these. Not a big deal, but a point to make.
 
Sound Quality (5):
 
Without question the sound quality of these phones is probably the finest I have ever heard. I assumed I wouldn’t like the “warmth” of the NAD HP50s (slight tilt toward the bass and smoother treble), or the higher price and tight fit of the Focals which are similar to these, and I think I made the right choice. These headphones can really punch, are extremely detailed, and possess the best upper midrange / treble I’ve heard on a pair of headphones, hands down. The basic character of the headphones seems to hold at very high / painful volumes, not something I can say about all the headphones I’ve tried. That suggests to me very high sound quality with good dynamic range and low-distortion.
 
I made my assessment in a number of ways, jumping from Tablet / Phone devices to my O2/ODAC setup, and running all manner of music from Pandora to Spotify, to High-Quality Mp3, FLAC, and CDs. I never used any EQ. Typically once I “get to know” a headphone’s sound, I might EQ them to render out any problem areas I feel I’ve found or to just suit my mood. I should be clear in noting that, while these sounded very good out of my Phone (currently a Lumia 640), and a Nexus 7 Tablet, in comparison to my O2/ODAC, both devices took on a slightly more mid-centric sound – I think bass punch and treble extension were both dampened by the “inferior” electronics (quite true of many headphones, I would add). The sound quality of the PSBs would likely seem less sublimely “balanced” or impressive to the casual observer if only heard ONLY in this way. If you are not using a good amp with your pricier headphones, know that you are likely missing out on the best sound they have to offer. Modern devices sound great in my experience, but they still lack that extra bit of amplification quality that can be had relatively inexpensively. The “easy to drive” flat and low-impedance of the PSB’s is, unfortunately, not a guarantee that they will sound optimal with today’s typical devices. But in a pinch, these have a far more valid claim to being "efficient" than the HE-400s, which are only adequate on the same devices.
 
To describe sound quality I will mention a few albums here and there, but my collection is large, and I won’t bother commenting on all of it except where I felt it might be worthwhile. Suffice to say, I didn’t find a genre that the PSB’s couldn’t do justice – these would be a first choice for classical, and they work great with jazz as well (a usual first test for detecting flawed speakers). Modern recordings sound punchy and energetic, without tending toward harshness, and these headphones can “party” with the best of them. With their inherit balance they won’t “hype” the sound any further than it may have been hyped at the recording level. If you are new to headphonia, understand that this is a very good thing in the long-run. I’ve not felt an urge to do anything other than boost the bass from time to time, which straddles the “lean/perfect” line for me on occasion and recording-depending. Then I find myself listening to them again and wondering why I would change anything – they are that good.
 
The headphones may be “closed”, but the sound is not. Call it PSB’s “roomfeel” if you want, but certainly these impart a sense of depth and space that is just lovely. Gorgeous treble pours forth from these with refreshing ease, cymbals finally splash instead of “tsst” to my ears, and the sense of depth and air is fantastic and permeates the bass, midrange, and treble. Insofar as a headphone can do it, these sound very “open” to me, with good channel separation and a fairly wide stage. The midrange called attention to itself immediately, with gorgeous vocals in particular grabbing my ears. Lead singers and their backups were clearly delineated with a light “airiness” between them. The quality of the midrange has helped me to once again peer into my old music collection marveling at all the “new sounds” I can hear. It is a very seductive midrange to my ears reminiscent of my Pioneer Andrew Jones speakers. The treble adds to the listening experience rather than sizzling or disappearing behind upper-midrange heat. The balance here is always smooth and detailed, and the PSB’s certainly come far closer to sounding like an “ideal” full-range speaker to my ears. I’d make a small note that crowd clapping, a sound I felt only my HE-400s really resolved in Bill Bruford’s Earthworks The Sound of Surprise album, was convincing on the PSBs. Sounds moot, perhaps, but that is a big testament to the resolving power of these headphones –not many I’ve heard sound like something other than static. I could almost count the hands, and heard exactly what they were yelling. Yup, I think they actually beat the planars on that note, having the resolution, neutrality, and probably speed to flesh it out.
 
Bass is excellent in all respects that matter (texture, punch, tone, extension), but I still felt it was a bit of a sticking point. While these punch great when the recording calls for it, and they have obvious extension, I’m not 100% sure I’m in love. I hear excellent tone and good texture, particularly with some Jazz music I tried (indeed these rival the HE-400s which are Jazz masters in some respects). “They hit all the notes” to borrow from a guy named Moe who was an audio genius when I was a kid. While no headphone has ever sounded like a “real speaker in a real room” to me, the HE-400s do, in my opinion, generate a more convincing “sub bass” feel, particularly on electronic music. Perhaps the combination of a great sound with the tacit feel is what is missing in the final equation for all headphones. Don’t get me wrong, the bass of the PSB M4U1 is excellent, and well balanced with the quantity of bass probably right on the money for my tastes, but planars just seem to do it better –a little more punch and a tad more convincing in the regions below 60 hz or so. Perhaps a larger driver would improve on this comparison (40mm is large, but sometimes there is no replacement for displacement). As part of the big picture, however, I find little complaint here, it is a simple fact that my planars reach another level of bass quality.
 
My recent adoration for Joss Stone’s Water for Your Soul shined on the PSB’s – they peered into the recording in a way the HE-400s and HD-595s could not. From the opening moments of the intro track “Love Me” the balanced presentation struck me as providing a relaxed and yet finely detailed performance. While the bass punch, texture and extension place these ahead of the HD-595s, they lack that last bit of refinement that I feel I hear with the HE-400s. But where the HE-400s come across as a bit “dark”, the more balanced presentation of the PSBs provided, to me, a more exciting and informative top end – the HE-400s notorious “treble peak” was clearly a few dB too high, while the PSBs rendered instruments and backup vocals more faithfully without coming off as “hot” in comparison.
 
The HD-595s deliver, to their credit, a very similar sound, but the same sense of detail and “depth” in the recordings was ultimately not there, and they lack the same detailed and fleshed out treble. Both the bass and treble sounded rolled off, and Joss’s vocals were to larger extent blended with the backup singers. It is a “forward” sound without the richness, resolution or added texture of the PSBs. The 595s ultimately did not deliver the same ultimate clarity, punch, textures, of depth. But the sound is still a comfortable one, and I can still listen to these for hours. It is just that the Senn’s simply never truly “come alive” like the PSB or HE-400, the term I might use is a bit of a “papery” sound in back-to-back comparison. If this is what “listening comfort” is, I suppose I’d rather suffer some fatigue than settle for a less engaged sound.
 
 “Love me” on the HE-400s had a rich and textured bass line. Vocals were better than the 595s, but the slightly pumped “tsst” treble was distracting – clearly a few clicks too high, and vocals were well resolved but a tad flat sounding. If the PSB sound like a “good room”, the HE-400 sounded like a “dead room” – any sense of air or “reverb” is suppressed. They continue to deliver on the Bass with a good “punch” and similar, if not more convincing extension. “Space” and “air” are not on display, despite being open-backed. I should note that I did my listening with velour pads, which are better than the stock pleather by far, but did not EQ, which typically improves on the sound of these meaningfully – bringing the treble into better balance.
 
While the PSB’s revealed a bit of the over-hot “hisses” and “clips” of some albums, like on Norah Jones’ Little Broken Hearts, it was ultimately a tad more forgiving than the HE-400s while less forgiving than the Sennheisers. It was here that I wondered if the Oppo PM3s, being very similar to these but using a planar driver, might add the last bit of resolution that the PSB’s seem to not quite achieve. Had I not already invested $400 in the HE-400s, I am certain those would probably add resolution to the balanced performance of the PSB’s that would be simply gorgeous.
 
Lana Del Rey’s newest CD Honeymoon was not an enjoyable first listen in my car (component Polks + a JL/Audiomobile subwoofer system). While her vocals were on full display, they seemed to hang high above the orchestral and mixed beats, with a preference for reverb/resonance largely “muddying” the sound on my imperfect component set. Pacing was slow and while I never get tired of her voice, the album as a whole seemed oh-so-boring. Not being one to let my first impressions rule, I looked forward to listening to it on my PSBs, and on my (as of 9/20/2015) sorbathane-modded HE-400s. The album became a rich and intimate experience. Something about the “balance” of the album seems off, the musical arrangements pushed ever so slightly too far below Lana’s vocals, or maybe the bass lines are too “stretched out” and slow, making the pacing unusual for a “pop” album. But despite the sorbathane curing the HE-400s of their glare and resonance problems (which add fatigue and a sense of “clutter” particularly to the midrange), it is on the PSBs that I feel I had the best moments with the new album.
 
Where the HE-400s now sound like they run out of steam in the treble, the PSBs resolved it all, and proved once again that Lana is more than just another pop princess, she is a real talent. The whole album is in many ways a more consistent ride than her previous works – I can enjoy every track over and over. I’ve been on a hip-hop kick lately also, and aside from commenting on mastering quality / bass quantity, I find that the PSBs make it a smidge easier to actually follow the lyrics. Bass “slam” is largely a wash, though I can make the HE-400s have a much fatter bass sound with a slight boost in the 50 hz area. Both phones are great, but probably a tad lean sounding to those who might ONLY listen to hip-hop / dub-step, and other bass heavy genres. But to sum up, I can't find much fault with the PSBs, at all. They are sublimely balanced but not boring at all, on the contrary, they are extremely satisfying. It would seem that only a planar driver or perhaps a slightly better damped ear cup could take the sound to a higher level. But even then, do we want resolution and the recording blemishes that will probably go with it?
 
