Pros: Really good slight warmish balanced sound. Comfort for a big heavy plastic headphone is actually quite good.
Cons: Massive size. The build is not very impressive. No real value in the NC and amp electronics, expensive for "old tech"
Let's start with the build since it is a hot topic on this headphone.
It´s not very confidence inspiring but it's chunky. Made out of mostly plastics and cast aluminum for the adjustment arms and probably aluminum or stainless for the hinges, this thing should be quite durable. However i don't see it lasting a lifetime. Since it's so heavy and the plastic seems to be of the hard kind that just cracks and shatter if dropped, i think that if this thing picks up speed during a drop, it's probably going to break. However, i don't usually drop my gear and i am a very careful person when it comes to my gadgets i personally don't see this as a problem, but it's worth knowing for some buyers.
Compare this to some much cheaper headphones from "headphone" companies like Beyerdynamic, AKG and some Sennheiser models or the undisputed heavyweight king of durability, the German Maestro 8.35-300 series headphones.The M4U is build "wrong" i would say.
Take note that this headphone isn´t new and it isn't (while sounding amazing) targeted at the pro-audio or headphone geek market. When the M4U2/1 saw the light there was an era of plastic fantastic cans with funky colors. If the M4U series was designed today, i bet it would look different.
The construction folds into a "portable" size. However when you unfold this thing of modern day "swag" the noise when the hinges goes into place, make you cringe. Not the kind of sound you want from a MSRP of 400 USD.
To summarize my rant here..It´s way to heavy for it´s own good. Instead of making out of durable plastics they added a lot of the shiny stuff to make it sturdier. I think it´s a shame.
It´s made out of a springy rubberish material. It´s not the worst but not the best. What is nice is that the plug is very small and sits flush with your device of choice. The microphone sounds rather good but it´s located to far down the cable. A mistake often seen on portable headphones. How hard can it be to make a proper cable? Either is it flat ( the worst thing ever! ) Or the microphone is way to low.
When the headphone is in active mode, you can press the little hump on the cable ( Where the microphone should be located btw ) This let´s the microphones for the noise canceling amplify outside sound to make it easier to hear without removing the headphones. Kinda of a nice feature.
Comfort? How does this massive contraption fit on your cranium? Well, surprisingly good.
It´s easy to find a good seal, the pads are of good quality and you get a replacement pair in the box, a nice touch! But nothing is perfect. Let me tell you what could be better.
The pads are to thin and to small. It's that simple. While the pads are soft and made of quality materials, when they get pressed around your ear they gets thin and your ear starts to touch the baffle. On my head ( and ears ) it's not really a big deal but i can absolutely see this an issue for people with larger ears or a larger head where the clamp get's the best out of these pads.
My favorite replacement earpads are the Brainwavz HM5. And they are too big, bummer! I have not found a replacement pad worth looking into since the main issue here is not quality, it´s depth.
Sound. Where it´s get interesting.
I did buy these cans without hearing them first, it's often how it goes down when i shop for cans. Part of that is the lack of demo units available around this part of the world ( Sweden ). Second, if there are cans available locally, the price is not nice! Heavy taxes etc yada yada makes this very expensive compared to the US for example.
Since i often buy cans like this, the first listen is something special. In this case i was pleased to say the least.
The sound out of this unimpressive thing made out of plastic is organic, vast and natural ( not neutral ) The headphone sounds damn good.
It´s a rather flat signature but with a warm tone that makes music and instruments sound pleasant and still with enough sparkle and detail to make it an interesting listen.
The bass is well weighted and goes deep enough but it can be a little honky and go up to the lower mid bass on some tracks. On the other hand this ads meat to guitar riffs and vocals. I would prefer more sub bass while still keeping the attack. Bass can be little lazy and honky but overall rather well tuned.
The treble is just enough. It´s organic and blends nicely in with the overall tone of the headphone. I would have enjoyed a better articulation in the treble though. A little bit more energy and crispness. However this is a dangerous area to enter when tuning a headphone. Specially something like this that has to be every headphone on planet earth at the same time. It´s enough treble, it sounds good. But it’s not magic.
Mid Range is well presented and not to forward. I think this is an important point to focus on. If mids are to forward people tend to not enjoy the overall signature ( speaking of the majority of the people here, not geeks like us ) Since the mid range blends a little bit with the bass it can sound a little hollow and honky. But hearing lyrics and detail from instruments like acoustic guitars are no problem here. It´s good and not tuned far back in the mix. It’s not magic, but absolutely good enough.
Soundstage is where it´s at with the M4U2. Really good surround feel and depth. Pinpointing instruments and details on a live jazz recording is a joy and really impressive for something “cool” looking like this. I’ve read that this headphone had good stage but i was not expecting it to be this good. Overall the presence blends together with the overall tuning and makes this a slightly warm and cosy experience. I think the soundstage is what makes this headphone stand out from the crowd.
Without soundstage and this organic flat-ish tuning the PSB M4U2 would be nothing. Nothing really stands out in the other areas of the sound signature. It´s the whole that is impressive. The bass is good enough, midrange and treble is also good enough, not fantastic. But when the “Room feel kicks in” you hear where it’s at.
Electronics..Yes! It´s powered by batteries and it’s why you should buy the M4U1 instead.
There is a built in amplifier which is great in theory but it’s to noisy. The headphone is easy to drive as is. It’s nice to have an easy to drive headphone that sounds this good.
There is also a active noise canceling funktion. This mode ads the noise of the amplifier plus the noise from the NC itself. However it does a rather good job with low frequency noise like engines, road noise etc. I can at least find a useful scenario to use this function compared to the amplifier. To bad you can't run the NC mode only without including that darn amplifier.
The active parts do NOT work on android phones..It makes me furious really. I know it’s apple only but it should not be. It’s a regular 4 pole plug on the cable, and the remote has one button only. Still when connected to any android unit ( nexus 6p, 5x etc ) all you get in active mode is static and ground issues. It´s all in the cable. A theory is that they somehow use the ground for the microphone on apple devices or the resistor or something like this to make it all work.
You can get it to work with a regular stereo source though. Xduoo X2, Sansa Clip for example.
To summarize this long review. The headphone sounds great but don’t pay for the active version, it´s not as good in drowning out noise as the Bose QC 25 and the amp is useless.
A great sounding headphone with a sound signature that appeals a lot of people. PSB tried to make this the only headphone you should buy, It got the “looks”, it “folds” it has “noise canceling” it even has a built in “amplifier” and that's what's wrong.
Lucky you who can get your paws on the passive version of this called the PSB M4U1 it´s a much better overall experience since it’s a headphone, not a space craft.
I bought this pair used for about 120 USD, money well spent! However the best price for a new pair is 350 USD ( passive version not available here ) and for 350, i think you should look for alternatives.