Short answer: the AsciLab F6B. It ranks #12 of 222 bookshelf speakers by sound quality, rated 4.6/5, at $980; the KEF R3 ranks #15, rated 4.5/5, and costs $1,544.56, so there is not much of a tradeoff to weigh.
Why pick the AsciLab F6B: A great value bookshelf speaker with accurate, well balanced sound and punchy midbass that gives kick drums extra impact. The tradeoff: A mild sibilance-inducing lift around 6-8kHz, most noticeable on female vocals, paired with a shallow dip in the upper midrange: correctable with a simple 3-band EQ the reviewer provided.
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. Watch for: 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 F6B. It is rated higher for sound quality than the KEF R3 and costs less, so only choose the other one for a particular feature it does better.
Still deciding? The full Passive Home rankings cover every ranked option.
Measured Differences
- Close enough not to matter: bass extension (38 Hz vs 35.2 Hz, 10 dB down).
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Specifications Side By Side
| AsciLab F6B | KEF R3 | |
|---|---|---|
| Price | $980 per pair | $1,544.56 per pair |
| Ranked | #12 of 222 in Large Size Bookshelf Speakers | #15 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 38Hz (measured, Erin’s Audio Corner) | 35.2Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 56Hz (measured, Erin’s Audio Corner) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) |
| Dimensions | 15.7” x 8” x 10.4” (400 x 203 x 265 mm) | 16.6”H x 7.9”W x 13.2”D |
| Impedance | 4 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin’s Audio Corner) | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier |
| Sensitivity | 85dB (2.83V/1m, measured by Erin’s Audio Corner) | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Drivers | 1” aluminum dome tweeter, 6” fiber cone woofer | 1” tweeter coaxial with 5” midrange; 6.5” woofer |
| Weight | 16.5 lbs (7.5 kg) each | 29.9 lbs (13.55 kg) each |
| Woofer Cabinet | Passive radiator loaded | ported, rear Flexible Port |
| Crossover Frequency | 1000Hz | - |
| Recommended Power | up to 125W | - |
| Spinorama Preference Score | 6.32 | 6.2 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 8.26 | 7.97 (spinorama.org) |
| DIY Kit | No | No |
Where the Ratings Come From
- AsciLab F6B: Spinorama.org measurements and reviews by Erin’s Audio Corner.
- KEF R3: Spinorama.org measurements and reviews by Erin’s Audio Corner and 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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