Short answer: both are discontinued, so this only matters if you are buying used. Used, the Monoprice Monolith 16 THX Ultra is the better pick: it ranks #19 of 143 subwoofers by sound quality (rated 4.4/5), against #128 (rated 3.8/5) for the Monoprice Monolith M-12 V2.
The Monoprice Monolith 16 THX Ultra is the better-sounding option. A THX Ultra certified 16 inch ported subwoofer with huge output for far less money than most rivals, now worth finding used. The tradeoff: Heavy at 172 lbs (78 kg) and ported design can interact with room acoustics.
Why pick the Monoprice Monolith M-12 V2: A good value THX certified 12 inch subwoofer with a port plug for sealed use and XLR inputs, now discontinued. Watch for: The cabinet is large at about 531mm tall, 655mm wide and 424mm deep, and weighs 98.3 lbs (44.6 kg).
Buy the Monoprice Monolith 16 THX Ultra only if you find one used in good condition; both are discontinued, and it is the better rated of the two.
Want more options? Browse the full Subwoofers rankings.
A THX Ultra certified 16 inch ported subwoofer with huge output for far less money than most rivals, now worth finding used.
A good value THX certified 12 inch subwoofer with a port plug for sealed use and XLR inputs, now discontinued.
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
| Monoprice Monolith 16 THX Ultra | Monoprice Monolith M-12 V2 | |
|---|---|---|
| Price | $2,300 Discontinued | $900 Discontinued |
| Ranked | #19 of 143 in Large Home Subwoofers (Over 75 lbs) | #128 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Output SPL at 15 Hz | 107.3 dB | 99.7 dB |
| Output SPL at 20 Hz | 118.4 dB | 108.3 dB |
| Output SPL at 25 Hz | 123.3 dB | 112.3 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 113.6 dB |
| Output SPL at 40 Hz | 126.3 dB | 114.2 dB |
| Output SPL at 50 Hz | 126.5 dB | 114.6 dB |
| Output SPL at 63 Hz | 126.6 dB | 115.0 dB |
| Output SPL at 80 Hz | 126.8 dB | 115.4 dB |
| Output SPL at 100 Hz | 127.2 dB | 115.9 dB |
| Output SPL at 125 Hz | 127.6 dB | 116.3 dB |
| CEA-2010-A Average (40-80Hz) | 126.5 dB | 114.8 dB |
| Dimensions | 25.6”H x 22”W x 28.1”D (650.2 x 558.8 x 713.7 mm) | 20.9”H x 25.8”W x 16.7”D (530.9 x 655.3 x 424.2 mm) |
| Weight | 171.5 lbs (77.8 kg) | 98.3 lbs (44.6 kg) |
| Warranty | 5 | 5 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Manufacturer |
| Drivers | 16” (406mm) driver | 12” (305mm) driver |
| Inputs | XLR, RCA, XLR out | XLR, RCA, XLR passthrough out |
| XLR Input | Yes | Yes |
| RCA Input | Yes | Yes |
| TRS Input | No | No |
| Optical Input | No | No |
| Coaxial Input | No | No |
| USB Input | No | No |
| HDMI Input | No | No |
| AES Input | No | No |
| Aux Input | No | No |
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