Pros: Excellent frequency response, very balanced sound. Excellent, punchy bass, energetic mids/treble. Great imaging, timbre & soundstage for closed cans.
Cons: Slightly heavy. Comfortable for up to 2-3 hours.
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.