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 #141 (rated 3.3/5) for the BK Electronics Monolith-DF. If you want one new, the JTR Speakers Orbit Shifter PRO ranks #1 at $4,499.
What the BK Electronics Monolith-DF does well: Independent CEA-2010 testing records 102.0 dB at 20 Hz and 108.4 dB through 40-80 Hz. The catch: 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 Harbinger V2218S is the better-sounding pick. Independent CEA-2010 testing records 81.7 dB at 20 Hz and 128.9 dB through 40-80 Hz. 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 Orbit Shifter PRO instead.
Want more options? Browse the full Subwoofers rankings.
Independent CEA-2010 testing records 102.0 dB at 20 Hz and 108.4 dB through 40-80 Hz.
eBay
Independent CEA-2010 testing records 81.7 dB at 20 Hz and 128.9 dB through 40-80 Hz.
eBayPrices on this page were last checked October 16, 2026 at 5:46 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
| BK Electronics Monolith-DF | Harbinger V2218S | |
|---|---|---|
| Price | £406.95 Discontinued | $3,495 Discontinued |
| Ranked | #141 of 143 in Large Home Subwoofers (Over 75 lbs) | #15 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, bottom | ported, front |
| Output SPL at 15 Hz | 91.3 dB | - |
| Output SPL at 20 Hz | 102.0 dB | 81.7 dB |
| Output SPL at 25 Hz | 106.4 dB | 99.7 dB |
| Output SPL at 31.5 Hz | 108.3 dB | 118.0 dB |
| Output SPL at 40 Hz | 108.6 dB | 122.8 dB |
| Output SPL at 50 Hz | 108.7 dB | 129.0 dB |
| Output SPL at 63 Hz | 108.6 dB | 132.2 dB |
| Output SPL at 80 Hz | 107.7 dB | 131.7 dB |
| CEA-2010-A Average (40-80Hz) | 108.4 dB | 128.9 dB |
| Dimensions | 23.8”H x 21.3”W x 16.5”D (603.8 x 539.8 x 419.9 mm) | 32.5”H x 26.5”W x 29.7”D (825.5 x 673.1 x 754.4 mm) |
| Weight | 103.2 lbs (46.8 kg) | 89.9 lbs (40.8 kg) |
| Warranty | 2 | - |
| Cabinet Color | black, wood | black |
| Country | United Kingdom | United States |
| Measurement Source | Ilkka Rissanen | Brent Butterworth |
| Drivers | 12” (305mm) driver with ported design | 18” (457mm) driver |
| Inputs | XLR (balanced), RCA (unbalanced) | - |
| 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
How Harbinger V2218S compares with other leading options: