Short answer: the KEF R3. It ranks #15 of 222 bookshelf speakers by sound quality, rated 4.5/5, at $1,544.56; the Ascend Acoustics Sierra Duo V2 Ribbon ranks #64, rated 4.1/5, and costs $1,688, so there is not much of a tradeoff to weigh.
The KEF R3 is the more accurate, deeper-bass 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. Its measured preference score, a predictor of how neutral it sounds, is 6.20 against 4.53 for the Ascend Acoustics Sierra Duo V2 Ribbon. Its bass reaches about 58Hz before falling 3dB, against 79.1Hz for the Ascend Acoustics Sierra Duo V2 Ribbon. 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.
What the Ascend Acoustics Sierra Duo V2 Ribbon does well: A compact dual woofer bookshelf speaker with a ribbon tweeter, very consistent dispersion, and flexible vertical or horizontal mounting. The tradeoff: Bass measures 79.1Hz at -3dB, 64.5Hz at -6dB, and 43.9Hz at -12dB, and the 0.645dB on-axis average absolute deviation trails the Titan version’s 0.585dB.
Buy the KEF R3. It is rated higher for sound quality than the Ascend Acoustics Sierra Duo V2 Ribbon and costs less, so only choose the other one for a particular feature it does better.
Looking for alternatives? See the complete Passive Home rankings.
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Specifications Side By Side
| KEF R3 | Ascend Acoustics Sierra Duo V2 Ribbon | |
|---|---|---|
| Price | $1,544.56 per pair | $1,688 per pair |
| Ranked | #15 of 222 in Large Size Bookshelf Speakers | #64 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) | 79.1Hz (measured, spinorama.org) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | approximately 50Hz (measured, spinorama.org) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) | 86dB at 2.83V/1m anechoic |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier | 8 ohms nominal |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer | Two 4.5-inch glass-fiber woofers; custom RAAL true ribbon tweeter |
| Dimensions | 16.6”H x 7.9”W x 13.2”D | 16.25 x 5.75 x 6 in each |
| 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) | 4.53 |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) | 7.15 |
| DIY Kit | No | No |
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