Short answer: both are discontinued, so this only matters if you are buying used. Used, the Power Sound Audio (PSA) V3600I is the better pick: it ranks #10 of 143 subwoofers by sound quality (rated 4.5/5), against #19 (rated 4.4/5) for the Monoprice Monolith 16 THX Ultra. If you want one new, the JTR Speakers Orbit Shifter PRO ranks #1 at $4,499.
The case for the Monoprice Monolith 16 THX Ultra: A THX Ultra certified 16 inch ported subwoofer with huge output for far less money than most rivals, now worth finding used. Watch for: Heavy at 172 lbs (78 kg) and ported design can interact with room acoustics.
Why pick the Power Sound Audio (PSA) V3600I: A towering dual 18 inch ported subwoofer with very strong output down to the lowest notes, made for big home theaters. Watch for: The 1117.6H x 508.0W x 635.0D mm cabinet and 196 lbs (88.9 kg) mass make this a serious placement and moving commitment.
Buy the Power Sound Audio (PSA) V3600I 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, start with the JTR Speakers Orbit Shifter PRO instead.
Still deciding? The full Subwoofers rankings cover every ranked option.
A THX Ultra certified 16 inch ported subwoofer with huge output for far less money than most rivals, now worth finding used.
A towering dual 18 inch ported subwoofer with very strong output down to the lowest notes, made for big home theaters.
Prices on this page were last checked October 29, 2026 at 4:42 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.
As an eBay Partner, we may be compensated if you make a purchase.
Specifications Side By Side
| Monoprice Monolith 16 THX Ultra | Power Sound Audio (PSA) V3600I | |
|---|---|---|
| Price | $2,300 Discontinued | $6,995 Discontinued |
| Ranked | #19 of 143 in Large Home Subwoofers (Over 75 lbs) | #10 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Output SPL at 15 Hz | 107.3 dB | - |
| Output SPL at 20 Hz | 118.4 dB | 119.4 dB |
| Output SPL at 25 Hz | 123.3 dB | 119.4 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 119.4 dB |
| Output SPL at 40 Hz | 126.3 dB | 128.3 dB |
| Output SPL at 50 Hz | 126.5 dB | 128.3 dB |
| Output SPL at 63 Hz | 126.6 dB | 128.3 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 | 128.3 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) | 44”H x 20”W x 25”D (1117.6 x 508.0 x 635.0 mm) |
| Weight | 171.5 lbs (77.8 kg) | 196 lbs (88.9 kg) |
| Warranty | 5 | 5 |
| Cabinet Color | black | - |
| Country | United States | United States |
| Measurement Source | Audioholics | Manufacturer |
| Drivers | 16” (406mm) driver | 2x 18” (457mm) driver |
| Inputs | XLR, RCA, XLR out | - |
| 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 | - |
Related Speaker Comparisons
More top alternatives to Power Sound Audio (PSA) V3600I: