Short answer: the Klipsch RP-600M II. Both are rated 3.7/5 for sound quality (#123 and #120 of 222 bookshelf speakers), and the Klipsch RP-600M II costs $449.99 against $3,400 for the Theory Audio sb25, and with sound quality even, the cheaper one is the better buy.
The Klipsch RP-600M II is the more accurate 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 4.33 for the Theory Audio sb25. Watch for: 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.
What the Theory Audio sb25 does well: Very slim surface-mount speakers with dual 5 inch woofers, wide dispersion and high output, made for custom installs. The catch: It requires a Theory controller-amplifier channel and model-specific DSP, making it much less straightforward than a normal passive speaker.
Buy the Klipsch RP-600M II. Both are rated the same for sound quality, and it costs $2,950.01 less than the Theory Audio sb25.
Want more options? Browse the full Passive Home rankings.
Bookshelf speakers with a large horn tweeter, wide soundstage, high efficiency and bi-amp ready terminals.
Very slim surface-mount speakers with dual 5 inch woofers, wide dispersion and high output, made for custom installs.
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Specifications Side By Side
| Klipsch RP-600M II | Theory Audio sb25 | |
|---|---|---|
| Price | $449.99 per pair | $3,400 per pair |
| Ranked | #123 of 222 in Large Size Bookshelf Speakers | #120 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 41Hz (measured, Erin’s Audio Corner) | 46Hz (manufacturer specified) |
| Bass Extension (-3dB) | 70Hz (measured, Erin’s Audio Corner) | 67.4Hz (measured, spinorama.org) |
| Dimensions | 15.7”H x 8”W x 12.5”D (398.8 x 203.2 x 317.5 mm) | 21.5H x 9.5W x 3.8D in |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin’s Audio Corner) | 4 ohms |
| Sensitivity | 86dB (measured, Erin’s Audio Corner) | 94dB (manufacturer specified, 2.83V/1m) |
| Drivers | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn | Dual 5-inch carbon-fiber woofers, 1.4-inch compression driver |
| Weight | 13 lbs (5.9 kg) each | 22.9 lbs (10.4 kg) each |
| Woofer Cabinet | ported | - |
| Spinorama Preference Score | 5.64 | 4.33 |
| Spinorama Preference Score with Perfect Sub | 7.77 | 6.99 |
| DIY Kit | No | No |
| Enclosure | - | Passive sealed surface/tabletop speaker |
| Frequency Response | - | 54Hz-23kHz (-6dB) |
| Coverage | - | 125 degrees conical |
| Power Handling | - | 200W AES, 800W peak |
| Maximum SPL | - | 123dB peak at 1m |
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