Short answer: the Polk Monitor XT20. It ranks #90 of 131 bookshelf speakers by sound quality, rated 3.4/5, at $279; the GR Research Klipsch RP-600M Upgrade ranks #100, rated 3.2/5, at $279. With prices this close, go by the sound-quality ranking rather than the cost.
What the Polk Monitor XT20 does well: Two-way bookshelf design with a 1” tweeter and 6.5” woofer, part of Polk’s budget-friendly XT lineup (spanning roughly $200-700 across the series). The catch: Notably bright treble, elevated roughly 1-5dB above the midrange depending on frequency - a characteristic shared across the whole Polk XT lineup, requiring either EQ or toe-out to tame.
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 tradeoff: 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 Polk Monitor XT20. It is rated higher for sound quality than the GR Research Klipsch RP-600M Upgrade at the same price, so only choose the other one for a particular feature it does better.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| Polk Monitor XT20 | GR Research Klipsch RP-600M Upgrade | |
|---|---|---|
| Price | $279.00 per pair | $279 per pair |
| Ranked | #90 of 131 in Large Size Bookshelf Speakers | #100 of 131 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 43.4Hz (derived, log-interpolated between spinorama.org -9dB/-12dB points) | 40.0Hz (measured, spinorama.org ASR data) |
| Bass Extension (-3dB) | 64.5Hz (measured, Erin’s Audio Corner) | 68.8Hz (measured, spinorama.org ASR data) |
| Dimensions | 13”H x 7.5”W x 11”D (330.2 x 190.5 x 279.4 mm) | 15.7”H x 8”W x 11.9”D (398.8 x 203.2 x 302.3 mm) |
| Impedance | 8 ohms nominal (measured, Erin’s Audio Corner) | - |
| Sensitivity | 86dB (measured by Erin’s Audio Corner; 87dB manufacturer specified) | 86.7dB (measured, Audio Science Review) |
| Drivers | 6.5” bilaminate paper cone woofer, 1” Terylene dome tweeter | 6.5” Cerametallic cone woofer, 1” titanium LTS vented tweeter with Tractrix horn (stock Klipsch RP-600M drivers) |
| Weight | 11.9 lbs (5.4 kg) each | 16.1 lbs (7.3 kg) each |
| Woofer Cabinet | ported | ported |
| Spinorama Preference Score | 4.71 | 5.11 |
| Spinorama Preference Score with Perfect Sub | 7.07 | 7.06 |
| DIY Kit | No | Yes |
Related Speaker Comparisons
How Polk Monitor XT20 compares with other leading options:
- GR-Research NX-Studio vs Polk Monitor XT20
- AsciLab C6B vs Polk Monitor XT20
- Polk Monitor XT20 vs KEF R3 Meta
- Polk Monitor XT20 vs KEF Q Concerto Meta
- KEF R3 vs Polk Monitor XT20
Prices on this page were last checked September 26, 2026 at 11:14 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
Polk Monitor XT20: $279.00 per pair Amazon Crutchfield eBay
Pros: Two-way bookshelf design with a 1” tweeter and 6.5” woofer, part of Polk’s budget-friendly XT lineup (spanning roughly $200-700 across the series). Measures more linear and has fewer/smaller cabinet resonances than its smaller sibling, the XT15, making it - by the reviewer’s own assessment - probably the better of the two based on data alone. Reasonably good bass output for the price and size, with an F3 of 63Hz. Horizontal radiation of about ±50° gives a respectable, enjoyable soundstage width. Takes well to EQ correction - the early-reflections directivity trend is decently linear, meaning tonal adjustments can meaningfully improve the sound. Provides usable, respectable volume when paired with a subwoofer crossover, even though it isn’t intended to play extremely loud on its own. Measured bass extension of 64.5Hz (-3dB), with a measured sensitivity of 86dB.
Cons: Notably bright treble, elevated roughly 1-5dB above the midrange depending on frequency - a characteristic shared across the whole Polk XT lineup, requiring either EQ or toe-out to tame. Small resonances appear around 300Hz and 800Hz, with some of that energy leaking from the port area. Vertical listening window is narrow - best kept close to the tweeter axis, with only a couple of degrees of tolerance above or below before the sound changes. Still needs a subwoofer for real low-end extension despite the decent F3. Overall linearity isn’t state-of-the-art flat, and while the reviewer found it pleasant, some artificial brightness remains even after basic EQ correction in the crossover region.
Full Polk Monitor XT20 review and specifications →
| Bass Extension (-10dB) | 43.4Hz (derived, log-interpolated between spinorama.org -9dB/-12dB points) |
|---|---|
| Bass Extension (-3dB) | 64.5Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 13”H x 7.5”W x 11”D (330.2 x 190.5 x 279.4 mm) |
| Drivers | 6.5” bilaminate paper cone woofer, 1” Terylene dome tweeter |
| Impedance | 8 ohms nominal (measured, Erin’s Audio Corner) |
| Sensitivity | 86dB (measured by Erin’s Audio Corner; 87dB manufacturer specified) |
| Spinorama Preference Score | 4.71 |
| Spinorama Preference Score with Perfect Sub | 7.07 |
| Weight | 11.9 lbs (5.4 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: Polk’s new budget XT Speakers. Reviewed! More from Erin’s Audio Corner →
- Erin’s Audio Corner Website Polk Monitor XT20
- Erin’s Audio Corner: 10 Great (and Terrible) Speakers Under $300!
- Erin’s Audio Corner: Budget Stereo Systems You Will Love
- Erin’s Audio Corner Measurements (spinorama.org)
- Head-to-Head Comparisons
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- See all 42 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