Short answer: both are discontinued, so this only matters if you are buying used. Used, the Harbinger V2218S is the better pick: it ranks #15 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 Captivator 215PRO ranks #7 at $3,500.
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. The tradeoff: Heavy at 172 lbs (78 kg) and ported design can interact with room acoustics.
Why pick the Harbinger V2218S: A pro style 18 inch ported subwoofer with hard hitting upper bass for movie effects and music, relatively light for its output. The tradeoff: 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.
Buy the Harbinger V2218S 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 Captivator 215PRO instead.
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 pro style 18 inch ported subwoofer with hard hitting upper bass for movie effects and music, relatively light for its output.
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Specifications Side By Side
| Monoprice Monolith 16 THX Ultra | Harbinger V2218S | |
|---|---|---|
| Price | $2,300 Discontinued | $3,495 Discontinued |
| Ranked | #19 of 143 in Large Home Subwoofers (Over 75 lbs) | #15 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 | 81.7 dB |
| Output SPL at 25 Hz | 123.3 dB | 99.7 dB |
| Output SPL at 31.5 Hz | 125.1 dB | 118.0 dB |
| Output SPL at 40 Hz | 126.3 dB | 122.8 dB |
| Output SPL at 50 Hz | 126.5 dB | 129.0 dB |
| Output SPL at 63 Hz | 126.6 dB | 132.2 dB |
| Output SPL at 80 Hz | 126.8 dB | 131.7 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 | 128.9 dB |
| Dimensions | 25.6”H x 22”W x 28.1”D (650.2 x 558.8 x 713.7 mm) | 32.5”H x 26.5”W x 29.7”D (825.5 x 673.1 x 754.4 mm) |
| Weight | 171.5 lbs (77.8 kg) | 89.9 lbs (40.8 kg) |
| Warranty | 5 | - |
| Cabinet Color | black | black |
| Country | United States | United States |
| Measurement Source | Audioholics | Brent Butterworth |
| Drivers | 16” (406mm) driver | 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 | - |
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