The GR Research Klipsch RP-600M Upgrade ranks #100 out of 131 total Large Size Bookshelf Speakers for sound quality. See all Passive Home rankings for every top pick.
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#100 GR Research Klipsch RP-600M Upgrade: $279 per pair GR Research eBay
Pros: GR Research’s replacement crossover fixes the stock Klipsch RP-600M’s biggest flaw, a deep response dip around the crossover, by using gentler first-order filters. Audio Science Review’s measurements show listening-window smoothness rising from 0.40 to 0.78 and the preference score from 3.66 to 5.11 (5.61 to 7.06 with an ideal subwoofer), with response within 3dB from 80Hz to 20kHz. Bass reaches 68.8Hz at -3dB and about 40Hz at -10dB, and the kit also cuts ringing around 800Hz. At $279 per pair it comes with all new crossover parts, No-Rez damping, wiring and connectors. Measured bass extension of 68.8Hz (-3dB), with a measured sensitivity of 86.7dB.
Cons: This is a DIY kit, not a finished speaker: you need a pair of the original Klipsch RP-600M, which is discontinued, and must rebuild both crossovers yourself. It does not fit the RP-600M II. Sensitivity drops about 1.5dB to 86.7dB, horizontal directivity narrows for a smaller sweet spot, and a 4.44 directivity-index deviation shows uneven off-axis sound. Average on-axis deviation of 0.49dB is rougher than the stock speaker’s 0.23dB, and the current RP-600M II scores higher (5.64) with no work at all.
How it compares: Just above it: Polk R200 - $520 more, 1.7Hz lower bass extension (-3dB). Just below it: JBL XPL-90 - $1019 more, 1.7Hz lower bass extension (-3dB).
| Bass Extension (-10dB) | 40.0Hz (measured, spinorama.org ASR data) |
|---|---|
| Bass Extension (-3dB) | 68.8Hz (measured, spinorama.org ASR data) |
| DIY Kit | Yes |
| Dimensions | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) |
| Drivers | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn (stock Klipsch RP-600M drivers) |
| Sensitivity | 86.7dB (measured, Audio Science Review) |
| Spinorama Preference Score | 5.11 |
| Spinorama Preference Score with Perfect Sub | 7.06 |
| Weight | 16.1 lbs (7.3 kg) each |
| Woofer Cabinet | ported |
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