Short answer: the WW Speaker Cabinets X21 - B&C 21DS115-4 for better sound quality, the HSU Research VTF-15H MK2 for the lower price. The WW Speaker Cabinets X21 - B&C 21DS115-4 ranks #3 of 110 subwoofers at $3995. The HSU Research VTF-15H MK2 ranks #50 at $1499, $2496 cheaper.
What the HSU Research VTF-15H MK2 offers: 15-inch ported driver delivers 121.8dB CEA-2010-A average from HSU Research’s long-running VTF series. Watch for: Ported enclosure prone to room modes at certain frequencies, mid-large 50 kg size, and $1,500 price point.
What the WW Speaker Cabinets X21 - B&C 21DS115-4 offers: 21-inch driver in a large ported cabinet delivers 131.3dB CEA-2010-A average, the highest output of any passive subwoofer tested. Watch for: Premium $3,995 price, massive 52 kg cabinet, and ported room gain dependency.
Buy the HSU Research VTF-15H MK2 if the price matters more than sound quality. Buy the WW Speaker Cabinets X21 - B&C 21DS115-4 if sound quality matters more than the price.
Still deciding? The full Subwoofers rankings cover every ranked option.
Specifications Side By Side
| HSU Research VTF-15H MK2 | WW Speaker Cabinets X21 - B&C 21DS115-4 | |
|---|---|---|
| Price | $1,499 | $3995 Passive |
| Ranked | #50 of 110 in Large Home Subwoofers (Over 75 lbs) | #3 of 110 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 | - |
| 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
Prices on this page were last checked September 16, 2026 at 12:41 AM 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
HSU Research VTF-15H MK2: $1,499 eBay
Pros: 15-inch ported driver delivers 121.8dB CEA-2010-A average from HSU Research’s long-running VTF series.
Cons: Ported enclosure prone to room modes at certain frequencies, mid-large 50 kg size, and $1,500 price point.
Notes: Price includes shipping
Full HSU Research VTF-15H MK2 review and specifications →
| CEA-2010-A Average (40-80Hz) | 121.8 dB |
|---|---|
| Cabinet Color | black, wood |
| Country | United States |
| Dimensions | 24"H x 18"W x 26"D (609.6 x 457.2 x 660.4 mm) |
| Drivers | 15" (381mm) driver |
| Enclosure | ported, front |
| Measurement Source | Manufacturer |
| Output SPL at 15 Hz | 101.6 dB |
| Output SPL at 20 Hz | 108.4 dB |
| Output SPL at 25 Hz | 114.8 dB |
| Output SPL at 31.5 Hz | 119.4 dB |
| Output SPL at 40 Hz | 122.9 dB |
| Output SPL at 50 Hz | 122.5 dB |
| Output SPL at 63 Hz | 121.1 dB |
| Output SPL at 80 Hz | 120.5 dB |
| Warranty | 7/2(+3) |
| Weight | 110 lbs (49.9 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- These figures are manufacturer-specified rather than independently measured.
- Head-to-Head Comparisons
- HSU Research VTF-15H MK2 vs SVS PB-3000
- HSU Research VTF-15H MK2 vs HSU Research VTF-3 MK5 HP
- HSU Research VTF-15H MK2 vs Rythmik FV15HP
- HSU Research VTF-15H MK2 vs SVS PB-4000
- HSU Research VTF-15H MK2 vs Monoprice Monolith M-15 V2
- HSU Research VTF-15H MK2 vs Chase Home Theater SS18.1
- HSU Research VTF-15H MK2 vs Rythmik F18
- HSU Research VTF-15H MK2 vs Monoprice Monolith M15-S
- See all 22 comparisons
WW Speaker Cabinets X21 - B&C 21DS115-4: $3995 Passive eBay
Pros: 21-inch driver in a large ported cabinet delivers 131.3dB CEA-2010-A average, the highest output of any passive subwoofer tested.
Cons: Premium $3,995 price, massive 52 kg cabinet, and ported room gain dependency.
Full WW Speaker Cabinets X21 - B&C 21DS115-4 review and specifications →
| CEA-2010-A Average (40-80Hz) | 131.3 dB |
|---|---|
| Dimensions | 24"H x 32"W x 32"D (609.6 x 812.8 x 812.8 mm) |
| Drivers | 21" (533mm) driver |
| Enclosure | ported, front |
| Measurement Source | Data-bass |
| Output SPL at 12.5 Hz | 96.2 dB |
| Output SPL at 15 Hz | 111.9 dB |
| Output SPL at 20 Hz | 121.9 dB |
| Output SPL at 25 Hz | 120.8 dB |
| Output SPL at 31.5 Hz | 122.5 dB |
| Output SPL at 40 Hz | 126.7 dB |
| Output SPL at 50 Hz | 129.2 dB |
| Output SPL at 63 Hz | 132.9 dB |
| Output SPL at 80 Hz | 136.3 dB |
| Output SPL at 100 Hz | 139.0 dB |
| Output SPL at 125 Hz | 140.1 dB |
| Passive | Yes |
| Weight | 115.1 lbs (52.2 kg) |
- Reviews, Comparisons and Sound Samples
- Independently measured by Data-bass; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Pro Audio Technology LFC-24sm
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs JTR Speakers Captivator S2
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs JTR Speakers Growler (2015)
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Danley Sound Labs DTS10
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Monoprice Monolith 16 THX Ultra
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Reaction Audio PV-15X
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs JBL 4645C
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Chase Home Theater SS18.1
- See all 9 comparisons