Short answer: a tie on sound quality. Both are rated 4.5/5 (#15 and #18 of 222 bookshelf speakers), so choose on features and fit.
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 tradeoff: 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 AsciLab A6B Passive is the deeper-bass pick. A sealed bookshelf speaker with a Purifi woofer and passive radiators, essentially flat response, and solid bass for its size. Its bass reaches about 41Hz before falling 3dB, against 58Hz for the KEF R3. Watch for: 4 ohm nominal impedance and 82dB sensitivity call for a robust amplifier.
Buy the KEF R3 or the AsciLab A6B Passive 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.
Measured Differences
- Efficiency: the KEF R3 is rated at 86 dB sensitivity against 82 dB for the AsciLab A6B Passive, so it plays as loud with roughly half the amplifier power.
- Close enough not to matter: bass extension (35.2 Hz vs 34.7 Hz, 10 dB down).
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Specifications Side By Side
| KEF R3 | AsciLab A6B Passive | |
|---|---|---|
| Price | $1,544.56 per pair | €3,790 per pair |
| Ranked | #15 of 222 in Large Size Bookshelf Speakers | #18 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) | 41.0Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | 34.7Hz (measured, Audio Science Review) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) | 82dB @ 2.83V/1m |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier | 4 ohms nominal |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer | 1” dome tweeter, 6.5” Purifi aluminum cone woofer, 2x 6.5” Purifi passive radiators |
| Dimensions | 16.6”H x 7.9”W x 13.2”D | 15.9”H x 8.7”W x 11.8”D (405 x 220 x 300 mm) |
| Woofer Cabinet | ported, rear Flexible Port | - |
| Weight | 29.9 lbs (13.55 kg) each | 27.1 lbs (12.3 kg) each |
| Spinorama Preference Score | 6.2 (spinorama.org) | 6.50 |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) | 8.24 |
| DIY Kit | No | No |
| Enclosure | - | sealed with passive radiators |
| Crossover Frequency | - | 1kHz |
| Warranty | - | 2 years |
| Country | - | South Korea |
| Maximum SPL | - | 102dB full bandwidth, 106dB above 100Hz (manufacturer specified) |
Where the Ratings Come From
- KEF R3: Spinorama.org measurements and reviews by Erin’s Audio Corner and Audio Science Review.
- AsciLab A6B Passive: Spinorama.org measurements and reviews by Audio Science Review.
This comparison is generated from the ratings, specifications and measurements on each product’s own page, and it updates when that data changes. How we rank explains how each rating is decided.
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