Short answer: the Monoprice Monolith 16 THX Ultra for better sound quality, the Monoprice Monolith M-212 for the lower price. The Monoprice Monolith 16 THX Ultra ranks #18 of 110 subwoofers at $2300. The Monoprice Monolith M-212 ranks #61 at $1620, $680 cheaper.
What the Monoprice Monolith 16 THX Ultra offers: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked above it. Watch for: Heavy at 78 kg and ported design can interact with room acoustics.
What the Monoprice Monolith M-212 offers: Published CEA-2010 specifications list 110.3 dB at 20 Hz and 120.4 dB through 40-80 Hz. The ported, front enclosure with 2x 12” (305mm) drivers has the headroom for demanding film bass in a large room. Watch for: The 924.6H x 449.6W x 599.4D mm cabinet and 79.0 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.
Buy the Monoprice Monolith 16 THX Ultra if sound quality matters more than the price. Buy the Monoprice Monolith M-212 if the price matters more than sound quality.
Want more options? Browse the full Subwoofers rankings.
Specifications Side By Side
| Monoprice Monolith 16 THX Ultra | Monoprice Monolith M-212 | |
|---|---|---|
| Price | $2,300 | $1,620 |
| Ranked | #18 of 110 in Large Home Subwoofers (Over 75 lbs) | #61 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Output SPL at 15 Hz | 107.3 dB | 104.2 dB |
| Output SPL at 20 Hz | 118.4 dB | 110.3 dB |
| Output SPL at 25 Hz | 123.3 dB | 114.5 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 116.9 dB |
| Output SPL at 40 Hz | 126.3 dB | 119.7 dB |
| Output SPL at 50 Hz | 126.5 dB | 119.8 dB |
| Output SPL at 63 Hz | 126.6 dB | 120.3 dB |
| Output SPL at 80 Hz | 126.8 dB | 121.7 dB |
| Output SPL at 100 Hz | 127.2 dB | 121.5 dB |
| Output SPL at 125 Hz | 127.6 dB | 122.3 dB |
| CEA-2010-A Average (40-80Hz) | 126.5 dB | 120.4 dB |
| Dimensions | 25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm) | 36.4"H x 17.7"W x 23.6"D (924.6 x 449.6 x 599.4 mm) |
| Weight | 171.5 lbs (77.8 kg) | 174.2 lbs (79.0 kg) |
| Warranty | 5 | 5 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Manufacturer |
| Drivers | 16" (406mm) driver | 2x 12" (305mm) drivers |
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Prices on this page were last checked September 16, 2026 at 12:41 AM 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
Monoprice Monolith 16 THX Ultra: $2,300 eBay
Pros: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked above it.
Cons: Heavy at 78 kg and ported design can interact with room acoustics.
Notes: Product # 42031
Full Monoprice Monolith 16 THX Ultra review and specifications →
| CEA-2010-A Average (40-80Hz) | 126.5 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm) |
| Drivers | 16" (406mm) driver |
| Enclosure | ported, front |
| Measurement Source | Audioholics |
| Output SPL at 15 Hz | 107.3 dB |
| Output SPL at 20 Hz | 118.4 dB |
| Output SPL at 25 Hz | 123.3 dB |
| Output SPL at 31.5 Hz | 125.1 dB |
| Output SPL at 40 Hz | 126.3 dB |
| Output SPL at 50 Hz | 126.5 dB |
| Output SPL at 63 Hz | 126.6 dB |
| Output SPL at 80 Hz | 126.8 dB |
| Output SPL at 100 Hz | 127.2 dB |
| Output SPL at 125 Hz | 127.6 dB |
| Warranty | 5 |
| Weight | 171.5 lbs (77.8 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
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- Monoprice Monolith 16 THX Ultra vs Funk Audio Classic 18.0
- Monoprice Monolith 16 THX Ultra vs JTR Speakers Captivator 2400
- Monoprice Monolith 16 THX Ultra vs Reaction Audio PV-15X
- Monoprice Monolith 16 THX Ultra vs Harbinger V2218S
- Monoprice Monolith 16 THX Ultra vs Danley Sound Labs DTS10
- Monoprice Monolith 16 THX Ultra vs Rythmik FV25HP
- See all 88 comparisons
Monoprice Monolith M-212: $1,620 eBay
Pros: Published CEA-2010 specifications list 110.3 dB at 20 Hz and 120.4 dB through 40-80 Hz. The ported, front enclosure with 2x 12” (305mm) drivers has the headroom for demanding film bass in a large room.
Cons: The 924.6H x 449.6W x 599.4D mm cabinet and 79.0 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.
Notes: Product # 38544
Full Monoprice Monolith M-212 review and specifications →
| CEA-2010-A Average (40-80Hz) | 120.4 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 36.4"H x 17.7"W x 23.6"D (924.6 x 449.6 x 599.4 mm) |
| Drivers | 2x 12" (305mm) drivers |
| Enclosure | ported, front |
| Measurement Source | Manufacturer |
| Output SPL at 15 Hz | 104.2 dB |
| Output SPL at 20 Hz | 110.3 dB |
| Output SPL at 25 Hz | 114.5 dB |
| Output SPL at 31.5 Hz | 116.9 dB |
| Output SPL at 40 Hz | 119.7 dB |
| Output SPL at 50 Hz | 119.8 dB |
| Output SPL at 63 Hz | 120.3 dB |
| Output SPL at 80 Hz | 121.7 dB |
| Output SPL at 100 Hz | 121.5 dB |
| Output SPL at 125 Hz | 122.3 dB |
| Warranty | 5 |
| Weight | 174.2 lbs (79.0 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- These figures are manufacturer-specified rather than independently measured.
- Head-to-Head Comparisons