Review: Bowers & Wilkins C5

If you’re sick of trying to choose among dozens of lookalike IEMs in the racks at electronics stores, you’ll find the C5 to be welcome relief. This IEM resembles nothing else on the market. The back of each titanium earpiece holds B&W’s Micro Porous Filter, a layer of hundreds of tiny steel balls that the company says works as a sonic diffuser. Each of the two cables slides through its earpiece to form an adjustable loop that fills your pinna to keep the C5 in place.

The C5 includes a cool little half-moon-shaped case with a leather thing inside that you can use to keep the cable neatly wound. The inline control/microphone is compatible with iPhones. Four pairs of silicon tips are included, one of which is unusually conical.

All of us found the C5 initially difficult to fit into our ears, but after an adjustment period that took between 5 minutes for Greg and about 1 hour for me, we got a fit that Greg called “insanely comfortable.” The adjustable cable loop makes them exceptionally secure.

“Can I keep them?” Lauren responded when I asked her about the sound quality. She and Greg both raved about the C5’s neutral tonal balance and overall fidelity. Geoffrey Morrison liked them so much that he bought himself a pair for his trip to Africa. I found low bass to be a little emphasized — the kick drum on the Cult’s “King Contrary Man” sounded overly powerful — but in general thought the sound was at least the equal of any IEM I’ve heard, short of expensive multidriver, custom-molded designs. The clarity of the piano and percussion on Steely Dan’s “Aja” matched what I’ve experienced with very good high-end speaker systems. I especially loved the treble’s rare blend of smoothness and detail.

This beautifully designed, fantastic-sounding product is one of the best IEMs we’ve encountered. At $180, it’s a steal. 

Test Bench

The C5’s response plot shows a bass-heavy balance with a strong peak centered at 3.4 kHz. Increasing output impedance to 75 ohms produces almost no change in the frequency response. Isolation is typical for an IEM. Distortion at 100 dBA tends to run below 1% but rises to 2.5% at 20 Hz. Average sensitivity from 300 Hz to 10 kHz with a 1-watt signal at the rated 32 ohms impedance is 104.6 dB.