My thoughts after a day and a half of listening...
Comfort wise, I'm happy to report that the Momentums work very well for me... and I tend to be very picky on comfort as well (as noted here for reference: http://www.head-fi.org/t/634691/the-comfort-thread-rate-the-comfort-factor-of-your-headphones#post_8856613). Sennheiser has always had well-fitting headbands for my head and Momentum is no exception... they curve perfectly on top of my head, distributing the pressure very evenly. I think perhaps the pad on the headband could have been softer but the headphones are light enough that I hardly feel it at all. Clamping wise, they're firm but comfortable enough.. (and when I wear a hat outside and wear these over them, the clamping is even lesser) I'd say the clamping is on par with the M50's that I used to have. Thankfully I have small ears as noted on the link above, so the pads DO go around my entire ear... albeit it is very, very crammed in there (so this may likely be an issue in the summer when it gets hot, etc). The Momentums will likely be semi on-ears for most people I'd think. Pads are a bit stiff out of the box, but remembering the demo units they should get worked in soon enough. Overall, they're much more comfortable than the HD25's for me. I wore these for hours at a time last night without much issues.
The packaging is very nice, and they include a carrying case, an extra cable and a 1/4 plug adapter. It's a good thing that they include a remoteless cable, though... as I feel that the remote control on the default cable of the Momentums are unnecessarily too big and heavy. I realize they used metal there for durability reasons, but IMO it weighs the cable down noticeably, enough to be of a nuisance at times. And I'm not sure if it is just my cable, but the remote control on my Momentum doesn't seem to work particularly well... I'd press the center button twice to skip forward but lots of times, it would merely pause the music... The included case, while solid, will likely never see much practical use for most people IMO... it's way too big to carry around in a briefcase or a laptop bag and such.
Design wise these are a real winner. Pictures says it all really... Much, much better looking than the HD25's which are frankly, well... ugly... and WILL get you curious looks when you wear it out. I usually use portable headphones when I'm out and about at work and the Momentums without a doubt look much classier in a business suit or more formal outfits. The HD25's.. clearly look out of place in such situations (though I've always worn it out and about anyway... can't say I'm all that fashion conscious ).
Sound wise... compared to my incumbent HD25-1 II's... it's definitely a different sound. I'm hesitant to say that one is outright better than the other here... I think each of them just goes about the sound in a different way at the same level of overall quality. I've noticed following differences between the two:
- The Momentums have a recessed lower treble/upper midrange to my ears, IMO just a little bit too much... to make things sound too "blunt" or "boring" on certain tracks. IMO the HD25's are much more of an exciting and fun sounding headphone, as they're opposite of the Momentums and have a boosted lower treble/upper midrange instead. Then again, this both comes with a benefit and a tradeoff... Momentums for example will almost NEVER become sibilant but HD25's definitely do have the tendency to become so on many tracks. So here it really depends on what you are looking for... a more forward, and exciting approach to music (in which case HD25's would be better) or a laid back one (the Momentums).
- HD25's also have bit more of a tighter bass, but have a recessed lower bass (likely because they're on ears). Momentum's bass is a tad too loose in the midbass region I feel, but it also extends lower than the HD25's. This is also part of what contributes to the "blunt" sound I mentioned earlier sometimes as well.
- HD25's extend higher in the high frequencies and is more elevated in this region overall, but this also makes them a bit harsh on some tracks. Highs on the Momentums exist but are shelved back... so this would really come down to how tolerant one is to high frequencies.
- The Momentums IMO are much smoother and cleaner throughout the entire range, which HD25 definitely do have some grainy sound to them. In terms of detail retrieval both seem about the same, though HD25's elevated treble may give you an illusion of those being more detailed. Momentums seems to have better instrument separation to me, while on HD25 things sound a little too mushed together.
- The Momentums are much more open sounding in the soundstage department. HD25's are nearly IEM-like in how intimately sounding they are.
So to sum it up,
Momentums: Relaxed, open, laid back, but at times a bit 'blunt' in overall presentation.
HD25's: Forward, intimate, energetic, but sometimes a bit too aggressive and closed in.
Overall, it's hard for me to say right now on which of the two headphones will survive in my collection... while I love many aspects of the Momentums (comfort, design, smooth, laid back sound), HD25's also sound great in its own way (forward, energetic, fun sound) as well, and also feel that HD25's are tad more portable friendly (it has more of that 'toss in the bag and forget about it cuz it's so damn tough and rugged' feel to them, and is smaller overall). To be honest, purely on the sound quality aspect alone, what I'm hearing is more of a $150~$300 range sound, similar to the HD25's level (I paid $400+tax CDN retail for the Momentums here)... but they do have other advantages such as design, comfort and extras which have to be considered. So I'll just have to do more listening over the next week or so and decide...
Edited by K_19 - 11/12/12 at 11:19am