Short answer: both are discontinued, so this only matters if you are buying used. Used, the SVS PB-4000 is the better pick: it ranks #68 of 139 subwoofers by sound quality (rated 4.2/5), against #85 (rated 4.1/5) for the Monoprice Monolith M15-S. If you want one new, the SVS PB-5000 R-Evolution replaces the SVS PB-4000 and is rated 4.2/5 at $2,599.
Buy the SVS PB-4000 only if you find one used in good condition; both are discontinued, and it is the better rated of the two. For a new speaker, buy the SVS PB-5000 R-Evolution, which replaces the SVS PB-4000.
Want more options? Browse the full Subwoofers rankings.
Specifications Side By Side
| Monoprice Monolith M15-S | SVS PB-4000 | |
|---|---|---|
| Price | $999 Discontinued | $2,158.97 Discontinued |
| Ranked | #85 of 139 in Large Home Subwoofers (Over 75 lbs) | #68 of 139 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | sealed | ported, front |
| Output SPL at 15 Hz | 100.1 dB | 102.1 dB |
| Output SPL at 20 Hz | 105.6 dB | 115.3 dB |
| Output SPL at 25 Hz | 111.2 dB | 116.3 dB |
| Output SPL at 31.5 Hz | 115.2 dB | 117.8 dB |
| Output SPL at 40 Hz | 118.4 dB | 119.8 dB |
| Output SPL at 50 Hz | 119.3 dB | 121.7 dB |
| Output SPL at 63 Hz | 119.6 dB | 120.7 dB |
| Output SPL at 80 Hz | 118.9 dB | 119.2 dB |
| Output SPL at 100 Hz | 119.1 dB | 118.1 dB |
| Output SPL at 125 Hz | 118.9 dB | 117.5 dB |
| CEA-2010-A Average (40-80Hz) | 119.0 dB | 120.3 dB |
| Dimensions | 23.5”H x 16.7”W x 19.7”D (596.9 x 424.2 x 500.4 mm) | 23.4”H x 20.5”W x 27.7”D (594.4 x 520.7 x 703.6 mm) |
| Warranty | 5 | 5 |
| Country | United States | United States |
| Measurement Source | Manufacturer | Audioholics |
| Weight | 80 lbs (36.3 kg) | 153.2 lbs (69.5 kg) |
| Drivers | 15” (381mm) driver | 13.5” (343mm) driver with ported design |
| Cabinet Color | - | black |
| Inputs | - | XLR (balanced), RCA (LFE/stereo) |
| 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 |
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- JTR Speakers Orbit Shifter LFU vs SVS PB-4000
- Power Sound Audio (PSA) TRIAX vs SVS PB-4000
- JTR Speakers Captivator 4000ULF vs SVS PB-4000
- JTR Speakers Captivator S2 vs SVS PB-4000
Prices on this page were last checked October 7, 2026 at 9:25 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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The Two Speakers In Full
Monoprice Monolith M15-S: $999 Discontinued eBay
Same family: the Monoprice Monolith M10-S (smaller subwoofer, rated 3.4/5) and the Monoprice Monolith M12-S (smaller subwoofer, ranked lower, rated 3.7/5).
Pros: Published CEA-2010 specifications list 105.6 dB at 20 Hz and 119.0 dB through 40-80 Hz. The sealed enclosure with 15” (381mm) driver has the headroom for demanding film bass in a large room.
Cons: The 596.9H x 424.2W x 500.4D mm cabinet and 36.3 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks. Discontinued.
