Short answer: the Ascend CBM-170 SE2. It ranks #66 of 131 bookshelf speakers by sound quality, rated 3.8/5, at $468; the Polk Reserve R100 ranks #93, rated 3.4/5, and costs $699, so there is little reason to consider the other one.
What the Ascend CBM-170 SE2 does well: On-axis response is impressively flat from about 100Hz to 2kHz, staying within roughly ±1dB, with a clean, gradual bass rolloff below that. The tradeoff: 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 case for the Polk Reserve R100: Compact cabinet, unusually useful bass for its size and well-controlled woofer breakup. Watch for: Erin measured only about 85dB sensitivity and the impedance reaches 3.6 ohms, so it is neither efficient nor an entirely benign AVR load.
Buy the Ascend CBM-170 SE2. It is rated higher for sound quality than the Polk Reserve R100 and costs less, which makes it the one to get unless you need something the other one does better.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Ascend CBM-170 SE2 | Polk Reserve R100 | |
|---|---|---|
| Price | $468 per pair | $699.00 per pair |
| Ranked | #66 of 131 in Large Size Bookshelf Speakers | #93 of 131 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | 68Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | 49Hz (measured, Erin’s Audio Corner) |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) | 85dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5” proprietary composite polygel cone woofer | 1” Pinnacle ring-radiator tweeter; 5.25” Turbine Cone midwoofer |
| Dimensions | 12H x 9W x 9.5D in | 12.8”H x 6.5”W x 10.2”D |
| Weight | 15 lbs (6.8 kg) each | 12.1 lbs (5.5 kg) each |
| Impedance | 8 ohms | 3.6 ohms minimum (measured, Erin’s Audio Corner) |
| Power Handling | 200W continuous, 400W peak | - |
| Woofer Cabinet | ported, rear | ported, rear X-Port |
| Spinorama Preference Score | 6.30 | 5.46 |
| Spinorama Preference Score with Perfect Sub | 8.66 | 7.93 |
| DIY Kit | No | No |
Related Speaker Comparisons
How Ascend CBM-170 SE2 compares with other leading options:
- 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 26, 2026 at 11:14 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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The Two Speakers In Full
Ascend CBM-170 SE2: $468 per pair Ascend Acoustics eBay
Older model: the Ascend CBM-170 SE (rated 2.1/5).
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 6.30 unequalized (rising to 8.66 with an ideal subwoofer, or 6.79/8.86 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) |
| DIY Kit | No |
| 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 | 6.30 |
| Spinorama Preference Score with Perfect Sub | 8.66 |
| Weight | 15 lbs (6.8 kg) each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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Polk Reserve R100: $699.00 per pair Amazon Polk Audio eBay
Pros: Compact cabinet, unusually useful bass for its size and well-controlled woofer breakup. Erin measured F3/F10 points of 68Hz/49Hz, and the X-Port vent avoids much of the chuffing and pipe resonance common to budget rear ports. The 5.25-inch Turbine Cone woofer and 1-inch Pinnacle ring-radiator tweeter produce good detail at moderate levels, while listening roughly 20° off-axis reduces part of the elevated top octave. Measured bass extension of 68Hz (-3dB), with a measured sensitivity of 85dB.
Cons: Erin measured only about 85dB sensitivity and the impedance reaches 3.6 ohms, so it is neither efficient nor an entirely benign AVR load. The treble runs roughly 3dB above the midrange and becomes aggressive above about 85dB SPL. A directivity discontinuity through the woofer/tweeter crossover means EQ cannot fully repair the power response, and a 400Hz impedance feature plus 500Hz-1kHz response irregularity suggests a cabinet or system resonance. Substantial low-frequency compression at higher playback levels limits clean dynamics.
Full Polk Reserve R100 review and specifications →
| Bass Extension (-10dB) | 49Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 68Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 12.8”H x 6.5”W x 10.2”D |
| Drivers | 1” Pinnacle ring-radiator tweeter; 5.25” Turbine Cone midwoofer |
| Impedance | 3.6 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 85dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 5.46 |
| Spinorama Preference Score with Perfect Sub | 7.93 |
| Weight | 12.1 lbs (5.5 kg) each |
| Woofer Cabinet | ported, rear X-Port |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Reserve R100 vs Focal Aria 906
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