Movies and Gaming (4):
 
Movies certainly sounded great on these, as expected. The main issue being a question as to whether I could wear the headphones for 2 hours or longer, and I think not really. But then again I would tend to use headphones only as a last resort, or if using a device. The Winter Soldier has a great scene where Cap America single-handedly wipes out a boat full of hostage-taking terrorists. I heard things I’d missed before, like the sound of his shield clanging when he rolled on the boat deck. Details like that make me appreciate the thought that goes into movies. That ability to really hear deeply into the sound effects is interesting, as with movies the visual feast is usually my focus as a passive snacking spectator.
 
Typically any headphone that renders music very well is going to handle games just fine – and certainly I find these to work very well – I could pick out the Nazis in the distance with ease and dispatch with extreme prejudice. But given that movies and music tend to have higher dynamic range than “pop” music, you will find yourself twisting the volume dial quite a bit more. In fact, this is a reason why movies and games, along with classical music, tend to benefit the most from big amps with plenty of “headroom” – the volume swings essentially require it. I should note that while the “neutral” sound of the PSBs works great for gaming and movies, I found myself fondly remembering my HD-485s, which had a much bloomier bass that was lousy for music but always sounded awesome with films and games. A few more dB of bass would make the PSBs a better match for the hyped sound of modern games and action movies. Mainly, I can’t give them a “5” in this respect as having better comfort would go a long way to making them a great companion for today’s 2+ hour movies.
 
Conclusion: So Close to Perfect (17 / 20 = 85 = B)
 
What I don’t like about these phones has nothing to do with SQ and everything to do with my suspicions about comfort and build quality issues. Having gotten more comfortable with wear, I must ding the PSBs for being a little imperfect in that sense. Having worn other headphones without major comfort issues I recognize room for improvement. Were I to rate the Sennheisers and HE-400s I compared them with, the mix of SQ / comfort / design issues would probably put them both at solid “C”s or so. If I could have only one, the PSBs definitely “win” the overall, the sound quality largely trumping other issues. I bought these primarily because of curiosity about the Sean Olive / Harmon Curve and Wirecutter reviews. I know that a solid neutral sound is typically going to be close to an “end game” sound, in the sense that it will tend to flatter all music genres and is the right ideal to strive for (the basic best practice for speakers was settled decades ago, headphonia has tended to be a “wild west” IMO – with manufacturers producing headphones without knowing necessarily what to strive for). The headphone world is replete with sound signatures that function, in my opinion, like mechanical EQs that drive a lot of us nuts. The PSB M4U1’s, as a first take on a new approach feels like a giant step in the right direction, and puts a lot of pressure on “high end” headphone makers to consider what kind of sound should be possible at any price. I am so confident in the sound quality of these that I would put them up against the most expensive headphones in the world, and expect to still prefer access to this sound – discussion of “pairings” to amps and “cables” be damned. How about an open-backed version of these, with velour pads and fewer accessories for $200? Count me in.
 
Yet I am still on the fence about the M4U 1’s in some respects. They are clearly aimed at a “mobile” user in terms of design / accessories, yet they make good use of a “desktop” audio setup (and need one for absolute best sound IMO). They are certainly efficient enough to not require a big amp, my O2 at 2.5X gain is total overkill (and I don’t feel like going to unity gain just for these but may need to). On the other hand, one is definitely not getting the best sound without a device that has a solid amp, and most don’t. On the basis of overall Fit, Finish, and Comfort I wouldn’t really want to pay more than the $200 I got these for – they just doesn’t quite scream “premium” to me. To be extra critical, I would pay far less – maybe $100. Ditto for my HE-400s. If Sennheiser can get comfort right with virtually every pair of them I’ve put on at low prices (that lovely “barely there” feel and solid construction and attention to detail), surely it can be done cost-effectively by others. Primarily I would improve the comfort with slightly larger and deeper pads. I would offer a straight plug and reduce the weight – these are not what I consider “heavy” but they are not light either. Clamp force could probably be reduced a tad and they would still seal just fine. Angled pads might actually spread pressure a bit more ideally, as the cups themselves have a limited swivel range (and 2 axis of travel despite claims of “gyro” movement – the vertical travel was stiffer). Get me a Sennheiser-like fit with this sound quality, and I have a headphone that I could use all day long without an issue. Because believe me – I want to use these all day long.
 
Like the HE-400s the sound quality of these headphones forces me to forgive most of their sins. These are probably flagship-beating headphones in that respect, sublimely neutral but with good speed, energy, and resolution. They are fun to listen to, easy to drive, and can be cranked right up. In fact, these are the sort of headphones I find myself wanting to notch up all the time, something to watch out for. If these are what good speakers sound like in a good room, than I have no question we have got a thousand dollar sound here, which is exactly what I love about headphones in the first place – they can, and should be, the cheapest, best hi-fi one can get their hands on. At $200 (I bought used), they are a steal SQ wise. For $300 asking, the price of entry is steeper and competition is fiercer, and I am unsure I am willing to put down that sort of money considering how satisfying I find my Pioneer speakers to be, and 2 bookshelves and a sub were a mere $200, and that is a very nice sounding full-range setup. To be fair, the PSB’s are available online typically for $250, which is probably a fair price.
 
As a step-up, I am sure the Wirecutter is spot on recommending the Oppo PM3s – after hearing these, I can only imagine how beautiful the planars with a similar sound signature would sound. Were the comfort also superior, it would be a no-brainer. But alas, my HE-400s were my first $400 pair of headphones, I am not sure I am prepared to put up that kind of coin again, considering the strong sense of guilty regret I experienced! When and if the Oppo’s become available for a little less ($200-$300), I would probably pounce on them with no hesitation. The Harmon-curve, even in its “beta” phase, is no joke, and these PSB M4U1s, like the NADs and Focals to which they relate, are all perhaps some of the highest value headphones on the market right now, and an easy recommendation for those interested in sublimely-balanced high quality sound.

These headphones are a steal for the msrp price (don't mind that I got a killer deal).
 
I haven't heard any headphone come close to achieving the textures achieved by the PSBs.  The chunkiness of Ska guitar, the ring of brass, the resonance of string orchestras, etc.  These headphones handle a large number of music genres with ease.  They also miraculously make lossy format music bearable to listen to.  Female vocals kill it with these headphones,and despite being a bit on the warm side, there isn't any bass bleeding into the mids.  Treble is present, clear, almost bright but not quite, and never sibilant.  Mids seem a bit forward, but not to the point of drowning out the bass or treble.  The detail and imaging are there, despite the small-ish sound stage (in general, for a closed-back these have a decent sound stage).  I used to use these as my "go-to" headphones for everything, and when I was jacked into my PC, people could scare the dickens out of me by walking up to my on my workstation.  I took these on plane rides with positive results considering there isn't active noise cancelling.
 
However, they aren't perfect.  I find the ear cups a bit small, and they feel a bit uncomfortable after some time.  You also feel the weight of the headphones after an extended listening session.  After having listened to AKG open-backs, I've spoiled myself on sound stage. This also opened a can of worms for me, as the sound stage on the PSBs are a bit small for my taste now.  You could definitely see this shortcoming in gaming, and as such, I couldn't recommend it for that purpose.  The bass is solid, and as someone sensitive to boomy bass, I really like PSB bass.  However, it does lack the extension and impact that some of my other cans have.  This last point is a minor, as it's a fine line between good impact and boomy for me, and the PSBs are on the safe side of that equation.
 
Overall, great headphones.  Not something I'd recommend for a bike ride or exercise in general, but amazing for travel and home listening.

PSB M4U 1: A New Standard is Born
 
 
 
 
 
 
 
Intro
    
    I am quite sure that many of you, myself included, have started on the seemingly never ending path to finding the perfect set of headphones. Terms such as too bright or too dark, mid-bass hump and recessed midrange, peaky treble and accentuated sibilance, are enough to drive a sane consumer mad. Or at the very least an unnecessary waste of one’s hard earned money. There has simply been no frequency response standard in headphones, until now. In conjunction with their sister company NAD, PSB Speakers has set the new reference standard on how headphones should sound that not only faithfully reproduce the music, but is universally pleasing to all including the most demanding of listener. For a first attempt they sure got it right.
 
 
History
 
    Highly acclaimed for both performance and price, PSB Speakers has been an industry leader in the world of high-end loudspeakers for nearly 40 years. Realizing at an early age that loudspeakers did not sound too great, company founder and chief designer Paul Barton set out to design and build his very own loudspeaker in his family’s woodshop. It wasn’t long before Paul was selling his speaker kits to university students and in 1972 he and his wife Sue formed PSB Speakers. Two years later, with the help of the Canadian NRC (National Research Council), Paul’s psychoacoustic research literally changed the world of loudspeakers forever. His research determined how a loudspeaker’s frequency response curve should sound to faithfully and accurately reproduce the music as intended by the engineers of the recording. 
 
    Paul Barton’s on-going research and methods of determination are regularly used by not only PSB, but most high-end loudspeaker manufacturers to this day. Unfortunately, in the world of headphones there is no industry standard. Despite knowing how music is produced and how music is supposed to sound, no manufacturer has developed a transducer headphone with the same acoustic sound signature as the loudspeaker.
 
