Short answer: the Ascend CBM-170 SE2. It ranks #57 of 105 bookshelf speakers by sound quality at $468; the Klipsch RP-600M II ranks #58 and costs $489.99, so there is not much of a tradeoff to weigh.
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 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.
On the Klipsch RP-600M II side: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. The catch: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced.
Buy the Ascend CBM-170 SE2. It ranks higher for sound quality than the Klipsch RP-600M II and costs less, so there is no real case for the other one.
Specifications Side By Side
| Ascend CBM-170 SE2 | Klipsch RP-600M II | |
|---|---|---|
| Price | $468 | $489.99 |
| Ranked | #57 of 105 in Large Size Bookshelf Speakers | #58 of 105 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | 70Hz (measured, manufacturer spinorama data) | 70Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 50Hz (measured, manufacturer spinorama data) | 41Hz (measured, Erin’s Audio Corner) |
| Sensitivity | 86.8dB (2.83V/1m, measured, manufacturer spinorama data; 87dB manufacturer specified) | 86dB (measured, Erin’s Audio Corner) |
| Drivers | 27mm custom SEAS soft dome tweeter, 6.5" proprietary composite polygel cone woofer | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn |
| Dimensions | 12H x 9W x 9.5D in | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) |
| Weight | 15 lbs / 6.8 kg each | 13 lbs / 5.9 kg each |
| Impedance | 8 ohms | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin’s Audio Corner) |
| Power Handling | 200W continuous, 400W peak | - |
| Woofer Cabinet | ported, rear | ported |
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The Two Speakers In Full
Ascend CBM-170 SE2: $468 Ascend Acoustics
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.
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) |
| Weight | 15 lbs / 6.8 kg each |
| Woofer Cabinet | ported, rear |
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- Links
- Reviews, Comparisons and Sound Samples
Klipsch RP-600M II: $489.99 Amazon
Pros: Redesigned waveguide extends flush to the baffle edge, reducing diffraction compared to the original RP-600M. Roughly 10-20° wider horizontal radiation than the original, giving more soundstage envelopment while retaining precise imaging. A major step up in overall tonal neutrality compared to the original RP-600M, largely eliminating that model’s midrange resonance issues. Unusually, sounds better with the grille on - the grille smooths out the elevated treble rather than degrading the sound, a rare trait among speakers the reviewer has tested. More refined back-panel hardware, including anodized binding posts and jumper cables for optional bi-amping. Responds well to EQ correction (verified using measurement software and a miniDSP), letting the on-axis response be made genuinely linear.
Cons: On-axis, the treble runs notably hot - even hotter than the original RP-600M in some respects - and needs about 20° of toe-out or the grille installed to sound balanced. Horizontal dispersion is very slightly less linear across angles than the original RP-600M, a minor trade-off for the wider overall radiation pattern. Klipsch’s marketed sensitivity (about 94.5dB) is, like the original, a half-space rating roughly 9dB above the anechoic reality (closer to 85-86dB). In-room bass rolls off around 60Hz in practice, and a 120Hz boost paired with a midrange scoop gives kick drums their “tambour” without real low-end weight - a subwoofer is still recommended. Vertical listening tolerance is limited to about ±10° from the tweeter axis. Toeing the speaker out for better on-axis tonality (rather than using the grille) introduces slightly more diffuse imaging from added sidewall reflections.
Full Klipsch RP-600M II review and specifications →
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) |
| Sensitivity | 86dB (measured, Erin's Audio Corner) |
| Weight | 13 lbs / 5.9 kg each |
| Woofer Cabinet | ported |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: The Truth about Klipsch’s “NEW” Sound. RP-600M Update.
- Erin’s Audio Corner Website Klipsch RP-600M II
- GR-Research: We Bought The “NEW” RP-600M II Is KLIPSCH Listening?!
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner Measurements (spinorama.org)
- Reddit Search for Klipsch RP-600M II Review
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