Short answer: the Monoprice Monolith 16 THX Ultra for better sound quality, the SVS SB-4000 for the lower price. The Monoprice Monolith 16 THX Ultra ranks #18 of 110 subwoofers at $2300. The SVS SB-4000 ranks #63 at $1800, $500 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 SVS SB-4000 offers: Independent CEA-2010 testing records 98.5 dB at 20 Hz and 120.1 dB (avg of 3/4 bands) through 40-80 Hz. The sealed enclosure with 13.5” (343mm) driver delivers formidable upper-bass output for movie effects and music. 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 464.8H x 452.1W x 472.4D mm cabinet and 46.4 kg mass still require deliberate placement and calibration.
Buy the Monoprice Monolith 16 THX Ultra if sound quality is the priority over the price, or the SVS SB-4000 if the price is the priority over sound quality.
Looking for alternatives? See the complete Subwoofers rankings.
Specifications Side By Side
| Monoprice Monolith 16 THX Ultra | SVS SB-4000 | |
|---|---|---|
| Price | $2,300 | $1,800 |
| Ranked | #18 of 110 in Large Home Subwoofers (Over 75 lbs) | #63 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | sealed |
| Output SPL at 15 Hz | 107.3 dB | - |
| Output SPL at 20 Hz | 118.4 dB | 98.5 dB |
| Output SPL at 25 Hz | 123.3 dB | 101.3 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 108.1 dB |
| Output SPL at 40 Hz | 126.3 dB | 116.1 dB |
| Output SPL at 50 Hz | 126.5 dB | 121.1 dB |
| Output SPL at 63 Hz | 126.6 dB | 123.0 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 | - |
| CEA-2010-A Average (40-80Hz) | 126.5 dB | 120.1 dB (avg of 3/4 bands) |
| Dimensions | 25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm) | 18.3"H x 17.8"W x 18.6"D (464.8 x 452.1 x 472.4 mm) |
| Weight | 171.5 lbs (77.8 kg) | 102.3 lbs (46.4 kg) |
| Warranty | 5 | 5 |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Brian Kahn |
| Drivers | 16" (406mm) driver | 13.5" (343mm) driver |
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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 Reaction Audio PV-15X
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SVS SB-4000: $1,800 eBay
Pros: Independent CEA-2010 testing records 98.5 dB at 20 Hz and 120.1 dB (avg of 3/4 bands) through 40-80 Hz. The sealed enclosure with 13.5” (343mm) driver delivers formidable upper-bass output for movie effects and music.
Cons: 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 464.8H x 452.1W x 472.4D mm cabinet and 46.4 kg mass still require deliberate placement and calibration.
Full SVS SB-4000 review and specifications →
| CEA-2010-A Average (40-80Hz) | 120.1 dB (avg of 3/4 bands) |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 18.3"H x 17.8"W x 18.6"D (464.8 x 452.1 x 472.4 mm) |
| Drivers | 13.5" (343mm) driver |
| Enclosure | sealed |
| Measurement Source | Brian Kahn |
| Output SPL at 20 Hz | 98.5 dB |
| Output SPL at 25 Hz | 101.3 dB |
| Output SPL at 31.5 Hz | 108.1 dB |
| Output SPL at 40 Hz | 116.1 dB |
| Output SPL at 50 Hz | 121.1 dB |
| Output SPL at 63 Hz | 123.0 dB |
| Warranty | 5 |
| Weight | 102.3 lbs (46.4 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Brian Kahn; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons