Pros: Great soundstage. Crisp, clean, even sounds across the board.
Cons: Needs an amp for best sound. Is that really a bad thing?
TL:DR - 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:
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):
Five Finger Death Punch
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 TL:DR. :) 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. :P