Notes: Product # 35141
Full Monoprice Monolith M15-S review and specifications →
| CEA-2010-A Average (40-80Hz) | 119.0 dB |
|---|---|
| Country | United States |
| Dimensions | 23.5”H x 16.7”W x 19.7”D (596.9 x 424.2 x 500.4 mm) |
| Drivers | 15” (381mm) driver |
| Enclosure | sealed |
| Measurement Source | Manufacturer |
| Output SPL at 15 Hz | 100.1 dB |
| Output SPL at 20 Hz | 105.6 dB |
| Output SPL at 25 Hz | 111.2 dB |
| Output SPL at 31.5 Hz | 115.2 dB |
| Output SPL at 40 Hz | 118.4 dB |
| Output SPL at 50 Hz | 119.3 dB |
| Output SPL at 63 Hz | 119.6 dB |
| Output SPL at 80 Hz | 118.9 dB |
| Output SPL at 100 Hz | 119.1 dB |
| Output SPL at 125 Hz | 118.9 dB |
| Warranty | 5 |
| Weight | 80 lbs (36.3 kg) |
- Reviews, Comparisons and Sound Samples
- These figures are manufacturer-specified rather than independently measured.
- Head-to-Head Comparisons
- Monoprice Monolith M15-S vs Rythmik F18
- Monoprice Monolith M15-S vs Monoprice Monolith M-15 V2
- Monoprice Monolith M15-S vs HSU Research VTF-3 MK5 HP
- Monoprice Monolith M15-S vs HSU Research VTF-15H MK2
- Monoprice Monolith M15-S vs Rythmik FV15HP
- Monoprice Monolith M15-S vs Monoprice Monolith M-215
- Monoprice Monolith M15-S vs Reaction Audio PV-15X
- Monoprice Monolith M15-S vs Monoprice Monolith 16 THX Ultra
- See all 15 comparisons
SVS PB-4000: $2,158.97 Discontinued Amazon eBay
Newer model: the SVS PB-5000 R-Evolution, ranked lower, estimated 4.2/5.
Same family: the SVS PB-1000 (smaller subwoofer, rated 3.6/5), the SVS PB-2000 (smaller subwoofer, rated 4.1/5) and the SVS PB-3000 (smaller subwoofer, ranked higher, rated 4.2/5).
Pros: Independent CEA-2010 testing records 115.3 dB at 20 Hz and 120.3 dB through 40-80 Hz. The ported, front enclosure with 13.5” (343mm) driver with ported design has the headroom for demanding film bass in a large room.
Cons: The 594.4H x 520.7W x 703.6D mm cabinet and 69.5 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential. Discontinued.
Full SVS PB-4000 review and specifications →
| AES Input | No |
|---|---|
| Aux Input | No |
| CEA-2010-A Average (40-80Hz) | 120.3 dB |
| Cabinet Color | black |
| Coaxial Input | No |
| Country | United States |
| Dimensions | 23.4”H x 20.5”W x 27.7”D (594.4 x 520.7 x 703.6 mm) |
| Drivers | 13.5” (343mm) driver with ported design |
| Enclosure | ported, front |
| HDMI Input | No |
| Inputs | XLR (balanced), RCA (LFE/stereo) |
| Measurement Source | Audioholics |
| Optical Input | No |
| Output SPL at 15 Hz | 102.1 dB |
| Output SPL at 20 Hz | 115.3 dB |
| Output SPL at 25 Hz | 116.3 dB |
| Output SPL at 31.5 Hz | 117.8 dB |
| Output SPL at 40 Hz | 119.8 dB |
| Output SPL at 50 Hz | 121.7 dB |
| Output SPL at 63 Hz | 120.7 dB |
| Output SPL at 80 Hz | 119.2 dB |
| Output SPL at 100 Hz | 118.1 dB |
| Output SPL at 125 Hz | 117.5 dB |
| RCA Input | Yes |
| TRS Input | No |
| USB Input | No |
| Warranty | 5 |
| Weight | 153.2 lbs (69.5 kg) |
| XLR Input | Yes |
- 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
- SVS PB-4000 vs SVS SB-4000
- SVS PB-4000 vs Monoprice Monolith M-15 V2
- SVS PB-4000 vs HSU Research VTF-3 MK5 HP
- SVS PB-4000 vs HSU Research VTF-15H MK2
- SVS PB-4000 vs Rythmik F18
- SVS PB-4000 vs Rythmik FV15HP
- SVS PB-4000 vs JTR Speakers Captivator 1400
- SVS PB-4000 vs Monoprice Monolith M-215
- See all 24 comparisons