KEF C3 Bookshelf Speaker
Audio cognoscenti won't recognize the C3 ($350/pr) as a KEF because it doesn't have KEF's trademark concentric tweeter-inside-woofer design. Its 0.75-inch aluminum-dome tweeter sits above its 5.25-inch polypropylene-cone woofer in an 11.4-inch-high front-ported cabinet.
"This is the speaker you want if you're going to have friends over and put some music on and crank it up," Lauren said. "It's really good for disco, hip-hop, pop, and rock, because the sound holds together really well at high volume." My notes arrived in the same place from a different angle: I thought that while the overall balance was fairly flat, the bass was pleasantly pumped-up, the upper mids and highs sounded unusually vivid, and the sense of space was excellent. "A fun voicing!" I concluded.
Geoff demurred, saying the bass was too fat'n'loose for his taste and complaining about a too-forward upper midrange and too-soft upper treble. I was a little annoyed at what sounded like a resonance in the front baffle, causing a bit of bloat in the lower midrange and a mild "cupped hands" coloration in vocals, as if singers were lightly cupping their hands around their mouths. (The ringing sound I heard when I rapped a knuckle against the plastic-covered front baffle seemed to confirm my guess.)
Obviously, the C3 flouts some of the rules of speaker design - specifically, that a speaker should ideally have a flat frequency response and a neutral sound. But even a doctrinaire, lab-coat-wearing fuddy-duddy like me can appreciate a speaker that delivers fun when fun is demanded. (In fact, I wish I were better at that task.) The C3's not for audiophiles, in our opinion, but we think a lot of people will love its vivid, exciting sound.
Frequency response of the KEF C3 measures 60 Hz to 20 kHz ±4.7 dB on-axis, ±4.8 dB avg 0°-30°. It's an impressively flat response except for a narrow (probably inaudible) dip at 770 Hz, and a couple of fairly substantial peaks at 1.9 and 2.5 kHz. Measured impedance is 5.0 ohms minimum, 8 ohms average. Sensitivity from 300 Hz to 10 kHz averages 84.3 dB.