I've just auditioned the sennheiser momentum at J&R today with my sansa fuze -> LOD -> E17. I made a playlist based off of the music that i've been listening to recently, which consisted mainly of electronic (touhou) as well as a few vocal, rock, metal, instrumental, and orchestral tracks. I will mainly be comparing these to my v-sonic GR07, my current IEM that I take around with me. I prefer a bright, and warm sound signature, like the sound provided by my dt880/600 powered by my decco2 & little dot mkiii. I've only started getting into the hi-fi hobby about two monthes ago, so please excuse my inexperience.
I have tried the m80, crossfade lp2, ath m50 and the hd-25 adidas. I definitely prefer the momentum's sound signature over those portables based off of memory. I can't really compare to the momentum to the other three very well, since i've only tried them for about 30 minutes each, and that was a while ago. For the record, those headphones were very uncomfortable for me to wear.
Comfort - I wear thick framed glasses, and the momentum clamped my glasses in a way that I couldn't move them unless i moved the headphones themselves. The leather is very soft, and would probably be very comfortable for those who don't wear glasses. I started experiencing pain on where my glasses' earpiece touches my head after about 30 minutes of usage. They momentum's earpads were mostly on my ear, not around it. On the other hand, the momentum was very nice around my neck; it was light, and the earcups were small enough to not bother my neck or chin.
Build quality - Solid metal, nice leather headband and earpads. The cable is pretty nice imo, it's thicker than most IEM cables, but not as thick as most full-sized headphones. It's also nice that the 3.5mm plug can be used straight or at an angle, and you can remove the cable for better portability
Soundstage - Decent soundstage for closed headphones, they sounded a little bit more closed than my dt770/250, more open than my gr07 of course.
Imaging - Pretty good separation of instruments, could tell where the instruments were in the orchestral tracks that I played.
Bass - Based on many impressions that i've read about the momentum, I first thought that these were supposed to be BASSY. But upon listening to them, I felt that they were fairly neutral to me, and definitely not as warm as the gr07. The momentum has a very pronounced mid-bass emphasis, and is very tight and punchy; never bloated or muddy. What I find lacking is the sub-bass. I could barely hear the low notes at all, unless I pushed the earcups into my ears more, which resulted in pain from my glasses.
Mids - Very forward compared to the gr07 and the dt880/600. Vocals were clear, and guitars sounded great. I like it! No complaints here.
Treble - As mentioned before, I like the brightness of the DT880/600 and I usually EQ my headphones to get the treble levels up to the dt880's. So usually I use +4 treble on my gr07, which is considered neutral, but slightly warm. I feel that the momentum has just about the right amount of treble for me. Very clean, and extended treble response, no sibilance to note of (im not very sensitive to it, but then again in used to the dt880's). Never harsh or fatiguing at all, awesome.
I really like the momentum's sound signature, except for the lack of sub-bass. I would not buy the momentum though, mainly because it's uncomfortable for me and I feel that the $349 retail price is way too high for the SQ that you get out of it, as I feel that the SQ is just slightly better than my gr07; maybe perhaps I would consider it if it were around $200.
I'm looking forward to impressions of the m100, as I liked the m80's sound signature. But if their comfort is anything like the LP2's, then it's a no-go for me.
