I just received a pair of used Pro 900's, after being curious for the past ~3 years, from a fellow head-fier.
Back-story:
I remember reading every bit of info that I could about these... But I ended up buying the Pro 750's instead, because I jumped on a great deal for about $200 brand new. At the time, all the comparisons between the Pro 900 and Pro 750 indicated that they were very, very similar headphones.
I wanted a pair of headphones that were specifically suited for bass-heavy electronic music, and after receiving the Pro 750's I was a little bit disappointed. The bass presence and impact was better than my other headphones at the time (DT880's, AD700's and Alessandro MS1's), but not THAT much better. They definitely didn't match up to the descriptions of people with Pro 900's. They were decent headphones, and I used them for a while, but they always left me wanting.
Since then, I've acquired HE-400's, Q701's, a Matrix M-stage amp and a Matrix M-stage DAC (I had previously used a Xonar Essence STX soundcard). Both of these headphones became my main pairs, as they're both very complementary and have their own strengths. The HE-400's did very well for EDM - a significant upgrade over the Pro 750's (but still not the perfect sound I was looking for). They also have a more natural tonality that makes them excel with pretty much ALL genres of music. Surprisingly, the Q701's were also quite good all-rounders and offered their own unique portrayal of music (including EDM) - they actually hit low enough to make the bass enjoyable, they just somewhat lack presence/impact.
Pro 900 VERY First Impressions:
PC ----> USB ----> Matrix M-Stage DAC ----> Matrix M-Stage amp -----> Pro 900's
Foobar2000 playing 320kbps MP3 or FLAC (flat EQ)
These are very early first impressions of the Pro 900 - I've only listened to a few tracks - but it seems like these are what I've been looking for (when it comes to EDM). These Pro 900's have many hours on them, so burn-in shouldn't be a potential factor anymore.
The bass presence, impact and texture is phenomenal. I'm hearing elements in bass lines that I could never hear before. Normal, neutral audiophile headphones generally do NOT reproduce bass music adequately, and the Pro 900's are a testament to this. The treble is bright, clear and detailed - definitely emphasised, but not as much as the Pro 750's. These are very detailed headphones, but they aren't too sharp or aggressive for me - I think the Pro 750's are a bit too much. Mids are a little recessed, vocals aren't beautiful, but they aren't bad at all imo. The soundstage and imaging are excellent for closed headphones; the stereo separation on Ultrasone headphones have always been a strong point imo. The characteristics of these headphones make them EXCELLENT for bass-heavy electronic music, which is exactly what I want them for, and so far the only genre I've tested them on!
Some of the artists I've been listening to so far:
deadmau5
Spor
Feed Me (same guy as Spor)
Noisia
Flume
KOAN Sound
Gesaffelstein
Infected Mushroom
ZHU
RL Grime (I've never really liked trap, especially because no headphones I owned ever did it justice, but it's actually enjoyable with these)
