Short answer: the Ascend Acoustics CBM-170 SE2. It ranks #113 of 222 bookshelf speakers by sound quality, rated 3.8/5, at $468. The Polk Signature Elite ES20 ranks #119, rated 3.7/5, at $398.98, $69.02 cheaper, which does not close the gap in sound quality.
The Ascend Acoustics CBM-170 SE2 is the more accurate choice. Compact two-way bookshelf speakers with a SEAS tweeter, a very flat midrange and smooth sound that suits most rooms. Its measured preference score, a predictor of how neutral it sounds, is 6.30 against 4.49 for the Polk Signature Elite ES20. The catch: 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 Polk Signature Elite ES20 is the deeper-bass option. Large, efficient bookshelf speakers with unusually deep bass for the price and wide horizontal coverage. Its bass reaches about 55.7Hz before falling 3dB, against 70Hz for the Ascend Acoustics CBM-170 SE2. Watch for: Predicted in-room smoothness of 0.238 and directivity-index consistency of 3.81 are average rather than class-leading.
Buy the Ascend Acoustics CBM-170 SE2. It is rated higher for sound quality, and the $69.02 you would save on the Polk Signature Elite ES20 does not close the gap.
Looking for alternatives? See the complete Passive Home rankings.
Compact two-way bookshelf speakers with a SEAS tweeter, a very flat midrange and smooth sound that suits most rooms.
Large, efficient bookshelf speakers with unusually deep bass for the price and wide horizontal coverage.
Prices on this page were last checked October 31, 2026 at 7:11 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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Specifications Side By Side
| Ascend Acoustics CBM-170 SE2 | Polk Signature Elite ES20 | |
|---|---|---|
| Price | $468 per pair | $398.98 per pair |
| Ranked | #113 of 222 in Large Size Bookshelf Speakers | #119 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | 55.7Hz (measured, ASR via spinorama.org) |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | 38.6Hz (derived, log-interpolated between spinorama.org -9dB/-12dB points) |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) | 86dB |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5” proprietary composite polygel cone woofer | 1” Terylene dome tweeter, 6.5” polypropylene woofer |
| Dimensions | 12H x 9W x 9.5D in | 14.8H x 8.5W x 13.8D in |
| Weight | 15 lbs (6.8 kg) each | 17 lbs (7.7 kg) each |
| Impedance | 8 ohms | 4/8-ohm compatible |
| Power Handling | 200W continuous, 400W peak | - |
| Woofer Cabinet | ported, rear | - |
| Spinorama Preference Score | 6.30 | 4.49 |
| Spinorama Preference Score with Perfect Sub | 8.66 | 6.44 |
| DIY Kit | No | No |
| Enclosure | - | 2-way, Power Port bass-reflex |
| Country | - | United States (design) |
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