“ Nowadays speakers are much more consistent; They aren’t ‘black and white’, ‘day or night’ different, and if they are then they are rejected. So, I think headphones (in 2013) are in about the same state right now that loudspeakers were in back in the 1970’s. Because there is no agreement on what the ideal target response profile for a headphone should be. “
 
Paul Barton, Hi-Fi+ (Aug. 2013 excerpt) 
 
 
About me
 
    Growing up in a family consisting of musicians, broadcaster/sound engineers, and amateur DJs, I always had a deep appreciation and understanding of both music and sound. Beyond Elementary School ukulele, my interest was always been in appreciation rather than creation. I was further educated in this self interest after taking courses in both electronics and sound (electro-acousto); There are not many instruments I have have not stuck a mic in or around and sampled it’s waveform. While I believe a listener’s preference in sound is subjective, the science behind it is not. I am someone who, when a guest at someone’s home, takes it upon myself to perfectly calibrate their Home Theatre and HDTV by the time they return with drinks. I am someone who enters a noisy room and hears all the annoying noises that no one else hears. People I know call me first when needing knowledgable advice and opinion when it comes to computers and consumer electronics. I am not swayed by buzzwords, hype, trends, brand recognition, or big numbers on charts; I am the nemesis of the commissioned salesperson. Opinionated as I am, my words are not only objective but honest. I view all criticism as constructive, as long as it is sincere. All equipment in this review was decided upon and purchased by me. No company has sent me any of their products (though I wouldn’t turn them down), and nobody is endorsing me to write this review. 
 
    In all honesty, I never had an interest in headphones up until the past two years. To me, headphones were always more of a utilitarian device, used out of necessity. Beyond monitoring and the occasional gaming session, my use of headphones was limited to blocking out the noise of my daily travels. To me, listening to headphones while engaged in either music or movies was less than satisfactory; They simply could not compare to my hi-fi loudspeakers. The problem is not so much that I found headphones to be inadequate, rather I knew that if I wanted sound comparable to a good hi-fi system I would be needing to spend a lot more money than I was willing to. That is, until my work hours shifted to a later start time and I could no longer listen to my hi-fi system; Both my wife and townhouse neighbours would be fast asleep and unappreciative of me blasting my music throughout the dead of night. My work hours eventually went back to normal however I had fallen hard for headphones and was now in search of that perfect sound signature to compare to my WF-34 Icons. 
 
    Over the past two years I have gone through the gauntlet of headphone research; Buying, trying, selling, returning, auditioning, inconveniencing, and frustration are but a few words to describe my journey. I had been eying the M4U 1 since I first read about them back in 2013, however I had neither found a retailer with a pair on demo, nor did I actually find one that had them in stock. As a hi-fi guy, Paul Barton is my loudspeaker idol. I have been an admirer of not only his work but PSB Speakers for years, and the technology behind Room Feel looked incredibly promising. It certainly did not help my envy that popular review sites such as Innerfidelity and TheWireCutter raved about both the NAD Visio HP50 and the PSB M4U 1/2. In the end I settled for a few pairs of popular hi-end headphones. The deciding factor was not so much based off from one definitive reason, rather overall sound quality vs the low price I was able purchase them for. By a stroke of luck or impeccable timing, in late November of 2014 a popular nation wide electronics chain put the M4U 1 on sale for 50% off, and by chance my local retailer, one the first day of the sale, had one left. In fact, it was the last one available chain wide in all of Western Canada. My ride on public transit seemed like an eternity but in the end I came, I saw, I conquered! Fantastic!
 
 
PSB ‘Music For You’ : M4U 1
 
Headphone Specifications
 
Designed and Engineered in Canada, Made in China
 
 
Packaging and Accessories
 
 
    Upon pulling off the sleeve to the box, I really felt like PSB was providing me with a premium product. The box is made of 100% recycled materials and flips open like a book. Inside neatly sat the hard travel case which stored the headphones, with 3 bundled accessories bags located under the flap of the left tray. Included in first bag is a quality 3.5 mm to 6.3 mm gold plated adaptor, a universal airline adaptor which will greatly appeal to frequent flyers, a carabiner for easy attachment to bags or luggage, and a micro-fibre cleaning cloth. Unlike what most manufacturers provide, the cleaning cloth is actually of useful size and thickness; So often you get a small 45mm x 25mm piece of cheap polyester that is smaller than what PSB provides, folded up. The next bag included two headphone cables; One standard straight cable, the other with a one-button control-talk module that is guaranteed to work with at least iDevices and Blackberry phones. The last bag contained the extra set of leatherette ear-pads and replacement instructions. I can’t tell you how much this is appreciated as tracking down and ordering a replacement set of ear-pads can be a real hassle, not to mention unnecessary listening downtime. I also applaud PSB for including shaped inserts to prevent loss of form when stuffed in the case.
 
 
 
 
 
    All of the accessories fit neatly into the high quality, light weight, hard travel case and are held firmly in place by the mesh. Having traveled with the case attached to my bag via the carabiner, I can assure you that everything was held secure in place. Although not pictured, it is both possible and safe to keep the headphone cable attached when the M4U 1 is folded in the case. Simply put, all aspects of packing and travel have been smartly addressed.
 
 
 
 
 

Build, Aesthetics, and Comfort
 
    As expected of a company such as PSB, the M4U 1 are of high quality build and construction. Holding these in my hand, they do not feel cheap or flimsy, yet reasonably light. Multi layered thermoformed polycarbonate reinforced with ABS make up the bulk of materials used, ensuring both strength and light weight. Stainless steel extensions run down into the arms and are reinforced at the fold point with a metal plate, which is screwed on to the headband. The ear-cups are attached to the yoke via a brushed-stainless backplate which acts as an up/down pivot. In the centre of the backplate sits a chromed nickel PSB Speakers logo which also acts as the left/right swivel. Located on the bottom of each ear-cup is the 3.5 mm entry plug. The dual left or right entry plugs is a handy feature allowing you to not only daisy-chain another set of headphones, but alleviates the annoyance of either the phono jack or source equipment being on the opposite side of the cable. The stitched ear-pads as well as the head-pad are made of a very high quality leatherette. The material is very soft yet strong and if one did not know better, would swear it was real leather. The provided cables are decent enough. They are of good length, have no bad microphonics, and neither tangle nor have a bad tendency to keep their shape. Although I would have preferred that they would have made the cables a little thicker, it is not an issue as any 3.5 mm cable can be used. 
 
 
    Available in Baltic Grey, Monza Red, and Black Diamond (pictured), the M4U 1 sports a modern design. Despite the Monza Red sharing a similar shade as a certain unmentioned ‘fashion’ headphone brand, the M4U 1’s profile is quite elegant and unique. The finish is made up of multiple layers of clear polycarbonate which helps achieve a deep, glossy appearance. Unfortunately the camera does no justice in portraying just how sexy the M4U 1’s finish is; They really need to be seen in person to fully appreciate their look. A narrow grey strip running along the middle of the body helps break up the solid gloss finish. The brushed steel back plate and chrome insert adds additional contrast and is a nice throwback to old hi-fi equipment design, adding that last bit of prestige to overall look. Essentially, the M4U 1 will have no problem fitting in when placed next to a modern HDTV or hi-fi stereo system.
 
 
    Coupled with buttery soft memory foam ear-pads and the complete 360 degree axis of the ear-cups, obtaining a perfect fit should not be an issue. Having an average sized head and ears, the clamping force was sufficient to assure both a good seal and good grip, yet not overly tight with no unwanted and annoying pressure points; Once broken in, the ear-pads meld into the side of your head while still maintaining the proper buffer and cushion. Thanks to the wide arc of the headband the weight of the M4U1 is evenly distributed and never do I feel the full weight of 340 g bearing down on my neck. In terms of long listening sessions, I had no trouble wearing the M4U 1 for 4+ hours before I needed to take a quick break; Like with most closed headphones it was to alleviate and vent some of the heat build up, rather than discomfort due to fit.  Overall the M4U 1 remained relatively cool and after a while start to become invisible on your head. Be warned though, people with larger heads and ears may have comfort issues in the beginning, but much like a pair of new shoes the M4U 1 will loosen up after some breaking in.

 
    Despite being the passive variant of the highly acclaimed M4U 2 with ANC, the M4U 1 does an excellent job of blocking out unwanted background noise. Taking a walk down to the local convenient store, which is located along a busy street and multiple bus routes, it was impressed with how much noise the M4U 1 actually block; They are easily on par with custom fit ear-plugs. Although the included hard travel case and fold-up design means the M4U 1 is meant for portable use, in my opinion those features are meant literally for just that; Moving the unit from point A to point B with minimal hassle and packing as opposed to using them on-the-go in the urban environment. Nothing is going to stop you, besides the threat of looking like a Hipster, but due to their overall design they are mean for a more low-impact use. Fortunately PSB also makes the M4U 4 IEM which would be a better match for the urban warrior.
 
 
 
 
Value vs Quality

 
    PSB has been renowned and praised for their premium quality loudspeakers without the premium price, and the M4U 1 proudly carries that torch. If I were blind folded and had the M4U 1 placed upon my head with several tracks played, and then asked if the sound quality I just experienced warranted a $699 MRSP, I would have no reservations in saying yes. If instead I was asked if $499 was fair for the sound I just heard, I would agree that the M4U 1 are deserving of that price. At a MSRP of $299 PSB not only offers almost unreal quality and value for the price, but puts the M4U 1 in reach of the average consumer who want a premium sound, solid build, and plethora of useful accessories. By choosing to go with polycarbonate and ABS and outsourcing construction to China the savings were passed along to the consumer. Sure, PSB could have gone with more premium materials and had the units hand-assembled in Canada, but this would undoubtedly raise the total cost, potentially making the M4U 1 less attractive for those of us who may not be able to afford them otherwise. All of this is backed up by a 2 year manufacturer’s warranty.
 
