Short answer: the Ascend Acoustics Sierra Duo V2 Ribbon if sound quality matters most, the Klipsch RP-600M II if price matters most. The Ascend Acoustics Sierra Duo V2 Ribbon ranks #52 of 130 bookshelf speakers at $1688. The Klipsch RP-600M II ranks #74 at $449.99, $1238.01 cheaper.
What the Klipsch RP-600M II offers: 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. Watch for: 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.
What the Ascend Acoustics Sierra Duo V2 Ribbon offers: High-quality manufacturer NFS data gives the RAAL version a low 2.09 sound-power directivity-index standard deviation, the most consistent dispersion of the two Duo V2 variants. Its preference score improves from 3.62 to 6.23 with a subwoofer, while the compact bamboo cabinet, dual front slots, and vertical or horizontal mounting options are unusually flexible. Watch for: Bass measures 79.1Hz at -3dB, 64.5Hz at -6dB, and 43.9Hz at -12dB, and the 0.645dB on-axis average absolute deviation trails the Titan version’s 0.585dB. The 0.410 normalized listening-window deviation and narrow horizontal dispersion when the MTM cabinet is placed horizontally make vertical orientation preferable; a subwoofer is strongly recommended.
Buy the Klipsch RP-600M II when the price outweighs sound quality for you, and the Ascend Acoustics Sierra Duo V2 Ribbon when sound quality outweighs the price instead.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| Klipsch RP-600M II | Ascend Acoustics Sierra Duo V2 Ribbon | |
|---|---|---|
| Price | $449.99 per pair | $1,688 per pair |
| Ranked | #74 of 130 in Large Size Bookshelf Speakers | #52 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 41Hz (measured, Erin's Audio Corner) | approximately 50Hz (measured, spinorama.org) |
| Bass Extension (-3dB) | 70Hz (measured, Erin's Audio Corner) | 79.1Hz (measured, spinorama.org) |
| Dimensions | 15.7"H x 8"W x 12.5"D (398.8 x 203.2 x 317.5 mm) | 16.25 x 5.75 x 6 in each |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin's Audio Corner) | 8 ohms nominal |
| Sensitivity | 86dB (measured, Erin's Audio Corner) | 86dB at 2.83V/1m anechoic |
| Drivers | 6.5" Cerametallic cone woofer, 1" titanium LTS vented tweeter with Tractrix horn | Two 4.5-inch glass-fiber woofers; custom RAAL true ribbon tweeter |
| Weight | 13 lbs (5.9 kg) each | 12.3 lbs (5.6 kg) each |
| Woofer Cabinet | ported | - |
| Spinorama Preference Score | 4.75 | 3.62 |
| Spinorama Preference Score with Perfect Sub | 6.88 | 6.23 |
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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
Klipsch RP-600M II: $449.99 per pair Amazon eBay
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. Measured bass extension of 70Hz (-3dB), with a measured sensitivity of 86dB.
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) |
| Spinorama Preference Score | 4.75 |
| Spinorama Preference Score with Perfect Sub | 6.88 |
| Weight | 13 lbs (5.9 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: The Truth about Klipsch’s “NEW” Sound. RP-600M Update. More from Erin’s Audio Corner →
- Erin’s Audio Corner Website Klipsch RP-600M II
- GR-Research: We Bought The "NEW" RP-600M II Is KLIPSCH Listening?! More from GR-Research →
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner Measurements (spinorama.org)
- Head-to-Head Comparisons
- Klipsch RP-600M II vs Dynaudio Emit 20
- Klipsch RP-600M II vs Aoshida Audio Musician Knight I V2
- Klipsch RP-600M II vs Philharmonic BMR Monitor
- Klipsch RP-600M II vs JBL 708i
- Klipsch RP-600M II vs JBL Studio 630
- Klipsch RP-600M II vs PS Audio Aspen FR5
- Klipsch RP-600M II vs Behringer B2030P
- Klipsch RP-600M II vs Theory Audio sb25
- See all 116 comparisons
Ascend Acoustics Sierra Duo V2 Ribbon: $1,688 per pair Ascend Acoustics eBay
Pros: High-quality manufacturer NFS data gives the RAAL version a low 2.09 sound-power directivity-index standard deviation, the most consistent dispersion of the two Duo V2 variants. Its preference score improves from 3.62 to 6.23 with a subwoofer, while the compact bamboo cabinet, dual front slots, and vertical or horizontal mounting options are unusually flexible. Measured bass extension of 79.1Hz (-3dB).
Cons: Bass measures 79.1Hz at -3dB, 64.5Hz at -6dB, and 43.9Hz at -12dB, and the 0.645dB on-axis average absolute deviation trails the Titan version’s 0.585dB. The 0.410 normalized listening-window deviation and narrow horizontal dispersion when the MTM cabinet is placed horizontally make vertical orientation preferable; a subwoofer is strongly recommended.
Full Ascend Acoustics Sierra Duo V2 Ribbon review and specifications →
| Bass Extension (-10dB) | approximately 50Hz (measured, spinorama.org) |
|---|---|
| Bass Extension (-3dB) | 79.1Hz (measured, spinorama.org) |
| Dimensions | 16.25 x 5.75 x 6 in each |
| Drivers | Two 4.5-inch glass-fiber woofers; custom RAAL true ribbon tweeter |
| Impedance | 8 ohms nominal |
| Sensitivity | 86dB at 2.83V/1m anechoic |
| Spinorama Preference Score | 3.62 |
| Spinorama Preference Score with Perfect Sub | 6.23 |
| Weight | 12.3 lbs (5.6 kg) each |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons