Here is another impression of the B&W C5s (by me):
I've owned these for 24 hours only. I have good experience with the following IEMs: Etymotic ER4p,Etymotic HF5, Shure SE530, Hifiman RE0, UE TripleFi10, Audio Technica CK-10, Klipsch S4. That's right, don't mess around, go straight towards the top tier or go for bang for the buck. No in-between. I am not an audiophile, but I keep searching for the ideal IEM b/c I listen on the go most of the time.
The First Listen
When I first put these in, I was like oh gross. A huge bass hump/overpowering, and very muddy. For what it's worth, I put alot of stock into a first listen, but that's something that I probably need to unlearn. I bought the Klipsch S4 on faith b/c people said it was so good for the money, and even tried the X10 as well. I felt that those models were again, all bass, muddy, and just unrefined. Who would want to listen to this? The C5, I feared, was headed into Klipsch S4 territory again.
But I powered through it. I quickly realized that a huge bass presence, and an even overpowering one, doesn't mean that the other frequencies are not there. This is in contrast with the Klipsch S4, which I still feel like had no other frequencies present. I found that on an iDevice (iPhone) if you change the EQ to Bass Reducer, the C5 sounds more balanced, dare I say it, almost normal. And I don't usually believe in EQs, (no technical claim to back that up); it's just that crap is still crap, and quality will remain quality with/without EQ. But it does seem like if you are able to reduce the Bass, the C5s are good because again, everything is there. What I noticed was that the bass is EASILY the most plentiful of any IEM I have ever heard, and I will stand by that statement.
The sound, probably b/c of the bass, is extremely thick and syrupy. This is most apparent if you switch to Etymotics right afterwards. By comparison, other IEMs sound thin, shrill, and weak. I can only imagine that the Sennheiser IE8 could give these a run for their money. I have never had the ability to pick out the entire bass lines, with perfect clarity. The C5s really emphasize bass to subwoofer levels. I'm not used to that. At all.
The second thing that I noticed that the soundstage is huge. We're talking TripleFi10 huge. Is it the Tungsten ball bearing dispersion? Who knows? But I immediately noticed pieces of music that I hadn't ever heard before. I think twice I have turned my head b/c I thought someone on the right knocked my door in real life. That was the music. That's a great feeling to have. With electronic music, which likes to sweep say, a synth from left to right, it's really nice. I feel like I can feel my ears following from left to right. I love a great soundstage. The soundstage is larger than any of the IEMs that I listed above. If you would like a word on the mids and highs. Singer's voices sound farther away, but I would not call it recessed? It's not in your ear, or "forward", as people call it. But I don't feel like I am straining to hear the vocals, nor would I say that they are muddy. If there's muddiness, it's b/c the bass is so heavy. The highs are there as well, and you can hear echo/reverb, but they do not sparkle as much as the TripleFi10. Then again, nothing does.
Brain Burn-in
That said, there is brain burn-in, and the C5s now don't sound so bass heavy. The sound that they produce appears to be more balanced now. I think that my final verdict is that the C5s will be a matter of taste, as opposed to a matter of being a flawed IEM. It's like some people like red wine, others white. I would recommend the C5 unequivocally to bass heads. You're not getting any more bass in IEMs, period. And for say, hip hop, the C5s seem to shine. For ballads that rely on breathy, sparkly female shimmering and reverb, the C5s actually have all of that. But it's like you have a 10th row seat for it. To me, that's different than some IEMs that would never pick up on the shimmer and reverb and the spatial cues. What I'm trying to say that with regards to the 3D effect that I covet alot, the C5s are like a darker TripleFi. Etymotics, and the Shures, and the RE0s, are not even eligible to be considering the 3D effect to me.
Overall Sound Signature
Warm, bass heavy, great soundstage, very energetic but impossible to be accused of being bright. Based on what I've read, it seems like the C5s may be similar to the IE8s by Sennheiser.
Fit
I find them to be comfortable, and this is a miracle considering my small ear canals. The C5s are, quite frankly, sausages. Big, thick, Inner Ear Sausages. These are as big as the legendary TripleFi10, which I could NEVER fit into my ears no matter what type of tips I tried. The B&Ws, for whatever reason do fit, and they fit well. The secure loop invention is not a gimmick. They secure the C5s very well. The problem is, I think that it's a very hit/miss thing. In other words, if your ears can fit and the secure loop jives with your ear shape, then you will love the comfort. But I could see how some people would say the C5s are uncomfortable. However, I fail to see how anyone could find the TripleFi10 comfortable.
What I'm going to do:
I will be returning these because I simply value treble extension, and clearer vocals than the C5 provides. I feel like the C5s are, despite everything being there, not as balanced as I prefer, even after brain burn-in (well, it's only been 24 hours). The best IEMs I have heard are the TripleFi10s based on pure sound alone or the CK10, but I've given up b/c of fit. It does you no good to have a great IEM if you can't wear it. Just like in the photography world, owning a great but bulky SLR is no good if you never carry it with you. The Audio Technica CK-10 is the ticket for me right now. Now when / if Logitech makes a TripleFi10 successor, and I have to assume that they know that they need to shrink things down, then I'll be very intersted. But for an overall package, the CK-10s (and probably the CK100s) are the best that I have heard.
If you're at all flexible and don't have to have IEMs but want a very portable headphone, I would get the P5 in a heartbeat over the C5s, and it's not just b/c they are headphones vs IEMS, so they should sound better. There's just no huge overpowering bass presence.
Value
The asking price of $179.99 is appropriate. I think that these are definitely worth that regardless of which company made them. I think that for the basshead, the C5s will be well worth the money. I consider them to be just short of the top tier of IEMs. They've made the cut to get into the IEM Olympics, but they aren't going to medal. $179 is not very expensive for IEMs these days, and there more expensive IEMs that perform more poorly. Just like there are cheaper IEMs that perform better. So we'll call the value proposition acceptable.