 
The Sound - Basics
 
Click here for Head-fi’s interview with Paul Barton.
 
Room Feel Technology
 
    What is Room Feel Technology? Ever heard DSP or software based headphone sound space enhancers such as Dolby Headphones, SRS, or Razor Surround? Room Feel Technology is nothing like them. Music is recorded, mixed, and mastered in a room with two forward firing monitors. The key word here is ‘room’. Essentially the music you and I enjoy is meant to sound it’s best coming out of two flanking loudspeakers, in a ‘room’. So what is so important about the ‘room’? When loudspeakers pump out sound, only a certain percentage of the sound that reaches your ears comes directly from the cones. The rest of the sound is being reflected off the walls, floor, and ceiling. Without getting too technical, the room actually gives the sound energy, and while that energy predominantly affects the lower frequencies, it actually gives body to the whole frequency response. Without this added energy the sound loses it’s potential resulting in a rendering that is not true to the recording. Up until now, not a single headphone manufacturer has taken the ‘room’ into account, despite having very similar frequency curves to the M4U 1. Thanks to Paul Barton’s genius, the M4U 1 sound not like conventional headphones, rather sound like a really good pair of loudspeakers properly positioned in a room with you the listener sitting in the sweet spot.
 
 
First Impressions
 
    It is a lazy Sunday afternoon, nothing better to do you go down to your local hi-fi store with the intent of picking up some speaker wire and perhaps a CD or two. Being a slow day, the salesperson ushers you into a sound room and proceeds to give you the full demonstration of the store’s most expensive amplifier and loudspeakers. Having a decent hi-fi setup at home, you initially agree simply to indulge him only to emerge from the room having listened to quality of sound that you did not think was before possible. This scenario perfectly describes the M4U 1.
 
    From the moment I placed the M4U 1 on my head and pushed play, I was absolutely blown away at how bloody good they sounded, from a loudspeaker perspective. Though not for one second did I ever doubt the claims of Paul Barton and the Room Feel Technology developed by NAD/PSB, truthfully I was not knowing what to expect; A small part of me kept saying ‘Buzzword’ and ‘Overhyped’ every time I read ‘Room Feel’. All reservations went out the windows once I heard how clean, resolving, and BIG the M4U 1’s sound was. Initially the M4U 1seemed like it had a slightly warm tilt, but after further listening I soon realized this was not warmth I was hearing, it was full body across the whole frequency spectrum; Nothing sounded weak, distorted, coloured, or out of place. After playing the Headphone Dating Game over the years, this truly was love at first sight…or hear. 
 
The Experiment
 
    On Christmas Eve I had decided to bring my iPod and the M4U 1 over to my parent’s. It had been a little over one month since the initial purchase and while I had been impressed with their overall performance, I saw this as an opportunity to get a pooled opinion from both music lovers and professionals. Having all festivities take place downstairs in the rumpus room, I strategically placed the iPod and headphones on the kitchen table that everyone would need to pass on their way to the only bathrooms on the main level; New technology in my family is as enticing as a flame is to a moth. It wasn’t long into the night’s festivities before I heard someone say “ By the way, who’s headphones are those upstairs? “ and the talk turned to the M4U 1. Although it could have been “ PSB makes headphones? ”, out of a group of around 25 family members the top remarks were how ‘clean’ and ’natural’ the sound was, followed by “ These are how much? “. Most agreed that the vocals were some of the most natural and forward sounding they had heard in a pair of headphones; All agreed that overall, the M4U 1 put their beloved (and more expensive) headphones to shame.
 
    Normally I would blather off any and all information on the tech I am showing off before I hand it off. It was both refreshing and rewarding to get unprompted opinions from people who are well informed. I would like to conclude by saying that this time I had said absolutely nothing about the M4U 1 to my family either before or after their listen. Not Room Feel Technology, not their frequency response or impedance rating, not even my own personally feelings. Besides stating that the M4U 1 were made by PSB Speakers and that I had got them for a half-off, the only thing asked by me was in regards to their opinion on the overall fit and comfort level, which received no complaints.  My sneakiness and curiosity not only validated my own thoughts on the M4U 1, but every other review giving them high praise; Impressive for a first go!
 
 
 
Frequency Responce Curve
 
 
    First thing that I would like to disclose is that the above FR graph is a compilation, averaged from many sources found on the internet. I have no means of measuring headphone sound output, and did want to cut and paste an FR graph taken from another site. Instead I thought it would be better served if I compile and average the data pulled from both professionals and enthusiasts measurements. Although most of the FR curves for the midrange were consistent, there were two common variances I encountered in the bass and treble regions. The bass curve on some graphs displayed a steep shelf starting at 30Hz extending down to 20Hz, while other showed consistent curves yet the amplitude of the whole treble zone was about 5dB higher. Oddly enough, both variances were more common amongst enthusiast blogs rather than websites of a more professional nature (such as Innerfidelity). Regardless, I can assure you that the FR response graph is both honest and accurate. Not to mention looks nice and is easy to read. 
 
    The frequency response curve of the M4U 1 is actually common in premium top-tiered headphones from manufacturers such as Sennheiser, HiFiMAN, and Denon. Slightly enhanced bass, linear mids, and treble with a gentle roll-off is what many audiophiles consider to be the proper FR curve; It is not surprising that manufacturers would choose to tune their drivers this way. While I personally have not heard any top-tiered planar magnet headphones, I have heard some of the the best of the best when it comes to the dynamic transducer variety; The quality of the M4U 1’s driver holds their own against it’s more established competitors. However as good as numbers and charts are in determining a baseline reference, real world performance is where it counts. This holds especially true for the M4U 1 as the Room Feel Technology adds noticeable effect that helps distinguish itself from the competition.
 
 
Tonal Qualities
 
    Music is quantified by more than just the bass, midrange, and treble and therefore I am not going to spend too much time going over the tonal qualities in great detail.  My reasoning behind this decision is that overall, the M4U 1 handles the whole frequency spectrum exceptionally well with no perceived negatives or shortcomings, and I would rather put forth the time and effort into covering the many other aspects of the sound.
 
Bass: The M4U 1 has some of the most accurate, detailed, and fast bass I have head in a dynamic transducer. There is absolutely zero sub-bass bloat nor bloom, and absolutely zero bleed into the lower midrange. When called upon the M4U 1 delivers mid-bass punch as well as sub-bass rumble that is accurate in quantity yet gives gives a good sense of power and energy without being over-bearing. Room Feel Technology not just works, it works very well; It is as if the bass is a separate entity that cleanly and seamlessly compliments the rest of the frequency spectrum. Whether it is the low registers of a double bass, or the fast electronic beats of todays modern music, the M4U 1 has no problems accurately handling the low frequencies in any genre. 
 
Midrange: One word; Smooth! Despite being relatively linear, the midrange has an engaging sound. Instruments are rendered with great precision. A slight bump at the lower end adds body to male and female vocals, which are accurate with no hint of grain or veil. Dialogue is clean, clear, and precise. Considering the midrange makes up the bulk of the sound, the M4U 1 handles the diversity uncoloured and with ease.
 
Treble: Like a perfectly fermented champagne with just the right amount of sweetness, the M4U 1’s treble is crisp and clean with a touch of sparkle and shine. Fast and detailed with accurate decay, the treble is non-fatiguing. Sibilance sounds natural with no accentuation or harshness. There is no perception of artificially boosted or unnatural detail. With a gentle roll-off, he treble is what it is, sweet; Great extension, non-peaky, zero distortion.
 
 
Headstage
 
    Perhaps one of the more prominent aspects of the M4U 1 is it’s soundstage. Simply put it’s huge, and not just for a closed design either. The overall soundstage is not as airy as an open back design, none the less the M4U 1 either rivals or surpass headphones of that nature. A good analogy would be that the M4U 1 sounds like the music is being rendered in a large room, whereas a good open back headphone sound like the same large room but with the windows open.  Another interesting quality of the sound stage is that despite having drivers that are aligned flush with the head, the overall directionality of the sound is more indicative of two angled loudspeakers rather that of a general left/right circular radius commonly found in a closed circumaural design. This provides exceptional forward depth that is both wide and tall. Overall the stereo transition is not only natural but seamless; The M4U 1 do not have a left/right/centre ‘3-blob’ soundstage, nor do they have an obvious centre break exposing the left/right divide. Instrument and vocal placement is precise, accurate, and natural. 
 
 
Amping and Scaling
 
    The M4U 1 are rated at a standard 32 Ohm with a sensitivity of 102 dB, meaning one should have no problem achieving good sound out of virtually any device that has a 3.5 mm phono jack. While the M4U 1 certainly could benefit from a more powerful amplifier, I was surprised how universally good they sounded coming out of devices such as an iPod, HDTV headphone jack, Micro Gameboy Advanced, or a PC’s onboard audio. Equally surprising was how easily the M4U 1 took to both EQ tweaking and bass-boosting circuitry, showing little distortion and scaling nicely to the adjustment. Overall, it was difficult for me to find a source where the M4U 1 sounded weak, underpowered, or unrevealing; A true testament to their engineering.
 
