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 #64 of 222 bookshelf speakers, rated 4.1/5, at $1,688. The Klipsch RP-600M II ranks #123, rated 3.7/5, at $449.99, $1,238.01 cheaper.
The Klipsch RP-600M II is the more accurate, deeper-bass option. Bookshelf speakers with a large horn tweeter, wide soundstage, high efficiency and bi-amp ready terminals. Its measured preference score, a predictor of how neutral it sounds, is 5.64 against 4.53 for the Ascend Acoustics Sierra Duo V2 Ribbon. Its bass reaches about 70Hz before falling 3dB, against 79.1Hz for the Ascend Acoustics Sierra Duo V2 Ribbon. The catch: On-axis, the treble runs notably hot (even hotter than the original Klipsch RP-600M in some respects) and needs about 20° of toe-out or the grille installed to sound balanced.
The Ascend Acoustics Sierra Duo V2 Ribbon is the better-sounding pick. A compact dual woofer bookshelf speaker with a ribbon tweeter, very consistent dispersion, and flexible vertical or horizontal mounting. The catch: 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.
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.
Bookshelf speakers with a large horn tweeter, wide soundstage, high efficiency and bi-amp ready terminals.
A compact dual woofer bookshelf speaker with a ribbon tweeter, very consistent dispersion, and flexible vertical or horizontal mounting.
Prices on this page were last checked October 31, 2026 at 7:11 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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Specifications Side By Side
| Klipsch RP-600M II | Ascend Acoustics Sierra Duo V2 Ribbon | |
|---|---|---|
| Price | $449.99 per pair | $1,688 per pair |
| Ranked | #123 of 222 in Large Size Bookshelf Speakers | #64 of 222 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 | 5.64 | 4.53 |
| Spinorama Preference Score with Perfect Sub | 7.77 | 7.15 |
| DIY Kit | No | No |
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