Short answer: the Monoprice SW-15 for large-room output, the Klipsch R-121SW for a lighter, cheaper box. The SW-15 ranks #13 of 145 medium subwoofers at $374.99, and its 15-inch ported cabinet with 600W RMS (800W peak) earns a Large-room Bassaholic rating, though it is a budget-tier design that leans on ported room gain and offers limited dynamic headroom. The R-121SW costs $249 with a 12-inch spun-copper driver and 200W RMS.
On the Klipsch R-121SW side: 12-inch spun-copper driver with 200W RMS delivers controlled, musical bass with minimal distortion.
The case for the Monoprice SW-15: 15-inch ported with 600W RMS (800W peak) delivers Large-room Bassaholic rating. The catch: Budget-tier design, ported room gain dependency, 30 kg (66.1 lbs) mid-size, and limited dynamic headroom.
Buy the Monoprice SW-15. It is rated higher for sound quality, and saving $125.99 with the Klipsch R-121SW does not make up for the sound-quality gap.
Looking for alternatives? See the complete Subwoofers rankings.
Specifications Side By Side
| Klipsch R-121SW | Monoprice SW-15 | |
|---|---|---|
| Price | $249.00 | $374.99 |
| Ranked | #95 of 145 in Medium Home Subwoofers (30-75 lbs) | #13 of 145 in Medium Home Subwoofers (30-75 lbs) |
| Enclosure | ported, rear | ported, bottom |
| Output SPL at 15 Hz | 90.7 dB | 90.0 dB |
| Output SPL at 20 Hz | 96.0 dB | 101.2 dB |
| Output SPL at 25 Hz | 98.4 dB | 106.3 dB |
| Output SPL at 31.5 Hz | 102.3 dB | 111.2 dB |
| Output SPL at 40 Hz | 108.2 dB | 116.0 dB |
| Output SPL at 50 Hz | 112.4 dB | 120.2 dB |
| Output SPL at 63 Hz | 112.9 dB | 120.5 dB |
| Output SPL at 80 Hz | 111.3 dB | 119.5 dB |
| Output SPL at 100 Hz | 109.9 dB | - |
| Output SPL at 125 Hz | 108.3 dB | - |
| CEA-2010-A Average (40-80Hz) | 111.2 dB | 119.0 dB |
| Dimensions | 16.6"H x 16"W x 19.7"D (421.6 x 406.4 x 500.4 mm) | 18.1"H x 21"W x 22.7"D (459.7 x 533.4 x 576.6 mm) |
| Weight | 35.1 lbs (15.9 kg) | 66.1 lbs (30.0 kg) |
| Warranty | 5/2 | 1 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Audioholics |
| Amplifier Power | 200W RMS | 600W RMS / 800W peak |
| Frequency Response | 28-120Hz | 30-150Hz (-10dB) |
| Drivers | 12" (305mm) driver | 15" (381mm) driver |
| Crossover Frequency | - | 40-150Hz, 18dB/octave |
| Phase Control | - | 0° or 180° |
| Inputs | - | Stereo line level and speaker level |
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Prices on this page were last checked September 23, 2026 at 11:24 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 R-121SW: $249.00 Amazon eBay
Pros: 12-inch spun-copper driver with 200W RMS delivers controlled, musical bass with minimal distortion. Front-firing design maximizes placement flexibility. Excellent value with exceptional bang-for-buck.
Full Klipsch R-121SW review and specifications →
| Amplifier Power | 200W RMS |
|---|---|
| CEA-2010-A Average (40-80Hz) | 111.2 dB |
| Cabinet Color | black |
| Country | United States |
| Dimensions | 16.6"H x 16"W x 19.7"D (421.6 x 406.4 x 500.4 mm) |
| Drivers | 12" (305mm) driver |
| Enclosure | ported, rear |
| Frequency Response | 28-120Hz |
| Measurement Source | Audioholics |
| Output SPL at 15 Hz | 90.7 dB |
| Output SPL at 20 Hz | 96.0 dB |
| Output SPL at 25 Hz | 98.4 dB |
| Output SPL at 31.5 Hz | 102.3 dB |
| Output SPL at 40 Hz | 108.2 dB |
| Output SPL at 50 Hz | 112.4 dB |
| Output SPL at 63 Hz | 112.9 dB |
| Output SPL at 80 Hz | 111.3 dB |
| Output SPL at 100 Hz | 109.9 dB |
| Output SPL at 125 Hz | 108.3 dB |
| Warranty | 5/2 |
| Weight | 35.1 lbs (15.9 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Audioholics; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Klipsch R-121SW vs RSL (Rogersound Labs) Speedwoofer 10S MKII
- Klipsch R-121SW vs Monoprice Monolith M-10 V2
- Klipsch R-121SW vs Monoprice SSW-10
- Klipsch R-121SW vs Kef KC62
- Klipsch R-121SW vs SVS PB-1000 PRO
- Klipsch R-121SW vs SVS SB-2000
- Klipsch R-121SW vs JBL HDI-1200P
- Klipsch R-121SW vs Power Sound Audio (PSA) XS15SE
- See all 17 comparisons
Monoprice SW-15: $374.99 Amazon eBay
Pros: 15-inch ported with 600W RMS (800W peak) delivers Large-room Bassaholic rating. Unrivaled mid-bass punch for $375. Strong output with clean control. Dual speaker-level inputs and 40-150Hz crossover for flexible hookup.
Cons: Budget-tier design, ported room gain dependency, 30 kg mid-size, and limited dynamic headroom.
Notes: Product # 41499
Full Monoprice SW-15 review and specifications →
| Amplifier Power | 600W RMS / 800W peak |
|---|---|
| CEA-2010-A Average (40-80Hz) | 119.0 dB |
| Cabinet Color | black |
| Country | United States |
| Crossover Frequency | 40-150Hz, 18dB/octave |
| Dimensions | 18.1"H x 21"W x 22.7"D (459.7 x 533.4 x 576.6 mm) |
| Drivers | 15" (381mm) driver |
| Enclosure | ported, bottom |
| Frequency Response | 30-150Hz (-10dB) |
| Inputs | Stereo line level and speaker level |
| Measurement Source | Audioholics |
| Output SPL at 15 Hz | 90.0 dB |
| Output SPL at 20 Hz | 101.2 dB |
| Output SPL at 25 Hz | 106.3 dB |
| Output SPL at 31.5 Hz | 111.2 dB |
| Output SPL at 40 Hz | 116.0 dB |
| Output SPL at 50 Hz | 120.2 dB |
| Output SPL at 63 Hz | 120.5 dB |
| Output SPL at 80 Hz | 119.5 dB |
| Phase Control | 0° or 180° |
| Warranty | 1 |
| Weight | 66.1 lbs (30.0 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Audioholics; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- Monoprice SW-15 vs Power Sound Audio (PSA) XV15SEICE-BASE
- Monoprice SW-15 vs SVS SB-3000
- Monoprice SW-15 vs Power Sound Audio (PSA) XS15
- Monoprice SW-15 vs Power Sound Audio (PSA) XV15-BASE
- Monoprice SW-15 vs Paradigm Defiance X12
- Monoprice SW-15 vs Power Sound Audio (PSA) XS15-BASE
- Monoprice SW-15 vs Power Sound Audio (PSA) XV15
- Monoprice SW-15 vs Klipsch SPL-120
- See all 109 comparisons