 
Versatility
 
    How many times have you read that ‘ X ‘ headphones are great with Rock and Country music but fall flat when it comes to Hip-hop or Dance. Or perhaps that ‘ X ‘ headphone sounds marvellous with uncompressed Classical or Jazz yet don’t do modern music justice? Sometimes ’ X ‘ headphones sound very musical but may not be ideal for a competitive gaming session. When it comes to overall versatility, the M4U 1 may as well be nicknamed “The Jack of all Trades” as it handles all forms of sound reproduction with absolute precision, speed, and clarity; There is not one single specific type or genre that these headphones cannot handle, period. This can be attributed to the actual science behind Room Feel Technology, and helps reinforce Paul Barton’s claim that headphone manufacturers need to realize it’s importance and incorporate the ‘room’ into their sonic design.
 
    Whether it be a highly compressed lossy track or a lossless hi-res DTS soundtrack the M4U 1 simply refused to ultra-highlight any ugliness of the sound. Unlike other headphones where the more detailed and resolving they are the worse poorly mastered tracks sound, the M4U 1 holds it’s composure. Although I am not going to deny the fact that you will hear flaws and imperfections in certain recordings, I will say that the M4U 1 handles these issues with grace. Loud / low DR scale lossy tracks commonly found in virtually all modern music are very tolerable, while 24-bit / 96 KHz+  lossless tracks sound simply stunning. It is as if the M4U 1 shows compassion for the poorly mastered while allowing fine detail to shine with recordings of higher quality, all while being 100% passive. My hat goes off to the great engineers who helped design the M4U 1 as I can now revisit my music library and not worry about what is coming up next on the playlist.
 
 
The Sound - Review
 
Mac OS X 10.10.2
Audirvana 2.0.6 
AIFF lossless source files
TosLink (optical)—> Teac UD-H01—>  Ultralink  3.5mm interconnect—>  M4U 1
 
Midrange Purity
Angel of Harlem - The Persuasions
Three For All - The Bucky Pizzarelli Trio
Bring it On Home - C.C. Colletti
 
    Midrange purity is perhaps one of the most important qualities necessary for sound reproduction. The body of the sound (voices or instruments) comes solely from this frequency range. So often voices, despite sounding clean and accurate, sound detached from the ‘physical body’. While this can be contributed to the recording itself, the hardware plays an equal role in the presentation.  ‘Angel of Harlem’  by the a cappella group The Persuasions is a good example of vocal midrange purity, and the M4U 1 beautifully creates an excellent awareness of body. Each voice of the five members had a good sense of chest, sounding like it was resonating from within the diaphragm rather than that of five floating heads. Detailed and full of life, from the deep baritone lows to the silky smooth highs, the tonal qualities of each members voice were as uniquely distinct as they were visceral. It truly sounded like there were five men singing in front of three microphones.
 
    Instruments can too suffer from a lack of body, especially with today’s preference of over-processing and the quashing of the dynamic range in recordings. Thankfully ‘Three For All’ as performed by The Bucky Pizzarelli Trio does not suffer from the latter. This jazz trio, consisting of three guitars, is a good selection to best illustrate the sense of a physical body in an instrument’s sound. With unadulterated transparency, every pick, every strum resonated within the shell giving way to a full bodied experience of sound accuracy. It was as if each note was it’s own entity occupying it’s own space within the guitar, being both well defined and tactile in nature while maintaining cohesion to the sound. While this piece was purely instrumental, the performer’s energy was apparent through both their playing and their humming along to the rhythm. 
 
    Recorded at Chesky Labs with the latest in Binaural+ Technology, the Led Zeppelin cover ’Bring it On Home’  as performed by C.C. Colletti is a good test of midrange purity in a natural environment. I decided on this song because it was the sole track on the album that has a male voice accompanying Caroline’s, and because he is occupying the same space as his guitar the vocals can get garbled in to the strumming and sound grainy. Providing excellent body with perfectly rendered timbre, the M4U 1 handled this trouble with ease, cleanly separating the two sounds giving both the singer and instrument their own space while still maintaining their relative position to one another. Of course, the songs highlight is that of  C.C.’s sweet Southern voice. Full of energy, her vocals sang out with complete transparency; The textured raspiness of her voice was smooth with not even a hint of grain, reaching the top octaves with perfect clarity. Every strum of the guitar yielded the individual reverberation of each string, while the harmonica belt out it’s notes with an echoing sense of soul. Modestly sitting off to the far right, a weighted feel of power emanated with every pluck of the upright bass, filling the studio with a deep lucid sound.
 
 
Bass Resonance
Bass Resonance- Best of Chesky Jazz and More Audiophile Tests, Vol. 2
Ain’t No Sunshine - Christy Baron
Up On You - Coming Soon
    
    When pushed, a headphone’s driver can produce unwanted and nonmusical sounds. This what is commonly referred to as distortion and the sound produced can not only lose it’s overall detail and resolve, it can cause bloat and bleed into the the lower midrange. It is far too common for headphone manufacturers to artificially boost the lower frequencies to compensate for their tendency to distort. This may be appealing for both modern recorded music as well as the younger generation’s preference for BIG-BASS, it is hardly ideal for listeners who want quality over quantity. The M4U 1 not only have the speed, the power, and the accuracy, they have the energy with the ability to reach DEEP when called for; Response is solid down to 26Hz with a gentle roll off down past 20Hz.
 
    The tracks I chose for this section are a good test of both natural as well as artificial (or synthesized) bass resonance. First, ‘Bass Resonance- Best of Chesky Jazz and More Audiophile Tests, Vol. 2’  features a solo stand-up bass approximately 3’ from the mic located in a large studio. Every note featured a sharp transient pluck followed by the deep resonance of the body. There was a human quality to every pluck with real sense of flesh pulling on the strings which twanged and reverberated along the frets. Never was the response boomy or bloated, just a pure, clean sound with power and energy felt with every note. 
 
    Moving along to ‘Ain’t No Sunshine’, again featuring a solo upright bass but this time accompanied by Christy Baron. This is a good test at showing the power and control of the bass when challenged with maintaining transparency to the midrange. Once again the M4U 1 masterfully handled the bass with precision and control with absolutely no bloat nor bleed. Every note resonated with each pluck showing both energy and grace. Christy’s sweetly seductive vocals were rendered with such subtlety and clarity, giving a good sense of breath yet the M4U 1 refused to lose control of the lower bass, never overpowering or shadowing her voice.
 
    This section would not be complete without a true test of extreme bass. For this I chose the trance/electronica track ‘Up On You’  from the Audiophile compilation by Audiomatic. As one would expect from this genre, this track features impressive amounts of elevated mid-bass and sub-bass. The M4U 1 was able to deliver mid-bass punch with authority, yet still revealing the nuanced low frequency textures of the electronica sounds. Sub-bass possessed impressive amount of weight and energy and was rendered with such speed there was simply no time to bleed into the higher frequencies. Simply put, the M4U 1 is more than capable of supplying ample but appropriate bass when needed, but nothing more. Bass-heads will be more than satisfied with the output quantity while audiophiles will pleased with the quality; Both will impressed with the absolute control.
 
 
High Resolution
Spanish Harlem - Rebecca Pidgeon
Allan Taylor - Colour to the Moon
Hajji Baba - Monty Alexander
 
    The audiophile classics I chose are a good test of the M4U 1’s ability to render fine detail and it’s overall resolve. Featured on several female vocal reference compilations, masterfully recorded in Binaural stereo, ‘Spanish Harlem’  by Rebecca Pidgeon contains high resolution detail that can be easily lost if the driver is unable to adequately perform; Not so here. Rebecca’s voice sounds very natural and just breathes with a good sense of space all around her. Every subtle in-between breath she takes can be easily discerned, and never did the sweetness of her vocals sound peaky nor possess any grain. The bass sounds full, robust, and detailed, never getting in the way or sounding overpowering. The strings are airy and sweet  yet don’t sound detached from the rest of the band. The shakers are located in the back of the soundstage but don’t sound distant, with each shake being unique and distinct. Nothing sounded congested or out of place, all while maintaining excellent transparency.
 
    ‘Colour to the Moon’  by Allan Taylor is one of B&W Audiophile Recording’s favourite reference tracks, as is mine. Alan’s voice is beautifully rendered with detail and emotion; Trenched with warmth it’s deep sound saturates the sound-space. Filled with both joy and sorrow, the delicate picking of the acoustic guitars render great resolve; Every strum glistened with texture, almost visceral, with detail so precise that I could feel the edge catching the coil of the strings as the pick glided across the surface. Possessing an almost holographic quality, the bass cleanly resonated from the back with deep, enveloping, and powerful detail, yet never sounding overwhelming to the contingent of sounds. Distant but never shadowed, the seductive sound of the saxophone gently echoed it’s tune from a far. 
 
    Equally impressive is how the M4U 1 render the finer details in Monty Alexander’s ‘Hajji Baba’. The percussive strikes of Monty’s piano were as dynamic as they were subtle;  Every note, every chord was distinct, full of energy while maintaining transparency and clarity. Besides Monty’s dynamic piano work, this track features percussion with a dazzling array of cymbals, and is why I chose this piece in particular. Each explosive strike of brass resonated with excellent attack and release resulting a a multi-layer of textured and shimmering sound with a touch of sparkle. Never did the cymbals sound thin, brittle, or weak yet possessed an almost ethereal delicacy. The beat of the drum, though not as forward as the rest of the kit, had both body and impact. The upright bass sat politely behind the rest of the music, each pluck robust, weighted, and detailed yet remained modest.
 
