Short answer: the WW Speaker Cabinets X21 - B&C 21DS115-4 if sound quality matters most, the Reaction Audio PV-15X if price matters most. The WW Speaker Cabinets X21 - B&C 21DS115-4 ranks #3 of 110 subwoofers at $3995. The Reaction Audio PV-15X ranks #21 at $1999, $1996 cheaper.
What the Reaction Audio PV-15X offers: 15-inch ported driver delivers 126.2dB CEA-2010-A average from a purpose-built cinema-style cabinet. Watch for: Passive design requires a separate external amplifier and weighs 68 kg.
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 Reaction Audio PV-15X when the price outweighs sound quality for you, and the WW Speaker Cabinets X21 - B&C 21DS115-4 when sound quality outweighs the price instead.
Want more options? Browse the full Subwoofers rankings.
Specifications Side By Side
| Reaction Audio PV-15X | WW Speaker Cabinets X21 - B&C 21DS115-4 | |
|---|---|---|
| Price | $1999 Discontinued | $3995 Passive |
| Ranked | #21 of 110 in Large Home Subwoofers (Over 75 lbs) | #3 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, rear | ported, front |
| Output SPL at 15 Hz | 105.3 dB | 111.9 dB |
| Output SPL at 20 Hz | 111.3 dB | 121.9 dB |
| Output SPL at 25 Hz | 116.1 dB | 120.8 dB |
| Output SPL at 31.5 Hz | 119.8 dB | 122.5 dB |
| Output SPL at 40 Hz | 125.3 dB | 126.7 dB |
| Output SPL at 50 Hz | 126.8 dB | 129.2 dB |
| Output SPL at 63 Hz | 126.1 dB | 132.9 dB |
| Output SPL at 80 Hz | 126.5 dB | 136.3 dB |
| Output SPL at 100 Hz | 126.4 dB | 139.0 dB |
| Output SPL at 125 Hz | 126.1 dB | 140.1 dB |
| CEA-2010-A Average (40-80Hz) | 126.2 dB | 131.3 dB |
| Dimensions | 18"H x 22"W x 29"D (457.2 x 558.8 x 736.6 mm) | 24"H x 32"W x 32"D (609.6 x 812.8 x 812.8 mm) |
| Measurement Source | Data-bass | Data-bass |
| Discontinued | Yes | - |
| Weight | 149.9 lbs (68 kg) | 115.1 lbs (52.2 kg) |
| Drivers | 15" (381mm) driver | 21" (533mm) driver |
| Passive | - | Yes |
| Output SPL at 12.5 Hz | - | 96.2 dB |
Related Speaker Comparisons
More worthwhile head-to-heads for WW Speaker Cabinets X21 - B&C 21DS115-4:
- 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 14, 2026 at 1:47 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
Reaction Audio PV-15X: $1999 Discontinued eBay
Pros: 15-inch ported driver delivers 126.2dB CEA-2010-A average from a purpose-built cinema-style cabinet.
Cons: Passive design requires a separate external amplifier and weighs 68 kg. Discontinued.
Full Reaction Audio PV-15X review and specifications →
| CEA-2010-A Average (40-80Hz) | 126.2 dB |
|---|---|
| Dimensions | 18"H x 22"W x 29"D (457.2 x 558.8 x 736.6 mm) |
| Discontinued | Yes |
| Drivers | 15" (381mm) driver |
| Enclosure | ported, rear |
| Measurement Source | Data-bass |
| Output SPL at 15 Hz | 105.3 dB |
| Output SPL at 20 Hz | 111.3 dB |
| Output SPL at 25 Hz | 116.1 dB |
| Output SPL at 31.5 Hz | 119.8 dB |
| Output SPL at 40 Hz | 125.3 dB |
| Output SPL at 50 Hz | 126.8 dB |
| Output SPL at 63 Hz | 126.1 dB |
| Output SPL at 80 Hz | 126.5 dB |
| Output SPL at 100 Hz | 126.4 dB |
| Output SPL at 125 Hz | 126.1 dB |
| Weight | 149.9 lbs (68 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
- Reaction Audio PV-15X vs JTR Speakers Captivator 2400
- Reaction Audio PV-15X vs Funk Audio Ultra 21.0LX
- Reaction Audio PV-15X vs Monoprice Monolith M-215
- Reaction Audio PV-15X vs Monoprice Monolith 16 THX Ultra
- Reaction Audio PV-15X vs JBL 4645C
- Reaction Audio PV-15X vs Danley Sound Labs DTS10
- Reaction Audio PV-15X vs JTR Speakers Growler (2015)
- Reaction Audio PV-15X vs Chase Home Theater SS18.1
- See all 23 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 JBL 4645C
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs Chase Home Theater SS18.1
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs HSU Research VTF-3 MK5 HP