Short answer: the AsciLab C6B. It ranks #6 of 222 bookshelf speakers by sound quality, rated 4.7/5, at $1,145; the KEF R3 ranks #15, rated 4.5/5, and costs $1,544.56, so there is not much of a tradeoff to weigh.
What the AsciLab C6B does well: Bookshelf speakers with very accurate sound and an unusually wide, stable soundstage, for any seating position. The tradeoff: Bass rolls off around 50Hz in-room (F3 54Hz, F10 35Hz), so a subwoofer is needed for real extension below that.
Why pick the KEF R3: A three way bookshelf speaker with KEF’s coaxial driver for stable imaging across seats and very low distortion, easy to run with a modest amp. The catch: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover.
Buy the AsciLab C6B. It is rated higher for sound quality than the KEF R3 and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Looking for alternatives? See the complete Passive Home rankings.
Bookshelf speakers with very accurate sound and an unusually wide, stable soundstage, for any seating position.
A three way bookshelf speaker with KEF’s coaxial driver for stable imaging across seats and very low distortion, easy to run with a modest amp.
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Specifications Side By Side
| AsciLab C6B | KEF R3 | |
|---|---|---|
| Price | $1145 per pair | $1,544.56 per pair |
| Ranked | #6 of 222 in Large Size Bookshelf Speakers | #15 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 35Hz (measured, Erin’s Audio Corner) | 35.2Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) |
| Dimensions | 15.7”H x 8”W x 10.4”D (398.8 x 203.2 x 264.2 mm) | 16.6”H x 7.9”W x 13.2”D |
| Impedance | 4 ohms nominal, 2.6 ohms minimum (measured, Erin’s Audio Corner) | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier |
| Sensitivity | 85.6dB (measured, Erin’s Audio Corner) | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Drivers | 6” Aluminium Ceramic Cone with cast Aluminium Chassis woofer, 1” Aluminium Ceramic Dome tweeter | 1” tweeter coaxial with 5” midrange; 6.5” woofer |
| Weight | 18.5 lbs (8.4 kg) each | 29.9 lbs (13.55 kg) each |
| Woofer Cabinet | passive radiator | ported, rear Flexible Port |
| Spinorama Preference Score | 6.33 | 6.2 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 8.28 | 7.97 (spinorama.org) |
| DIY Kit | No | No |
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