• Signal cable length: Some reviewers feel the C5’s signal cable is too short—comments that frankly make no sense to me. The signal cable on my review samples measured approximately 44” from mini-jack to earpieces, which is plenty long enough to allow even tall listeners to connect the C5 to an iPhone carried in pants pockets, etc., with ample slack in the cable left over.
• Fit: Some reviewers have found the C5 difficult to fit and have argued that it could benefit from a broader range of ear tips. Obviously there are significant individual differences in ear canal size and shape, so that one man’s “ideal fit” could be another man’s “not-so-good fit.” Even so, I would point out that the C5 already comes with four sizes of ear tips, rather than the usual three sizes many manufacturers provide. Bear in mind, though, that the only way to get an optimal fit with the C5 is to use the secure loop system properly.
• Noise isolation: The C5 is not the last word in noise isolation, nor does it try to be. With the C5, noise isolation is good, but by design the earphone does allow some ambient noise to pass through. If you require extreme levels of noise isolation, you’ll want to look further.
• Tonal balance: Reviewers’ comments on the C5’s tonal balance have been mixed, some finding that it has a bass-forward sound, while other finding it to be more lightly balanced. My take on the matter is that the C5 is quite sensitive to overall fit and ear tip sizing, meaning that even fairly small adjustments in positioning of the secure loop (or changes in ear tips) can a surprisingly big impact on the C5’s overall sound. Thus, users will discover they can “fine tune” the C5’s tonal balance to achieve a presentation that is reasonably neutrally balanced and that offers very, very good measures of openness and expressiveness
Heard at its best, the B&W C5’s sound is pleasingly expressive, open, and transparent—especially in the vital midrange and upper midrange regions. More so than many competitors, the C5 is good at revealing subtle (and sometimes not-so-subtle) shifts in dynamic emphasis in the music, which give the earphone that desirable ability to “breathe” and respond to the ebb and flow of energy in the music. By comparison, many ‘phones sound a bit compressed, almost as if they are persistently “throttling” the dynamic range of the music. Not so the C5; when instrumentalists or vocalists choose to emphasize a particular note or phrase, the B&W’s will let you know what’s happening right away and in no uncertain terms. In short, the C5’s manage to sound appropriately vivid, yet unexaggerated.

The C5’s highs offer a combination of good clarity and natural warmth, though they may sound just a touch dry. But with that said, let me also point out that the C5’s treble response is also blessedly free from edginess or glare. As a result, the C5 sounds quite transparent and nicely extended, yet without ever becoming sterile, aggressively piercing, or analytical.
The bass of the C5 is always clear, well defined, and well-controlled, though overall bass balance can and does vary as a function of fit in general and ear tip sizing in particular. I tried the C5’s both with large ear tips (the size I would normally use with most earphones) and with the next smaller size of ear tips (which is something the C5’s inventive secure loop system allowed me to do while still getting a good seal).
With the larger ear tips in place, bass was clean and powerful, but pushed forward in the mix somewhat, making midrange frequencies sound slightly recessed by comparison. I frankly think that many listeners—and especially those who favor bass-centric styles of music—would love this sound at first listen, even though it might not offer maximum levels of accuracy. One small drawback, though, was that the larger ear tips seemed to suppress some of the C5’s delightful ability to “breathe” and flow with the music.
With the next smaller size of ear tips in place, however, tonal balance arguably became more accurate, albeit at the expense of somewhat diminished bass weighting and mids that were perhaps just a touch too forward-sounding. On the whole, though, I think most accuracy-oriented purists would prefer the sort of sound I enjoyed with the smaller ear tips installed. Bass remained punchy, articulate and well extended, while mids were better-proportioned relative to the low end. What is more, the C5’s midrange really bloomed with the smaller ear tips installed, sounding noticeably more nuanced and dynamically alive. This, I feel, is really the true sound of the C5—the sound that makes this headphone special within its class. Indeed, the C5 reminded me more than a little of the sound of one of Playback’s favorite earphones in this price bracket: namely, Phonak’s superb PFE 122. Both ‘phones are characterized by a more nuanced and sophisticated sound than you might expect for the money, although their voicing is by no means identical. The key point to bear in mind, however, is that the C5 may require experimentation with fit and ear tip sizing in order to deliver its full sonic potential.