Ok, my entry here is comparing two sets of Sennheiser BT headphones - the Urbanite XL wireless and the Momentum 2 over-ear wireless. Currently undecided between both (been posting on the Momentum M2 thread). Hope the below is of interest.
First off, both have a pretty poor BT signal range in my experience. l exchanged the M2 once, and have bought the Urbanites and signal issues are the same. I am using a Sony Xperia Z3 compact. Files are all uncompressed FLAC files. Also used with a 2013 MacBook Air. Both sources use the Apt-X codec on BT signals. With either of the Sennheiser headphones (M2 or Urbanites), signal breaks up and stutters badly if I have the Xperia phone in my pocket. No issue with connection to laptop. Signal works well enough at home, though range seems quite weak. Others have not had this experience with BT stuttering, but can only share mine. I know that BT performance can be better than this, as have been using some Sony MBR-10RBT headphones with my Xperia compact without any signal issues at all, no matter where I carry my phone. Could it be linked to the BT 4.0 profile, as the Sony's are BT 3.0? Are Sennheiser throttling the power of the BT signal to give better battery life?
Anyway, on to impressions of both sets of headphones.
Momentum M2 wireless (over ear)
First, the Momentum M2s. These really look good, whether in ivory or black (had both, and preferred the ivory). Beautifully constructed with leather and stainless steel, lightweight and beautiful, soft ear cups made of leather and memory foam. The headband adjustment is excellent - no ratchets here, but a lovely slider on the ear cups to the stainless steel headband. They are also supplied in a cloth carry pouch and nice leather-style carry case, into which they fold for easier storage. They come with a wire for making a non-BT connection, a micro-USB charging cable and an airline adapter How do they sound? Well, that's not an easy question to answer. First, when it works, BT performance is pretty stunning. It is tied to Sennhesier's active noise cancelling, which is always on when using the BT connection. At home, this works so very well. Apart from a slight hiss, presence of ANC is not obvious, except in reducing ambient noise. Seems pretty good, but I'm more concerned on commenting on the sound of the M2s. These are a very lively sound signature - not at all flat or monitor like. My overriding sense is of warmth and richness. Bass (not my thing) seems tight, impactful and warm. Treble seems to have some sparkle and sheen to it - hence sense of excitement, and the midrange is best described as lush - hence this is a strange mix of warmth and speed, but certainly not uncoloured. Seems to project certain midrange material forward -e.g. voices, and bring them out of the mix. Given that these are portable phones, this is probably good news. It is the best sounding BT performance I could imagine - no obvious artefacts in the sound. Really does suggest that the apt-x codec works well and Sennheiser has done some wonderful work here.
Wired performance, to my ears, was more of a mixed bag. Bass (upper bass particularly) seemed to be richer and to bleed a little into the mid-range. Top end seemed a bit more open even. This is wired, without any ANC. The wired connection lead does not have a mic or remote - those functions only available in BT mode, using a rocker button on the right hand earpiece. I assume this is a limitation of the headphone socket, otherwise Sennhesier would have supplied an inline remote and mic like they do with the wired M2s. It is also possible to turn ANC on with the wired connection - this seems to make the sound signature closer to the BT performance. In all modes, sound staging seemed pretty good - wider than the headphones, but depth was harder to judge, possibly because the voicing emphasises certain details in recordings. So, a pretty good listen. Did not check microphone performance in voice dialling.
Now, my major concern is the ANC. I used it on public transport (a bus) and found that, to my ears, it seems to introduce some pitchy sounds to music playback. It was almost like a warbling on tracks. Quite distracting. This is an issue for BT, as ANC cannot be turned off - BT and ANC come as an indivisible package. It could have been the first set of headphones I used - have asked on another thread whether this is something others have experienced, but have not had any comments back yet. My second set had the same BT performance was the same as the first, and I did not test ANC on public transport with them. I did not find the wired connection sound balance to my liking without ANC, hence I took the second pair back, as seemed too expensive a headphone to have issues. So, bought the Urbanities.
