Short answer: the Emotiva Airmotiv XB2. It ranks #49 of 222 bookshelf speakers by sound quality, rated 4.2/5, at $549. The Ascend Acoustics CBM-170 SE2 ranks #114, rated 3.8/5, at $468, $81 cheaper, a saving that is not big enough to make up the sound-quality gap.
The Ascend Acoustics CBM-170 SE2 is the more accurate choice. On-axis response is impressively flat from about 100Hz to 2kHz, staying within roughly ±1dB, with a clean, gradual bass rolloff below that. Its measured preference score, a predictor of how neutral it sounds, is 6.30 against 5.65 for the Emotiva Airmotiv XB2. Watch for: A narrow dip in the on-axis and listening-window response appears in the 3-5kHz range (down to about -2.7dB), mirrored by a matching dip in the directivity index at the same frequencies: likely a brief widening of dispersion right at the tweeter/woofer crossover.
The Emotiva Airmotiv XB2 is the better-sounding, deeper-bass option. Very neutral, linear frequency response at the recommended toe-out angle, with better directivity than the similarly-priced ELAC Debut 3.0 DB63. Its bass reaches about 62Hz before falling 3dB, against 70Hz for the Ascend Acoustics CBM-170 SE2. The tradeoff: Slight recessed upper-midrange around 2kHz from the tweeter-to-woofer handoff.
Buy the Emotiva Airmotiv XB2. It is rated higher for sound quality, and saving $81 with the Ascend Acoustics CBM-170 SE2 does not make up for the sound-quality gap.
Still deciding? The full Passive Home rankings cover every ranked option.
On-axis response is impressively flat from about 100Hz to 2kHz, staying within roughly ±1dB, with a clean, gradual bass rolloff below that.
Ascend Acoustics $468 eBay
Very neutral, linear frequency response at the recommended toe-out angle, with better directivity than the similarly-priced ELAC Debut 3.0 DB63.
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Specifications Side By Side
| Ascend Acoustics CBM-170 SE2 | Emotiva Airmotiv XB2 | |
|---|---|---|
| Price | $468 per pair | $549 per pair |
| Ranked | #114 of 222 in Large Size Bookshelf Speakers | #49 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | 62Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | 43Hz (measured, Erin’s Audio Corner) |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) | 86dB (2.83V/1m, Manufacturer specified) |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5” proprietary composite polygel cone woofer | 1x 6” woven cone woofer, 1x 25x32mm AMT folded ribbon tweeter |
| Dimensions | 12H x 9W x 9.5D in | 12.8” x 8.5” x 11.5” (325 x 216 x 292 mm) |
| Weight | 15 lbs (6.8 kg) each | 18.1 lbs (8.2 kg) |
| Impedance | 8 ohms | 4 ohms nominal (safe with 8-ohm rated amps) |
| Power Handling | 200W continuous, 400W peak | 125W continuous, 200W peak |
| Woofer Cabinet | ported, rear | Bass reflex, rear ported |
| Spinorama Preference Score | 6.30 | 5.65 |
| Spinorama Preference Score with Perfect Sub | 8.66 | 7.93 |
| DIY Kit | No | No |
| Frequency Response | - | 48Hz - 27kHz (+3/-3dB, Manufacturer specified) |
| Crossover Frequency | - | 2.6kHz |
Frequency Response Compared
Both speakers’ spinorama measurements, overlaid. A flatter line is more neutral: peaks sound forward or harsh, dips sound recessed. Each curve is shifted so its average from 300 Hz to 3 kHz sits at 0 dB, so loudness differences between the two are removed and only the shape is compared. The two were measured by different sources, so small differences, especially in the bass, can come from the measurement setup rather than the speakers.
Measurement data: Ascend Acoustics CBM-170 SE2 (measured by the manufacturer) and Emotiva Airmotiv XB2 (measured by Erin’s Audio Corner), via spinorama.org.
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