Short answer: the WW Speaker Cabinets X21 - B&C 21DS115-4. It ranks #3 of 143 subwoofers by sound quality (rated 4.6/5) at $3,995 and is still sold new; the HSU Research VTF-15H MK2 ranks #57 (rated 4.2/5) and is discontinued, so it is only an option used. The HSU Research VTF-15H MK2’s replacement, the HSU Research VTF-TN1, is rated 3.9/5 at $1,249.
What the HSU Research VTF-15H MK2 does well: A 15 inch ported subwoofer from a long running series, with strong output for movies at a reasonable price. The tradeoff: Ported enclosure prone to room modes at certain frequencies, mid-large 110.2 lbs (50 kg) size, and $1499 price point.
The WW Speaker Cabinets X21 - B&C 21DS115-4 is the better-sounding choice. A passive 21 inch ported subwoofer with enormous output, made for big home theater rooms. Watch for: Premium $3995 price, massive 114.6 lbs (52 kg) cabinet, and ported room gain dependency.
Buy the WW Speaker Cabinets X21 - B&C 21DS115-4. It is rated higher for sound quality; the HSU Research VTF-15H MK2 is no longer sold new.
Still deciding? The full Subwoofers rankings cover every ranked option.
A 15 inch ported subwoofer from a long running series, with strong output for movies at a reasonable price.
A passive 21 inch ported subwoofer with enormous output, made for big home theater rooms.
Prices on this page were last checked October 31, 2026 at 7:11 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
| HSU Research VTF-15H MK2 | WW Speaker Cabinets X21 - B&C 21DS115-4 | |
|---|---|---|
| Price | $1,499 Discontinued | $3,995 Passive |
| Ranked | #57 of 143 in Large Home Subwoofers (Over 75 lbs) | #3 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Output SPL at 15 Hz | 101.6 dB | 111.9 dB |
| Output SPL at 20 Hz | 108.4 dB | 121.9 dB |
| Output SPL at 25 Hz | 114.8 dB | 120.8 dB |
| Output SPL at 31.5 Hz | 119.4 dB | 122.5 dB |
| Output SPL at 40 Hz | 122.9 dB | 126.7 dB |
| Output SPL at 50 Hz | 122.5 dB | 129.2 dB |
| Output SPL at 63 Hz | 121.1 dB | 132.9 dB |
| Output SPL at 80 Hz | 120.5 dB | 136.3 dB |
| CEA-2010-A Average (40-80Hz) | 121.8 dB | 131.3 dB |
| Dimensions | 24”H x 18”W x 26”D (609.6 x 457.2 x 660.4 mm) | 24”H x 32”W x 32”D (609.6 x 812.8 x 812.8 mm) |
| Weight | 110 lbs (49.9 kg) | 115.1 lbs (52.2 kg) |
| Warranty | 7/2(+3) | - |
| Cabinet Color | black, wood | - |
| Country | United States | United States |
| Measurement Source | Manufacturer | Data-bass |
| Drivers | 15” (381mm) driver | 21” (533mm) driver |
| Passive | - | Yes |
| Output SPL at 12.5 Hz | - | 96.2 dB |
| Output SPL at 100 Hz | - | 139.0 dB |
| Output SPL at 125 Hz | - | 140.1 dB |
Related Speaker Comparisons
How WW Speaker Cabinets X21 - B&C 21DS115-4 compares with other leading options:
- Pro Audio Technology LFC-24sm vs WW Speaker Cabinets X21 - B&C 21DS115-4
- JTR Speakers Captivator S2 vs WW Speaker Cabinets X21 - B&C 21DS115-4
- JTR Speakers Growler (2015) vs WW Speaker Cabinets X21 - B&C 21DS115-4
- Danley Sound Labs DTS10 vs WW Speaker Cabinets X21 - B&C 21DS115-4
- Monoprice Monolith 16 THX Ultra vs WW Speaker Cabinets X21 - B&C 21DS115-4