 
Transparency and Focus
SlÂttar p tunga - Springar Etter Gudmund Eide - Berit Opheim Versto
Haydn: String Quartet in D major, Op. 76, No. 5 - Finale - Presto - EngegÂrdkvartetten
Wa Wa Wa - Candido Camero
 
    Transparency can be defined as sound that is clear and uninhibited, while focus refers to the definition or ‘clarity of outline’ of that sound. Without these qualities, instruments and vocals can sound cluttered with the notes sounding fuzed together thus taking away the natural detail and convincing resolve. ‘SlÂttar p tunga - Springar Etter Gudmund Eide’  is a trio of female yodellers and best illustrates the transparency and focus of the human voice. The rapidly fluctuations of the falsetto were rendered with absolute clarity, speed, and precision. The characteristics of each singer’s voice were trenchant in their execution; Vocals were full bodied and had a feel of naturalness, each breath having a sweet innocence. Well defined and coherent, there was no muddled notes, no grain, no harshness, just an open window to the sound.
 
    ‘Haydn: String Quartet in D major, Op. 76, No. 5 - Finale - Presto’  as performed by popular string quartet EngegÂrdkvartetten. While four stringed instruments may sound simplistic by definition, the complexity of their sound is not; This piece boasts very fast and dynamic bow and finger work by the performers. Each performer’s instrument exists in their own transparent space with their relative positions apparent to the listener. The sharp transients are perfectly complimented with the airy, dry yet sweet sound of the reasoned bow; Fast and detailed, well textured and defined, every note exhibited both energy and life. Both transparent and focused, the characteristics of each instrument was easily discernible, highlighting the M4U 1’s overall precision and resolve.
 
    Finishing off this section, Candido Camero’s ‘Wa Wa Wa’  is a fun Binaural recording. Set in a large soundstage, mixed with dynamic sound of brass horns, this track features a plethora of funky percussion and voice work. With a good sense of impact, each strike of the hand against the skin resonated from within the drum’s chamber, sounding detailed and discrete with a focused outline of it’s shape; I got a good sense of not only the position of each drum within the sound-space, but the position of the performers hand or mallet upon the instrument. Cymbals explode with a textured shimmering sparkle. Distant yet easily discernible and well rendered, the vocals relayed the performer’s vigour giving way to a sense of natural energy. The crisp, bright sound of the brass are focused, possessing good bite that excites the senses while maintaining excellent transparency. Though subtle, the guitar sits gently behind the percussion but is not overshadowed with each pic presented with great detail and resolve. Nothing sounded cultured, just pure musical glue.
 
 
Depth 
Dr. Chesky's Sensational, Fantastic, and Simply Amazing Binaural Sound Show
Dr. Chesky’s The Ultimate Headphone Demonstration Disc
 
    There is no better studio that better understands natural depth than Chesky Labs, and I can think of no better compilation of test tracks that would be more fitting. In all honesty, I did have my reservations at first by choosing to go with Binaural recordings. As good as they are at creating a more realistic sense of space and natural depth, more times than not I found Binaural recordings to be lacking in absolute precision. This is not the fault of Binaural technology, rather the inability of the headphones. Manufacturers unfortunately try every trick in the book to artificially create depth with the end result being a more expansive soundstage but one that sounds distorted or unnatural. For example the Height Centre Bell : Test track would indeed give an excellent sense of a rising sound, however that same height test on either the left or right channel were not straight; The sound would be skewed and follow the shape of the headphones cup as opposed to a straight rise. With open backed headphones, left/right height can be presented with more of a recessive step-out (or what I like to call sound floating away) rather than a convex curve. 
 
    The M4U 1 are a good example of Binaural technology sounding right. Whether it be the height tests, the walk-arounds, or the surround voices, each position of the sound was not only precise but natural. There were no skewed lines, each voice seemed to emanate from where they were announced, and never did elliptical walk-arounds sound flat instead perfectly followed the instrument’s path. There was an realistic sense of natural depth with each announcement of distance from the microphone. Whether it was 3’ or 30’, I believed the instrument or voice I heard were in fact recorded at that distance. It was surreal, almost haunting when Dr. Chesky announced he was about 30’ from the mic on the right side and started walking closer and closer, announcing his movements until he stops right before my and whispers into my ear “ Only Binaural technology can do this… “ ;  Not only was it convincing that he was walking towards me in a large cathedral, I could literally feel his breath upon my ear. Perhaps one of the most impressive examples of natural depth was when Dr. Chesky gave me a virtual shave. The movements and precision of the sound were so believable it made my ears twitch in reflex thinking a razor was about to clip them.
 
 
Rhythm and Pace (PRaT)
This Song is For You - Johnny Frigo
Sweet Georgia Brown - Montey Alexandar
Para Los Rumberos - Santana
 
    Rhythm and pace, otherwise know as PRaT, by definition is quite ambiguous and is often overlooked. This term gets thrown around a lot, and often incorrectly used. Essentially, rhythm and pace relates to the overall energy of the track. It demands a physical response to the music and should make the listener want to bob their head, tap along with their foot, or get up and dance. Since PRaT can only be quantified as a whole, I won’t be breaking down each song individually as they are only listed for reference; The tracks I chose offer up the potential to make the listener get up and move. Thanks to Room Feel Technology the M4U 1 dominates in it’s ability to relay the energy of the music. Whether it’s the fast latin rock of Santana’s ‘Para Los Rumberos’,  Johnny Frigo’s dynamic jazz trio playing ‘This Song is For You’, or the visceral sound of two bands facing off in Montey Alexander’s ‘Sweet Georgia Brown’,  the M4U 1 makes short work of all of these tracks. Lively and natural, tactile and detailed, resolved with speed and accuracy, I got an excellent feel of the performers energy being relayed through the transducers that was as palpable as it was visceral. Before long I found myself tapping along to the rhythm with my fingers upon the keyboard. Of course there is a common tendency of the listener to turn the volume dial to 11 when rocking out to rhythm and pace, and the M4U 1 says to this an enthusiastic ‘Yes please!’. At higher volume the sound remained undistorted, allowing me to feel the full impact of the energy while the frequency response remained true to it’s form.
 
 
Last Thoughts
 
    In all honesty, I could have transplanted any song from one category to another. The M4U 1 made short work of any track I chose. Detailed, textured, clean, transparent, natural and pure, it is difficult for me to find anything negative to say about their overall sound. Do the M4U 1 sound perfect? To my ears they do. Is there any aspects of the sound that could use refinement? Absolutely. Not because I feel there is anything lacking, rather I believe that nothing is ever technically perfect, especially technology; There is always room for improvement to be had with anything and everything. In fact a little birdie told me that PSB is working on a new flagship headphone. Ok, it was Paul Barton himself hinting at Head-fi’s Jude when asked what he is working on next. Needless to say I look forward to seeing what PSB does next. 
 
“ Hey Paul, if you are reading this I just want you to know that it would be awesome if I can get a sample pair for review purposes when that day arrives eh! “ 
 
 
Closing Comments
 
    First and foremost I would like to thank you good folk for taking the time to read my review of the PSB M4U 1. If you didn’t think it was a good read, I hope at the very least you found it to be informative. In writing this review I gained a new found respect for people who have written many themselves; It was quite daunting trying to decide what to write, let alone the format. My initial intent was to write a quick praise for my new favourite headphone, but the more I wrote the more I felt the need to write more and before long I found myself angling lights and setting up my tripod. It is quite obvious that I love the PSB M4U 1, and I felt it was difficult for me to stay objective. In all honesty, all I wanted to type in giant bold text under each section was ‘ Wow these are good! ’ over and over again. Considering that I live in a Capitol city with one of the highest ratios of retailopulation, it speaks volumes (pun intended) that it was difficult for me to find a store that had the M4U 1 in stock. In my opinion, the M4U 1 are a true sleeper hit. 
 
    I tried to think of a good closing cliché that would best describe the M4U 1, but in the end all I could think of is that PSB and Room Feel Technology really hit a home run first time up to bat. They hit the ball so far out of the park it crashed through Zeus’s patio window and disrupted the game of back yard croquette he was enjoying with Jesus. You don’t have to go looking too far to find the many accolades the M4U 1 has received since their release in 2013. From making the list in Head-fi’s Buyers Guide, to The Wire Cutter having the M4U 1 as their top pick for two consecutive years, PSB’s first foray into headphones has accomplished what it’s competition has yet to even attempt; A sonic signature that takes into consideration the listening environment in which the music was intended to be heard. The end result of this forward thinking is one of faithful and accurate sound reproduction that holds true to the original recording. While there may be headphones who’s sound may be more refined or resolving, it’s not by much and nowhere near the price point of the M4U 1. Room Feel Technology is very real and is as much of a game changer as Paul Barton’s 1974 loudspeaker research was 40 years ago. It is time for the old guard to wake up and embrace a new standard in headphones.  Le Roi est mort, vive le Roi! 

Setup:
 
System #1:
Macbook Pro Retina, Fidelia Software, Fiio e17 Alpen
 
System #2:
Mac Pro, Fidelia Software, Headphone Out or Fiio e17/E09K combo
 
Some of the tracks used to test:
Clean Bandit - Cologne
Clean Bandit - Come Over
Alicia Keys - Diary
Ed Sheeran - I See Fire
Ed Sheeran - Thinking Out Loud
Imagine Dragons - Polaroid
Imagine Dragons - Friction
Tedeshi Trucks Band - Midnight in Harlem
Tedeshi Trucks Band - Learn How to Love
John Mayer - In Your Atmosphere (Where the Light Is)
Nickel Creek - Out of the Woods
Nickel Creek - This Side
The Beatles - Come Together
Phantogram - Black Out Days
Van Morrison - Crazy Love
Van Morrison - Caravan
 
Packing:
 
I found the packaging/presentation to be nice with the headphones.  The included portable case is decent, and provides space to drop in your iPod/DAP.  It included two cables, one with a mic and one without.  While it was nice to have both options, the cables feel thin and cheap to me, and I am concerned about their longevity.  Otherwise, things were fine. They also come with extra ear cushions, which is a nice plus.
 
