Short answer: the Monoprice Monolith M-215 for better sound quality, the RSL (Rogersound Labs) Speedwoofer 12S for the lower price. The Monoprice Monolith M-215 ranks #24 of 143 subwoofers, rated 4.4/5, at $2,999.99. The RSL (Rogersound Labs) Speedwoofer 12S ranks #131, rated 3.7/5, at $884.96, $2,115.03 cheaper.
What the RSL (Rogersound Labs) Speedwoofer 12S does well: An affordable rear ported 12 inch subwoofer with strong deep bass output for movies. The tradeoff: The 565.1H x 479.4W x 562.0D mm cabinet and 82 lbs (37.2 kg) mass make this a serious placement and moving commitment.
The Monoprice Monolith M-215 is the better-sounding choice. A dual 15 inch ported subwoofer with excellent output down to the lowest notes, a strong value for large home theaters. Watch for: The 1074.4H x 508.0W x 701.0D mm cabinet and 216.1 lbs (98.0 kg) mass make this a serious placement and moving commitment.
Buy the RSL (Rogersound Labs) Speedwoofer 12S if the price is the priority over sound quality, or the Monoprice Monolith M-215 if sound quality is the priority over the price.
Want more options? Browse the full Subwoofers rankings.
An affordable rear ported 12 inch subwoofer with strong deep bass output for movies.
A dual 15 inch ported subwoofer with excellent output down to the lowest notes, a strong value for large home theaters.
Prices on this page were last checked October 31, 2026 at 7:11 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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Specifications Side By Side
| RSL (Rogersound Labs) Speedwoofer 12S | Monoprice Monolith M-215 | |
|---|---|---|
| Price | $884.96 | $2999.99 |
| Ranked | #131 of 143 in Large Home Subwoofers (Over 75 lbs) | #24 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, rear | ported, front |
| Output SPL at 15 Hz | 104.4 dB | 113.1 dB |
| Output SPL at 20 Hz | 109.3 dB | 118.9 dB |
| Output SPL at 25 Hz | 110.9 dB | 122.6 dB |
| Output SPL at 31.5 Hz | 112.5 dB | 125.2 dB |
| Output SPL at 40 Hz | 113.4 dB | 126.4 dB |
| Output SPL at 50 Hz | 113.4 dB | 126.1 dB |
| Output SPL at 63 Hz | 113.0 dB | 125.6 dB |
| Output SPL at 80 Hz | 113.1 dB | 125.6 dB |
| Output SPL at 100 Hz | 112.2 dB | 125.7 dB |
| CEA-2010-A Average (40-80Hz) | 113.2 dB | 125.9 dB |
| Dimensions | 22.2”H x 18.9”W x 22.1”D (565.1 x 479.4 x 562.0 mm) | 42.3”H x 20”W x 27.6”D (1074.4 x 508.0 x 701.0 mm) |
| Weight | 82 lbs (37.2 kg) | 216.1 lbs (98.0 kg) |
| Cabinet Color | black, white | black |
| Country | United States | United States |
| Measurement Source | ErinsAudioCorner | Brent Butterworth |
| Drivers | 12” (305mm) driver | 2x 15” (381mm) drivers |
| Warranty | 5/3 | 5 |
| Output SPL at 12.5 Hz | - | 103.9 dB |
| Output SPL at 125 Hz | - | 126.3 dB |
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