Urbanite XL Wireless (over ear)
So, the Urbanities. Very different looking headphone that the Momentum - much heavier and bigger (the ear cups are large and round, not as tapered as the M2s) but not too big or too heavy. They have a similar headphone adjustment to the M2s - made of metal, though the ear cups are plastic. They also fold up. Uses a fabric foam cover on the ear pieces and what looks like silicon on the denim look headband. It's different, but still very well put together and I find them very comfortable on my ears. No carry case - just a thin, cloth bag, and he supplied accessories include a wired cable and micro-usb charging cable.
The Urbanites sound good. Duller than the M2s, but not as dark or recessed as some online reviewers suggest. Closer to classic Sennheiser sound signature (warm, with rolled off treble and solid midrange), but with slight lower bass emphasis and it appears a touch of zip in the upper treble (not completely rolled off). Certainly not a club tuned headphone, whatever the promotional materials say. BT performance is hiss free and clear, but same issues as M2 above re: stuttering with Xperia phone in pocket. It is still an excellent performance for a wireless headphone. Bass has good heft and impact, but I'm not a bass-head or EQ user. Does not rumble my skull, but clearly present. Soundstage is good for closed back headphone - laterally and in a sense of depth. Seem, surprisingly, to be well suited to most musical genres - consistent performance across the board. No ANC, but passive NC from close fit of headphones is good. Control of headphones is via a touch sensitive panel on the right earpiece. Tapping for function controls (e.g. one tap play/pause, two taps next track, etc) or sliding up or down for volume. Seems quite responsive, but also quite hit and miss - sometimes does not register double tap, for example. This could just be getting used to it, though, and the area of the touch pad is quite small.
The wired connection is worth mentioning, as it contains an inline remote button volume slider and microphone. The cable is rubberised, and the remote is twisted in the cable so that it sits off the right ear piece, which means it does not collide with clothing as easily (a nice touch). Thus, the supplied wire can control tracks and make calls without using BT (unlike the M2s). Sound quality improves with the wired connection too. The bass hits tighter and there appears to more delicacy and detail in the treble. Mids also seem a little less warm. It's not a night and day difference, but it is there, and it more a ringing endorsement of the basic quality of the BT signal that the difference is not vast. This is a headphone to be enjoyed wired or wireless.
M2 vs Urbanite?
I now face a tough decision. Whether to keep the Urbanite, or send it back and get the M2. The Urbanite is no slouch, but the M2 performance is richer and certainly more open and airy. Ironically, though, I'd suggest its sound signature is more obviously shaped than the Urbanite, despite the Urbanite being promoted as a 'bass' headphone. The Urbanite has an emphasis low down, yes, but is actually pretty balanced, M2 is much more obviously shaped in terms of sound curve, but in a pleasant way. So, in summary, I suppose despite some added emphasis on bass and some zip in the lower treble, the Urbanites are the more neutrally voiced of the two phones. The M2s sound cleaner and more transparent, given their voicing. The Urbanites are closer to a 'classic' Sennheiser sound, though the added bass emphasis is new. The M2 seems to be a slight re-voicing of the original Momentum, particularly in opening up the treble - I did not own the original momentum, but remember on demoing it that it sounded quite laid-back in the treble.
Anyway, hope these musings are of interest. I am looking for a travel companion, hence want something that can be BT and wired at the same time, and give decent performance through both. I tend to carry a bag most days, and if I put my phone in there, have less stuttering issues with BT than when the phone is in my pocket with either Senn headphones. Both of these are close to what I want - just need to decide between them. In UK, where I live, M2 wireless is £379, whereas the Urbanite wireless goes for £250. Neither cheap, but both versatile. I'm not after a portable monitor - want something that sounds good across most genre and is easy to drive. At home, I do critical headphone listening through Sennheiser HD700s and HD650s, allied to a Burson headphone amp and Cyrus and Rega hifi system. Not looking for similar type of performance in my portable life, so one of these is likely to do me well. Both excellent headphones, though I do wish Sennheiser would do something about the BT signal and stuttering. There is a suggestion that both can be updated via firmware. Let's hope this is true.