Short answer: the Ascend CBM-170 SE2. It ranks #66 of 130 bookshelf speakers by sound quality at $468; the ATC SCM19 ranks #119 and costs $3750, so there is little reason to consider the other one.
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 ATC SCM19 offers: Harmonic distortion at 96dB SPL/1m stays generally low across the range aside from the spike tied to the 700-800Hz resonance. Sealed (unported) cabinet avoids port noise and resonance, and the extremely dense, heavy-duty enclosure (17.8kg/39lb each) reflects ATC’s pro-audio build standards. Watch for: Some stored energy resonance around 500-700hz, 4dB bump around 700hz. Not recommended for the price. CEA2034 spinorama and predicted in-room response both show a very uneven overall balance - a broad accentuation from midrange to treble paired with too little bass - along with directivity error. At 96dB SPL/1m, harmonic distortion tied to the 500-700Hz resonance rises to a level the reviewer says “should not be there.”
Buy the Ascend CBM-170 SE2. It ranks higher for sound quality than the ATC SCM19 and costs less, which settles it without a real tradeoff to make.
If sound quality matters at all to you, skip the ATC SCM19. It ranks near the bottom of the 130 bookshelf speakers, so look higher up the list instead.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Ascend CBM-170 SE2 | ATC SCM19 | |
|---|---|---|
| Price | $468 per pair | $3750 per pair |
| Ranked | #66 of 130 in Large Size Bookshelf Speakers | #119 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | 60Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | 34Hz (measured, Audio Science Review) |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) | 85dB (measured, Audio Science Review) |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5" proprietary composite polygel cone woofer | 5.9" Super Linear Magnet cone woofer, 1" soft dome tweeter |
| Dimensions | 12H x 9W x 9.5D in | 17.2"H x 10.4"W x 11.8"D (436.9 x 264.2 x 299.7 mm) |
| Weight | 15 lbs (6.8 kg) each | 39.2 lbs (17.8 kg) each |
| Impedance | 8 ohms | 6 ohms |
| Power Handling | 200W continuous, 400W peak | - |
| Woofer Cabinet | ported, rear | sealed |
| Spinorama Preference Score | 5.81 | 3.79 |
| Spinorama Preference Score with Perfect Sub | 8.17 | 6.21 |
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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.
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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
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ATC SCM19: $3750 per pair Tmraudio eBay
Pros: Harmonic distortion at 96dB SPL/1m stays generally low across the range aside from the spike tied to the 700-800Hz resonance. Sealed (unported) cabinet avoids port noise and resonance, and the extremely dense, heavy-duty enclosure (17.8kg/39lb each) reflects ATC’s pro-audio build standards. Measured bass extension of 60Hz (-3dB), with a measured sensitivity of 85dB.
Cons: Some stored energy resonance around 500-700hz, 4dB bump around 700hz. Not recommended for the price. CEA2034 spinorama and predicted in-room response both show a very uneven overall balance - a broad accentuation from midrange to treble paired with too little bass - along with directivity error. At 96dB SPL/1m, harmonic distortion tied to the 500-700Hz resonance rises to a level the reviewer says “should not be there.”
Full ATC SCM19 review and specifications →
| Bass Extension (-10dB) | 34Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 60Hz (measured, Audio Science Review) |
| Dimensions | 17.2"H x 10.4"W x 11.8"D (436.9 x 264.2 x 299.7 mm) |
| Drivers | 5.9" Super Linear Magnet cone woofer, 1" soft dome tweeter |
| Impedance | 6 ohms |
| Sensitivity | 85dB (measured, Audio Science Review) |
| Spinorama Preference Score | 3.79 |
| Spinorama Preference Score with Perfect Sub | 6.21 |
| Weight | 39.2 lbs (17.8 kg) each |
| Woofer Cabinet | sealed |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons