Much to the chagrin of my wallet I went out and bought the Kef M500 and B&W P7 this week. To start with I think both sound better than the Momentum, so to some degree you're actually getting what you pay for with them in terms of sound. What both M500 and P7 do better than the Momentum is bass control. It just feels like the M500 and P7 are stiffer and better dampened constructions, while the Momentum has some resonance that bleed into the mids a bit.
The P7 is a huge improvement over the P5, since it now has a more present treble and properly big soundstage. The treble is still slightly dampened, so there's no harshness whatsoever. But it sounds like a more neutral balance than the other B&W headphones. The bass has a bump in it which adds some nice impact and oomph, without becoming ridiculous and overpowered. The bass bump is bigger than the one in the Momentum, so the Sennheiser's remain the more balanced headphone of the two. What the P7 do better though is have a big bass that still feels well controlled, so the mids and highs retain clarity even when there's a huge pulsing bass in the background. This is something the M500 do as well. The M500 seem to have a more linear balance than the Momentum and P7, except with a bump in the deep bass instead of mid bass. So with electronic music you can get a huge pulsing deep bass with the M500 at times, and thanks to the tightness of the sound you still have a wide open soundstage and midrange clarity. Of the three the M500 has more treble and can at times have a hard quality to the highs. There's no sibilance from what I've heard, so they're still nice to listen to over time.
Overall the Momentum are of course still a nicely balanced and well done headphone, but personally I like the M500 and P7 more. Between the M500 and P7 I can't decide yet, but I'm leaning toward the P7 since they're more nicely built and are more comfortable. If you had to pick one of the three there's no wrong choice. They're all excellent, and I'm impressed by the quality of the closed headphones in this category now. Many companies are clearly working their butts off to make the best headphone possible. Great times.
Thanks for your impressions! I only got to give the P7 a quick listen myself and wasn't really impressed when I did. But it was also in a noisy store, so that sort of ruined it anyway. As for your observations on the M500, I agree with you there. For me, comfort was the reason to not pick the M500. I mean, it's a very comfortable headphone, but just not for extended listening (for me). But your observations have intrigued me to give the P7 a closer listen (several hours, to get a proper impression).
And I definitely agree on your observations of the bass in the M500, it's a very well defined tight bass, that reaches very deep when the music asks for it. A very gorgeous bass if you ask me, especially with electronic music.
[by the way, received my brown Momentums today, and so far enjoying every minute of it ]
Edited by starfly - 10/4/13 at 7:14am