Short answer: the Klipsch RP-600M II. It ranks #73 of 131 bookshelf speakers by sound quality, rated 3.7/5, at $449.99. The GR Research Klipsch RP-600M Upgrade ranks #100, rated 3.2/5, at $279, $170.99 cheaper, not enough of a saving to outweigh the sound-quality gap.
What the Klipsch RP-600M II does well: 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.
The case for the GR Research Klipsch RP-600M Upgrade: 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. The catch: 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.
Buy the Klipsch RP-600M II. It is rated higher for sound quality, and the $170.99 you would save on the GR Research Klipsch RP-600M Upgrade does not close the gap.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| Klipsch RP-600M II | GR Research Klipsch RP-600M Upgrade | |
|---|---|---|
| Price | $449.99 per pair | $279 per pair |
| Ranked | #73 of 131 in Large Size Bookshelf Speakers | #100 of 131 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 41Hz (measured, Erin’s Audio Corner) | 40.0Hz (measured, spinorama.org ASR data) |
| Bass Extension (-3dB) | 70Hz (measured, Erin’s Audio Corner) | 68.8Hz (measured, spinorama.org ASR data) |
| Dimensions | 15.7”H x 8”W x 12.5”D (398.8 x 203.2 x 317.5 mm) | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) |
| Impedance | 8 ohms nominal (3.5 ohms minimum above 80Hz, measured by Erin’s Audio Corner) | - |
| Sensitivity | 86dB (measured, Erin’s Audio Corner) | 86.7dB (measured, Audio Science Review) |
| Drivers | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn (stock Klipsch RP-600M drivers) |
| Weight | 13 lbs (5.9 kg) each | 16.1 lbs (7.3 kg) each |
| Woofer Cabinet | ported | ported |
| Spinorama Preference Score | 5.64 | 5.11 |
| Spinorama Preference Score with Perfect Sub | 7.77 | 7.06 |
| DIY Kit | No | Yes |
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Prices on this page were last checked September 30, 2026 at 2:57 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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The Two Speakers In Full
Klipsch RP-600M II: $449.99 per pair Amazon eBay
Older model: the Klipsch RP-600M (ranked lower, rated 2.9/5).
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) |
| DIY Kit | No |
| 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 | 5.64 |
| Spinorama Preference Score with Perfect Sub | 7.77 |
| 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
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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.
Full GR Research Klipsch RP-600M Upgrade review and specifications →
| 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 |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- GR Research Klipsch RP-600M Upgrade vs DIYSG HT-10
- GR Research Klipsch RP-600M Upgrade vs Polk Monitor XT20
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- GR Research Klipsch RP-600M Upgrade vs ELAC Debut 3.0 DB63
- GR Research Klipsch RP-600M Upgrade vs KEF R3
- GR Research Klipsch RP-600M Upgrade vs KEF Q Concerto Meta
- GR Research Klipsch RP-600M Upgrade vs KEF R3 Meta