Short answer: the HSU Research ULS-15 MK2 for the higher ranking, the Klipsch R-121SW for the lower price. The HSU Research ULS-15 MK2 ranks #3 of 137 subwoofers at $1035. The Klipsch R-121SW ranks #77 at $279, $756 cheaper.
What the HSU Research ULS-15 MK2 gets right: Sealed design delivers tight, accurate bass with low bloat.
On the Klipsch R-121SW side: 12-inch spun-copper driver with 200W RMS delivers controlled, musical bass with minimal distortion.
Buy the HSU Research ULS-15 MK2 if the ranking matters more than the price. Buy the Klipsch R-121SW if the price matters more than the ranking.
Specifications Side By Side
| HSU Research ULS-15 MK2 | Klipsch R-121SW | |
|---|---|---|
| Price | $1,035 | $279.00 |
| Ranked | #3 of 137 in Medium Powered Home Subwoofers (30-75 lbs) | #77 of 137 in Medium Powered Home Subwoofers (30-75 lbs) |
| Enclosure | sealed | ported, rear |
| Output SPL at 12.5 Hz | 93.7 dB | - |
| Output SPL at 15 Hz | 98.0 dB | 90.7 dB |
| Output SPL at 20 Hz | 102.4 dB | 96.0 dB |
| Output SPL at 25 Hz | 107.7 dB | 98.4 dB |
| Output SPL at 31.5 Hz | 113.4 dB | 102.3 dB |
| Output SPL at 40 Hz | 118.3 dB | 108.2 dB |
| Output SPL at 50 Hz | 120.8 dB | 112.4 dB |
| Output SPL at 63 Hz | 121.2 dB | 112.9 dB |
| Output SPL at 80 Hz | 121.1 dB | 111.3 dB |
| Output SPL at 100 Hz | 120.7 dB | 109.9 dB |
| Output SPL at 125 Hz | 120.7 dB | 108.3 dB |
| CEA-2010-A Average (40-80Hz) | 120.3 dB | 111.2 dB |
| Dimensions | 19.0"H x 18.0"W x 19.5"D (482.6 x 457.2 x 495.3 mm) | 16.6"H x 16.0"W x 19.7"D (421.6 x 406.4 x 500.4 mm) |
| Weight | 65 lbs / 29.5 kg | 35.1 lbs / 15.9 kg |
| Warranty | 7/2(+3) | 5/2 |
| Cabinet Color | black, wood | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Audioholics |
| Frequency Response | 20-200Hz, ±1dB | 28-120Hz |
| Power Output (Watts) | 600W RMS / 2000W peak | 200W RMS |
| Crossover | 30-90Hz adjustable | - |
| Phase Control | 0°-180° | - |
| Features | Q control, sealed subwoofer, EQ1/EQ2 modes | - |
| Drivers | 15" (381mm) driver | 12" (305mm) driver |
The Two Speakers In Full
HSU Research ULS-15 MK2: $1,035
Pros: Sealed design delivers tight, accurate bass with low bloat. 600W BASH amplifier. 30% less expensive and 20 lbs lighter than predecessor. Easy integration with Q and EQ controls. Great value in the 15” sub market at under $850 shipped.
Notes: Price includes shipping
| CEA-2010-A Average (40-80Hz) | 120.3 dB |
|---|---|
| Cabinet Color | black, wood |
| Country | United States |
| Crossover | 30-90Hz adjustable |
| Dimensions | 19.0"H x 18.0"W x 19.5"D (482.6 x 457.2 x 495.3 mm) |
| Drivers | 15" (381mm) driver |
| Enclosure | sealed |
| Features | Q control, sealed subwoofer, EQ1/EQ2 modes |
| Frequency Response | 20-200Hz, ±1dB |
| Measurement Source | Audioholics |
| Output SPL at 12.5 Hz | 93.7 dB |
| Output SPL at 15 Hz | 98.0 dB |
| Output SPL at 20 Hz | 102.4 dB |
| Output SPL at 25 Hz | 107.7 dB |
| Output SPL at 31.5 Hz | 113.4 dB |
| Output SPL at 40 Hz | 118.3 dB |
| Output SPL at 50 Hz | 120.8 dB |
| Output SPL at 63 Hz | 121.2 dB |
| Output SPL at 80 Hz | 121.1 dB |
| Output SPL at 100 Hz | 120.7 dB |
| Output SPL at 125 Hz | 120.7 dB |
| Phase Control | 0°-180° |
| Power Output (Watts) | 600W RMS / 2000W peak |
| Warranty | 7/2(+3) |
| Weight | 65 lbs / 29.5 kg |
- Head-to-Head Comparisons
- HSU Research ULS-15 MK2 vs MartinLogan Dynamo 1600X
- HSU Research ULS-15 MK2 vs Power Sound Audio (PSA) XV15
- HSU Research ULS-15 MK2 vs JTR Speakers Captivator 212PRO
- HSU Research ULS-15 MK2 vs Paradigm Defiance X12
- HSU Research ULS-15 MK2 vs Monoprice SW-15
- HSU Research ULS-15 MK2 vs SVS SB-3000
- HSU Research ULS-15 MK2 vs SVS PB-1000 PRO
- HSU Research ULS-15 MK2 vs Monoprice SW-12
- See all 14 comparisons
- Links
Klipsch R-121SW: $279.00 Amazon
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.
| CEA-2010-A Average (40-80Hz) | 111.2 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 16.6"H x 16.0"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 |
| Power Output (Watts) | 200W RMS |
| Warranty | 5/2 |
| Weight | 35.1 lbs / 15.9 kg |
- Head-to-Head Comparisons
- Klipsch R-121SW vs SVS SB-2000
- Klipsch R-121SW vs Monoprice Monolith M-10 V2
- Klipsch R-121SW vs RSL (Rogersound Labs) Speedwoofer 10S MKII
- Klipsch R-121SW vs Rythmik F12
- Klipsch R-121SW vs Monoprice SSW-10
- Klipsch R-121SW vs Monoprice SW-12
- Klipsch R-121SW vs SVS PB-1000 PRO
- Klipsch R-121SW vs Kef KC62
- See all 14 comparisons
- Links
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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.