Build Quality:
 
The first thing I thought seeing them in person: These look a bit like "fashion" headphones (e.g. Beats), I hope they don't sound like them. The headphones fold up for portability.  Unfolding them the first time was a bit disconcerting, as there seemed to be a lot of flexing of the plastic before they clicked into their open position.  I was a little scared of breaking them.  Having now folded and unfolded several times, it's gotten better.  When pulling the headphones apart to fit around my head, i noticed the edges of the pad on the headband separate from the plastic. I don't know if this is design or what, just looks odd. Also, the plastic looks as though it wouldn't take much to crack, I hope it doesn't. The super shiny plastic collects fingerprints like crazy.
 
Ear pads seem good, and overall assembly looks nice.  I didn't notice any glaring assembly inconsistencies, etc.  
 
Fit:
 
This frankly is the #1 big downside to these headphones, and it's a big one.  So, so frustrated on this point.  I have a fairly average size adult male head.  I have worn many on ear and over ear headphones.  The most uncomfortable out of the gate were Grado SR125s, because the ear pads would make my ears hurt after a while.  These PSBs are just plain painful.  The clamping force on my head is just too much.  It actually distracts from listening experience within the first 15-20 minutes, and I just have to remove them after 30-40 min of use.  Also, the pads are a bit shallow.  I can feel my ears touching the face of the drivers, and the insides edges of the pads. They also get hot, but that doesn't bother me too much. Compared to the clamping, these other items are no big deal, and wouldn't discourage me from keeping them. 
 
Additionally, these do look a bit goofy to wear.  Fortunately, I don't care what headphones look like as long as they fit well and sound great.
 
Sound:
 
Let me first say that generally for listening, I like open over ear headphones.  I really only started looking at these as a means to enjoy music and not annoy my wife in the same room.
 
Most closed cans I've ever used have problems with muddy/messy bass.  These were quite a surprise.  They are both clear and sparkly at the high end, have clean full bass at the bottom, and detail through the whole range.  I wouldn't say they are "bass head" heavy, but a nice full bass presence.  Additionally, these headphones can handle complex or busy audio while maintaining clarity and detail.  As a matter of fact, there is enough detail and clarity that I noticed problems in a few FLAC tracks, so I will be re-doing them.
 
They have a warm (thick in the 300-500hz range) tone.  For my preference, I found that if I eq that range down ever so slightly, the overall sound is perfect for me.
 

 
 
I found that these cans sound a little better being driven from my Fiio E17 than from a headphone out alone.  While these are efficient, that little extra power just helps them open up.  However, I found that driving through my E09k desktop amp was basically pointless (no improvement over the E17).  So, while they benefit from a little more amplification than a straight headphone out from a computer or portable device, there doesn't seem much benefit in giving them lots of power.
 
The only negative I found is that sometimes at louder volumes these can tend to lose their composure, and can become fatiguing in the high frequencies. I found this in all amplification scenarios.  I don't usually listen super loud, but sometimes I am in the mood to rock out a bit more, and noticed these can get uncomfortable with certain songs.
 
Conclusion:
 
It's simple really.  I love the sound, and I hate the fit.  So frustrating.   I have been seriously debating returning them.  Each time I put them on for a listening session, I pray the clamping force would be less, but so far, no such luck. 
 
 
*** I have been wearing them while writing this review, and it's a good thing I am done typing, because my head and ears are starting to hurt.  I just need to finish enjoying this song so I can get relief ***

These are fine-sounding cans, very detailed and clear throughout the frequency spectrum. I found them to be quite revealing - I heard details that were missing in my Shure IEMs that cost over twice as much. They're also exquisitely balanced; nothing sounds over-emphasized or artificial. In terms of overall sound quality, accuracy and general "is this a pleasant listening experience?" feel, these are an incredible bargain, and completely justified in the rave reviews they receive here and elsewhere. I couldn't find any genre of music that reproduced poorly with these, though I do not listen to much classical. Rock, jazz and electronica all sounded excellent.
 
My primary complaint is one of comfort, and I should make it clear that I have a huge head that is prone to getting hot easily. The PSBs caused physical discomfort for me quickly, to the point that I had to return them. They strongly clamped my oversized noggin, and the leatherette pads caused sweating. I simply couldn't wear them for very long without discomfort.
 
It's also worth noting that these headphones are almost comically large, to the point that my wife burst out laughing the first time she saw them on my head. These are definitely "in-home" cans - they're big, heavy and look every bit like you're lugging a couple sizable speakers around on your head. There are no compromises made here in service of compactness or weight - these are monstrous.
 
Build quality was good, but some of the seams and molds seemed a little rough, and the unit I got came with one bad cable (two are included, one with and one without an inline mic/remote). But I can't really fault a small specialty audio manufacturer for not having Apple-level assembly quality, especially at this price. Ultimately, the sound is amazing, and you're not looking at the thing while you're listening anyway. I don't know whether build quality is a problem for reliability over the long term, as I returned them.
 
These are a true bargain if you can wear them comfortably.
 
Testing was done with the Audioquest Dragonfly 1.2, mostly lossless files, a few hi-res files, and a considerable amount of ear sweat.

I could not recommend these headphones more, they sound better than anything else i have had the opportunity to listen to for more than five minutes. They take the best parts of the headphones i owned previously and puts them all in one package and refines them even more. More controlled lows than the m50, better highs than the ad700's and keeps their sound stage, and the mids of the MS1 with more detail. Just an incredible headphone.
 
Buy these now.

ALSO: I bought my pair from videopro in Australia, and they arrived the next day with free shipping. There was very minor damage to one corner of the beautiful packaging but for the most part I am a very, very happy customer.

I needed a closed pair of headphones to use during late-night listening sessions, when my wife and daughter are asleep, and where my (VERY) open-backed Grado PS500's leaked too much sound. The Grado's are amazing, and had they made a closed headphone, they could simply sign me up. So I began a journey to find the ideal audiophile closed headphone, which would also isolate noise effectively in a passive way, and ideally be portable. I tried the Beyerdynamic DT1350, great treble, punchy bass, and good mids. It just wasn't as "FUN" as I was looking for. Additionally, it got uncomfortable being supra-aural on sitting on the ear. I also tried the VModa M100, as I had read it was more accurate than their previous offerings. Ok, it is incredibly built, military grade even. But it was just still too colored for me, adding bass in places that didn't need it, and overpowering the mids. The treble was fairly good, but a little rolled off at the limits. Next I tried the Sennheiser Amperior. This is a good headphone, and many will like it. I thought the highs were a bit zazzy and hot, especially with "S" and "T" sounds. Of course, the source was critical, and the better the quality of the file, the better the output. I just couldn't put my finger on why I didn't want to keep them, but the clamping force was the deciding factor. Throughout this search of trial and error, I came across several glowing reviews for the PSB M4U 2's, which featured active noise cancelling. I had never been a huge fan of the way added electronics altered the sound quality and transparency of these types of headphones, but many respected audio publications said they were different. Then I read that PSB had recently released a new model without the active noise cancelling. It was difficult to find a review for this pair specifically, but I decided to pull the trigger. WOW. This is the first headphone that Paul Barton of PSB has introduced, and they knocked it out of the park. These are really phenomenal sounding headphones.

Treble: These have as close to a perfect, extended treble for their price that I could possibly imagine. They have excellent resolution and detail, easily keeping up with phones 2-3x their price. They have an extremely balanced top-end that has sparkle, energy and impact, rendering all range of instruments, both electric and strings/percussion with lifelike precision. They never fatigue me and have little to no sibilants. Being a drummer, the realistic snap of snares is a special treat.

Mids: Fantastic, slightly forward, with just the right amount of presence and weight to immerse you in the music. Great with both male and female vocals, and well rounded with all genres, from Rock to Hip-Hop, EDM to Classical. Truly, it is hard to find faults with the frequency range and presentation that Paul Barton and team engineered into these beauties.

Bass: Awesome. Awesome. Awesome. Punchy, able to achieve sub-bass, and so accurate and fast. They do their best to add nothing to the original intended sound, but they can really slam when the song calls for it. I've played them pretty darn loud with my Nuforce Icon HDP, and I cannot get them to break-up.

I'm just in awe that these are only $299. Audiophile steal. Period. Please don't feel trepidation to make the purchase due to the low amount of positive reviews online. Folks who have heard the M4U 1 and the M4U2, and compared them back to back, have preferred the transparency and naturalness of the M4U1. You're not getting less headphone if you don't care about the active noise cancelling. They myriad of reviews are correct. Buy these, you won't be disappointed.

Happy Listening!

Overview
 
I listen to all types of music: from mixtapes of dubious quality from DatPiff to FLAC rips of half the MFSL library. I'm generally listening at my desk, though I also listen walking the dogs, walking myself, on the subway, lying in bed. About 65% of the music I listen to is rap, 10% electronic, 25% rock/pop of some sort. I'm a music critic, and my usual tools for evaluation are the Audioengine A5 speakers, Denon AHD2000, Shure SE215, Apple iPhone earbuds, and now these, the PSB M4U1. Honestly, I just listen to a lot of music with whatever's best at hand.
 
