Short answer: the Monoprice Monolith M-215. It ranks #24 of 143 subwoofers by sound quality (rated 4.4/5) at $2,999.99 and is still sold new; the BK Electronics Monolith-DF ranks #141 (rated 3.3/5) and is discontinued, so it is only an option used.
Why pick the BK Electronics Monolith-DF: A down ported 12 inch subwoofer with balanced XLR and RCA inputs at a low price, now discontinued. Watch for: Deep-bass output is more limited than the strong 40-80 Hz result suggests, so it is not the right choice when the lowest movie effects are the priority.
The Monoprice Monolith M-215 is the better-sounding pick. 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 Monoprice Monolith M-215. It is rated higher for sound quality; the BK Electronics Monolith-DF is no longer sold new.
Looking for alternatives? See the complete Subwoofers rankings.
A down ported 12 inch subwoofer with balanced XLR and RCA inputs at a low price, now discontinued.
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
| BK Electronics Monolith-DF | Monoprice Monolith M-215 | |
|---|---|---|
| Price | £406.95 Discontinued | $2999.99 |
| Ranked | #141 of 143 in Large Home Subwoofers (Over 75 lbs) | #24 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, bottom | ported, front |
| Output SPL at 15 Hz | 91.3 dB | 113.1 dB |
| Output SPL at 20 Hz | 102.0 dB | 118.9 dB |
| Output SPL at 25 Hz | 106.4 dB | 122.6 dB |
| Output SPL at 31.5 Hz | 108.3 dB | 125.2 dB |
| Output SPL at 40 Hz | 108.6 dB | 126.4 dB |
| Output SPL at 50 Hz | 108.7 dB | 126.1 dB |
| Output SPL at 63 Hz | 108.6 dB | 125.6 dB |
| Output SPL at 80 Hz | 107.7 dB | 125.6 dB |
| CEA-2010-A Average (40-80Hz) | 108.4 dB | 125.9 dB |
| Dimensions | 23.8”H x 21.3”W x 16.5”D (603.8 x 539.8 x 419.9 mm) | 42.3”H x 20”W x 27.6”D (1074.4 x 508.0 x 701.0 mm) |
| Weight | 103.2 lbs (46.8 kg) | 216.1 lbs (98.0 kg) |
| Warranty | 2 | 5 |
| Cabinet Color | black, wood | black |
| Country | United Kingdom | United States |
| Measurement Source | Ilkka Rissanen | Brent Butterworth |
| Drivers | 12” (305mm) driver with ported design | 2x 15” (381mm) drivers |
| Inputs | XLR (balanced), RCA (unbalanced) | - |
| XLR Input | Yes | - |
| RCA Input | Yes | - |
| TRS Input | No | - |
| Optical Input | No | - |
| Coaxial Input | No | - |
| USB Input | No | - |
| HDMI Input | No | - |
| AES Input | No | - |
| Aux Input | No | - |
| Output SPL at 12.5 Hz | - | 103.9 dB |
| Output SPL at 100 Hz | - | 125.7 dB |
| Output SPL at 125 Hz | - | 126.3 dB |
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