Short answer: a tie on sound quality. Both are rated 4.5/5 (#15 and #20 of 222 bookshelf speakers), so choose on features and fit.
The KEF R3 is the more accurate, deeper-bass choice. 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. Its measured preference score, a predictor of how neutral it sounds, is 6.20 against 5.24 for the AsciLab F6Bs. Its bass reaches about 58Hz before falling 3dB, against 82Hz for the AsciLab F6Bs. 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.
The case for the AsciLab F6Bs: A slim, sealed bookshelf speaker that mounts flat on a wall bracket, with accurate sound and wide, even dispersion for a great price. The tradeoff: AsciLab’s own site shows the F6Bs sold out, though it remains in stock through resellers like Audiophonics and Tested Audio.
Buy the KEF R3 or the AsciLab F6Bs on features: they are rated the same for sound quality at close to the same price.
Still deciding? The full Passive Home rankings cover every ranked option.
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.
A slim, sealed bookshelf speaker that mounts flat on a wall bracket, with accurate sound and wide, even dispersion for a great price.
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Specifications Side By Side
| KEF R3 | AsciLab F6Bs | |
|---|---|---|
| Price | $1,544.56 per pair | €799 per pair |
| Ranked | #15 of 222 in Large Size Bookshelf Speakers | #20 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) | 82.0Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | 50.1Hz (measured, Audio Science Review) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) | 85.2dB @ 2.83V/1m (measured, Audio Science Review) |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier | 4 ohms nominal, 3.7 ohms minimum |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer | 1” aluminum dome tweeter with waveguide and phase plug, 6” fiber cone woofer |
| Dimensions | 16.6”H x 7.9”W x 13.2”D | 14.5”H x 8”W x 6.1”D (368 x 203 x 154 mm) |
| Woofer Cabinet | ported, rear Flexible Port | - |
| Weight | 29.9 lbs (13.55 kg) each | 12.3 lbs (5.6 kg) each |
| Spinorama Preference Score | 6.2 (spinorama.org) | 5.24 |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) | 7.90 |
| DIY Kit | No | No |
| Enclosure | - | sealed |
| Crossover Frequency | - | 1kHz |
| Mounting | - | VESA 100 wall mount compatible |
| Warranty | - | 2 years |
| Country | - | South Korea |
| Maximum SPL | - | 100dB full bandwidth, 102dB above 100Hz (manufacturer specified) |
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