The PSB M4U1 are some of the best headphones I've personally heard, and compare favorably (to my recollection) to the HD650 and IE8.
 
SOUND
 
I've found the headphones to be very precise and revealing. They don't necessarily present a wide soundstage, but the separation is very good. Different elements of a track, or different instruments, all receive pretty clear characterization. I've actually noticed a lot of different ambient sounds in studio recordings since using these.
 
The treble isn't at all rolled off, so they seem a little 'sharp', but I suspect that's because I'm used to slightly muddier or bass-heavy earbuds like the IE8 and SE215.
 
As for the bass - it's good. It's certainly not 'powerful' or overwhelming, but it seems accurately accounted for. When you've got the volume up, there's a somewhat physical bass 'hit' (sub-bass, I guess some people might call it?). I don't mind super-duper overwhelming bass; I turned the bass setting on my IE8 all the way up, and sometimes wanted more. I find the PSB M4U1 more than sufficient. They don't bowl you over, but the total sound package is such that the bass doesn't need to overwhelm to have a solid presence. As you can see from the length of these paragraphs, bass is pretty much the second- or third-most important thing for me, and these have it.
 
The PSB M4U1 have revealed some flaws in my music that I have previously missed. That's sort of a plus and a minus. Since I bought them to be an 'every day' sort of headphone, I'd like them to 'enhance' my experience. But if the source material (all FLAC, 320, or V0) is flawed, well, it's not their fault. Still, I didn't notice this sort of resolution with the HD650 or AHD2000. That could either be a plus or a minus.
 
Along the same lines, I think it could be that I wasn't (somehow) driving the HD650 sufficiently. I've had no such problems with the M4U1. They seem to drive easily, though, and I may sound like an idiot here, I haven't amped them. Maybe they sound even better amped. Compared to the un-amped AHD2000, they sound much better: clearer, better separation of sounds, more accurate bass.
 
Fit and Finish
 
OK, this is where the PSB M4U1 lose half a star. I do have a pretty big head. I wear something like a 7 3/4 hat. My ears might be a little big. Whatever. The tips of my ears hurt after wearing the headphones for more than an hour. Given how great they sound, this sucks. I never want to take them off, but I've found after a week that I have to take frequent breaks or suffer sore ears. The headphones also look pretty ugly overall, and they look stupid on my big head. (But hey, if you have a pinhead, maybe they'll look cool on you.)
 
I got the gray pair. They look like a really bad knock-off of the HD650: they're all plastic, no metal, and just a plain, upside down U shape like wearing a cross section of a bucket on top of your head.
 
EDIT: I just remembered another slight cavil. The cable with the mic/remote is very long. Since the cable is inherently for portable use, I wish it weren't like three feet long. Also, the mic/remote is really just a play/pause button; there's no volume adjustment on it. I still wouldn't knock the M4U1 down to 4 stars over this, but it's close. The sound is the most important thing, but obviously the headphones must be used as objects in the world, and I find their use to be highly problematic.
 
Conclusion
 
Given that these headphones hurt both my body and my pride to wear, the fact that I'd still rate them a 4.5 should give you an idea of how great they sound. They sound great. That's the greatest attribute for a headphone. I don't care if I look like a dork and have sore ears. It's worth it.
 
BUT - If you're on the fence from a sound perspective between these and, say, the Sennheiser Momentums or something, I'd say pick the other ones. I find these uncomfortable, ugly, and a chore to use. They do sound good, though.

TLR - these freaking ROCK HARD. Buy them. Now. Seriously, why are you still reading this? GO GO GO GO GO GO GO GO GO GO!!!!!

A review on the PSB M4U1:

First let me say that I enjoy good music. I don't care what genre it's in, I just want good music. You're probably asking "How do I judge whether or not music is good?" Very simple: music should tell a story. I don't care if there are words, it doesn't even matter if you hear one story and I hear a different one. It's the story that counts. Otherwise what is music but some random noise? You may ask next "Well what makes you the authority on whether or not there is a story? Wouldn't the artist know better?" I should hope that the artist would know. I'm definitely not the be-all, end-all authority on good music. I don't claim to be. I'm just someone who knows a lot about music and has strong opinions. I'll share them if you want, otherwise just find your favourite CD/MP3/FLAC/ALAC album and enjoy. Liking good music comes with a bit of an issue - a good soundsystem to play said music on, especially when portable/at work. Unfortunately most of the people I work with like very specific music so I don't have the option of bringing in a nice stereo system to work. That and bringing a stereo system on the GO Train or TTC (mass transit for non-Ontarians) when I take those also wouldn't work very well. Hence the need for a good pair of headphones. I like headphones over earphones or IEM as I find after a couple hours max an IEM system fatigues my ears and I get sore. Nothing better than a good IEM while riding my motorcycle but general day-to-day usage I'll take a good pair of headphones anyday.

My testing rigs are:

iPhone 4
Laptop direct to headphones
Same laptop coupled with Fiio E07K, connected with USB for proper DAC

Music samples included (artist only for ease of reading/typing):

Hans Zimmer
John Williams
Danny Elfman
DeadMau5
Girl Talk
Flyleaf
Nonpoint
Metallica
Five Finger Death Punch
In Flames
Lady Gaga
P!nk
Papa Roach
Seether
The Verve
Shinedown
Sevendust
Pop Evil
Elton John
Lady Antebellum

The Review:

Unboxing the PSB M4U1 is a study in craftsmanship and showmanship, without over-doing it. A nicely appointed clamshell style box covered with a single sleeve to keep everything together. Opening the clamshell presents the headphones in their hard travel case on one side, the cords, spare ear cups, instructions and warranty information in the other. Both sides of the shell have a cover over the accessories, making sure they are protected. Taking the travel case out of the clamshell and opening it up to see a beautiful piece of gadgetry. The headphones look like heavy beasts, no hiding it. Lots of other reviews have stated that the weight of the phones is probably their greatest downfall. My old cans, a set of Shure SRH440s, weighed almost as much (according to manufacturer's spec sheets) yet felt heavier by a wide margin. These headphones are not light for sure but I don't get the fatigue some people have mentioned. I found the distribution of weight was perfectly proportioned with the majority on the top of my head and very little on either ear.

Accessories include two cables, one with iPhone/Android control and a mic, and a second cable with nothing but the cable for direct signal to the phones from whatever device you're using. There is also a 3.5 to "normal" jack converter and a 3.5 to dual 3.5 converter (some airplanes require this kind of connection for stereo sound). The headphones also have a unique feature I did not see in any other vendor offer - the ability to plug the jack into either side of the headphone. If your device is on your left side, plug the jack into the left ear cup. Right side for right. Or if you like having a cord go across your body do it that way! The second jack also has an interesting feature - a second set of headphones can be plugged into the unused ear cup jack and the second pair of phones is driven in turn

The ear cups themselves feel...divine. There's no other word I can think of to describe them accurately. When I was shopping for new cans I tried out numerous vendor offerings, from Grado to Bose, AKG to Sennheiser, Audio-Technica to Sony, etc. For me the PSBs are the most comfortable ear cups I've ever felt. Made of some sort of pleather/abs combo that sounds ridiculous and uncomfortable yet is crazy comfy. Unlike memory foam ear cups or ones covered in velour, these don't make my ears sweat or feel squished. And yes, there are a number of headphones that have velour coverings on their ear cups.

Doing a direct comparison (either by switching phones and restarting songs or using the dual output of the E07K) showed that the sound issued by the PSB is a much cleaner, flat sound than other devices. As an example, the Audio-Technica was much punchier in the bass presentation, whereas the Shure's had a slightly crisper treble (to the point of almost pain...to much crispness isn't always a good thing!). I much prefer the flat, crisp sound issued by the PSB. I want to hear the music as presented by the artist and producer, not how the headphone maker thinks it should be played. The PSBs were also developed to produce a similar soundstage to what you would experience with a good speaker system in a normal room, instead of an audiophile lab like most companies. That simple difference is very clearly evident in the presentment of sounds.

If it wasn't evident before now I'm extremely impressed with these headphones. And you didn't read the TLR. Cost for these is a bit steep for some, not so much for others. I was able to get them brand new from a proper retail store for 279+tax, shipping included, making these the third most expensive soundsystem I've bought to date (Shure 535 and my full home theatre being the most). MSRP is 299+tax. Can you get headphones cheaper? Yup. Hell there are some good ones cheaper too - Audio-Technica M50, Shure 440/750/940 even, AKG 550 (although this one is only about $20 cheaper...). Will they sound as good? No. Not even close. At least not to me. What about spending a little more? At approx. $300 isn't there a gamut of "professional" sounding cans? Yes there is. Thankfully all the reviewers out there seem to agree with me - to get a better soundstage than the PSB M4U1s (or the M4U2 if you want noise cancelling) you'd need to spend anywhere from double to triple the price, or more.

Like most things in life this is definitely a YMMV thing as music is very subjective. Some people are bassheads, in which case they may not like these cans as they don't up the bass by themselves. They require some EQ fooling around for extra bass. Some others are trebleheads and it's the same issue - modifying an EQ settings is required for a more in-your-face treble punch. Even with that though I'd still recommend these to anyone. Why? Simple - every device that I know of has a built in EQ that you should be able to very quickly and easily modify, not all headphones give you the option to listen to the music as it is supposed to sound. Definitely try them out in a store first and for those with a S/HWMBO that may not understand spending that much on a pair of phones...to you I say it's always better to ask forgiveness than permission. Just make sure you keep the receipt.

Cheers,

M.