Short answer: the KEF R3 on measured sound quality, the GR Research Klipsch RP-600M Upgrade on price. The KEF R3 ranks #15 of 131 bookshelf speakers, rated 4.5/5, at $2,200. The GR Research Klipsch RP-600M Upgrade ranks #100, rated 3.2/5, at $279, $1,921 cheaper.
What the KEF R3 does well: True three-way stand-mount with a 6.5-inch woofer below KEF’s 5-inch Uni-Q midrange/1-inch tweeter. Watch for: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover.
Why pick 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. Watch for: 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 KEF R3 if sound quality is the priority over the price, or the GR Research Klipsch RP-600M Upgrade if the price is the priority over sound quality.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| KEF R3 | GR Research Klipsch RP-600M Upgrade | |
|---|---|---|
| Price | $2,200 per pair | $279 per pair |
| Ranked | #15 of 131 in Large Size Bookshelf Speakers | #100 of 131 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) | 68.8Hz (measured, spinorama.org ASR data) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | 40.0Hz (measured, spinorama.org ASR data) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) | 86.7dB (measured, Audio Science Review) |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier | - |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn (stock Klipsch RP-600M drivers) |
| Dimensions | 16.6”H x 7.9”W x 13.2”D | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) |
| Woofer Cabinet | ported, rear Flexible Port | ported |
| Weight | 29.9 lbs (13.55 kg) each | 16.1 lbs (7.3 kg) each |
| Spinorama Preference Score | 6.2 (spinorama.org) | 5.11 |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) | 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
KEF R3: $2,200 per pair Amazon eBay
Pros: True three-way stand-mount with a 6.5-inch woofer below KEF’s 5-inch Uni-Q midrange/1-inch tweeter. Erin measured approximately 86-87dB/2.83V/1m sensitivity, exceptionally low sub-1% distortion at 86dB and orderly directivity in both planes. The coaxial geometry maintains image stability across seats, while Flexible Port Technology avoids the strong midrange port resonance common to rear-vented competitors. A 110W Parasound drove it successfully in Erin’s listening. Measured bass extension of 35.2Hz (-10dB), with a measured sensitivity of 87dB.
Cons: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover. Narrow high-frequency features and natural Uni-Q narrowing toward the top octave make toe angle audible, although off-axis tracking remains smooth. Sensitivity is moderate, the cabinet weighs almost 30 lb, and this original R3 lacks the Meta successor’s MAT absorber.
Full KEF R3 review and specifications →
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) |
| DIY Kit | No |
| Dimensions | 16.6”H x 7.9”W x 13.2”D |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 6.2 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) |
| Weight | 29.9 lbs (13.55 kg) each |
| Woofer Cabinet | ported, rear Flexible Port |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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
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- GR Research Klipsch RP-600M Upgrade vs Klipsch RP-600M II
- GR Research Klipsch RP-600M Upgrade vs ELAC Debut 3.0 DB63
- GR Research Klipsch RP-600M Upgrade vs KEF Q Concerto Meta
- GR Research Klipsch RP-600M Upgrade vs KEF R3 Meta