Short answer: the Ascend CBM-170 SE2 on measured sound quality, the Polk Signature Elite ES20 on price. The Ascend CBM-170 SE2 ranks #66 of 130 bookshelf speakers at $468. The Polk Signature Elite ES20 ranks #69 at $359, $109 cheaper.
What the Ascend CBM-170 SE2 offers: On-axis response is impressively flat from about 100Hz to 2kHz, staying within roughly ±1dB, with a clean, gradual bass rolloff below that. The directivity index rises smoothly and predictably through the crossover region, and the estimated in-room response shows a smooth, consistent downward tilt from 100Hz to 10kHz with no major discontinuities - close to the ideal in-room target shape. Measured sensitivity of 86.8dB nearly matches Ascend’s 87dB spec. The manufacturer’s own preference-score modeling comes out to 5.81 unequalized (rising to 8.17 with an ideal subwoofer, or 6.33/8.41 with EQ applied) - a strong result for a compact 2-way, and a clear step up from the original CBM-170 SE this replaces. 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. High-frequency directivity narrows substantially above 10kHz, typical for a small dome tweeter, so the top octave will sound more reserved off-axis than on-axis. Bass rolls off as expected for a compact 2-way monitor: -3dB around 70Hz and -10dB around 50Hz, so a subwoofer is needed for full-range use. This data comes from the manufacturer’s own Klippel measurements rather than an independent third-party review, so there’s no outside verification of channel matching, distortion, or unit-to-unit consistency.
What the Polk Signature Elite ES20 offers: A full-size, efficient 6.5-inch bookshelf pair with unusually deep bass for the price. ASR measured 41Hz estimated in-room extension, a well-damped Q of 0.66, broad horizontal coverage to roughly +/-60 degrees and a 5.54 preference score with a subwoofer. Watch for: Predicted in-room smoothness of 0.238 and directivity-index consistency of 3.81 are average rather than class-leading. The deep cabinet needs substantial shelf or stand space, and its Power Port still requires rear clearance.
Buy the Ascend CBM-170 SE2 if sound quality is the priority over the price, or the Polk Signature Elite ES20 if the price is the priority over sound quality.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| Ascend CBM-170 SE2 | Polk Signature Elite ES20 | |
|---|---|---|
| Price | $468 per pair | $359 per pair |
| Ranked | #66 of 130 in Large Size Bookshelf Speakers | #69 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | - |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | - |
| 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 | 5.81 | 3.60 |
| Spinorama Preference Score with Perfect Sub | 8.17 | 5.54 |
| Enclosure | - | 2-way, Power Port bass-reflex |
| Country | - | United States (design) |
Related Speaker Comparisons
More worthwhile head-to-heads for Ascend CBM-170 SE2:
- Ascend CBM-170 SE2 vs Perlisten S4b
- Ascend CBM-170 SE2 vs KEF Reference 1 Meta
- Ascend CBM-170 SE2 vs GR-Research NX-Studio
- AsciLab C6B vs Ascend CBM-170 SE2
- Ascend CBM-170 SE2 vs Audio First Cadentia 3
Prices on this page were last checked September 16, 2026 at 12:41 AM 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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
Ascend CBM-170 SE2: $468 per pair Ascend Acoustics eBay
Pros: On-axis response is impressively flat from about 100Hz to 2kHz, staying within roughly ±1dB, with a clean, gradual bass rolloff below that. The directivity index rises smoothly and predictably through the crossover region, and the estimated in-room response shows a smooth, consistent downward tilt from 100Hz to 10kHz with no major discontinuities - close to the ideal in-room target shape. Measured sensitivity of 86.8dB nearly matches Ascend’s 87dB spec. The manufacturer’s own preference-score modeling comes out to 5.81 unequalized (rising to 8.17 with an ideal subwoofer, or 6.33/8.41 with EQ applied) - a strong result for a compact 2-way, and a clear step up from the original CBM-170 SE this replaces. Measured sensitivity of 86.8dB.
Cons: 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. High-frequency directivity narrows substantially above 10kHz, typical for a small dome tweeter, so the top octave will sound more reserved off-axis than on-axis. Bass rolls off as expected for a compact 2-way monitor: -3dB around 70Hz and -10dB around 50Hz, so a subwoofer is needed for full-range use. This data comes from the manufacturer’s own Klippel measurements rather than an independent third-party review, so there’s no outside verification of channel matching, distortion, or unit-to-unit consistency.
Full Ascend CBM-170 SE2 review and specifications →
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) |
| Dimensions | 12H x 9W x 9.5D in |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5" proprietary composite polygel cone woofer |
| Impedance | 8 ohms |
| Power Handling | 200W continuous, 400W peak |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) |
| Spinorama Preference Score | 5.81 |
| Spinorama Preference Score with Perfect Sub | 8.17 |
| Weight | 15 lbs (6.8 kg) each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Ascend CBM-170 SE2 vs Dynaudio Contour 20i
- Ascend CBM-170 SE2 vs Klipsch RP-600M II
- Ascend CBM-170 SE2 vs Dynaudio Emit 20
- Ascend CBM-170 SE2 vs Philharmonic BMR Monitor
- Ascend CBM-170 SE2 vs ELAC DBR62
- Ascend CBM-170 SE2 vs Mission LX-3 MKII
- Ascend CBM-170 SE2 vs GR-Research X-LS Encore
- Ascend CBM-170 SE2 vs Dynaudio Special Forty
- See all 44 comparisons
Polk Signature Elite ES20: $359 per pair B&H Photo Video eBay
Pros: A full-size, efficient 6.5-inch bookshelf pair with unusually deep bass for the price. ASR measured 41Hz estimated in-room extension, a well-damped Q of 0.66, broad horizontal coverage to roughly +/-60 degrees and a 5.54 preference score with a subwoofer.
Cons: Predicted in-room smoothness of 0.238 and directivity-index consistency of 3.81 are average rather than class-leading. The deep cabinet needs substantial shelf or stand space, and its Power Port still requires rear clearance.
Full Polk Signature Elite ES20 review and specifications →
| Country | United States (design) |
|---|---|
| Dimensions | 14.8H x 8.5W x 13.8D in |
| Drivers | 1" Terylene dome tweeter, 6.5" polypropylene woofer |
| Enclosure | 2-way, Power Port bass-reflex |
| Impedance | 4/8-ohm compatible |
| Sensitivity | 86dB |
| Spinorama Preference Score | 3.60 |
| Spinorama Preference Score with Perfect Sub | 5.54 |
| Weight | 17 lbs (7.7 kg) each |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Signature Elite ES20 vs Klipsch RP-600M II
- Polk Signature Elite ES20 vs Dynaudio Emit 20
- Polk Signature Elite ES20 vs Philharmonic BMR Monitor
- Polk Signature Elite ES20 vs Dynaudio Contour 20i
- Polk Signature Elite ES20 vs Mission LX-3 MKII
- Polk Signature Elite ES20 vs ELAC DBR62
- Polk Signature Elite ES20 vs GR-Research X-LS Encore
- Polk Signature Elite ES20 vs Dynaudio Special Forty
- See all 44 comparisons