Short answer: the WW Speaker Cabinets X21 for the last decibel, the JTR Growler for about $1000 less. The X21’s 21-inch driver in a large ported cabinet delivers 131.3dB CEA-2010-A average, the highest output of any passive subwoofer tested. The Growler’s 12-inch ported driver reaches 130.2dB, nearly matching it, though it still brings ported room interaction and a 45 kg frame.
The case for the JTR Speakers Growler (2015): 12-inch ported driver reaches 130.2dB CEA-2010-A average, nearly matching the class leader for about $1000 less. The tradeoff: Ported design room interaction, 45 kg (99.2 lbs) size, and $2,995 cost.
What the WW Speaker Cabinets X21 - B&C 21DS115-4 gets right: 21-inch driver in a large ported cabinet delivers 131.3dB CEA-2010-A average, the highest output of any passive subwoofer tested. The catch: Premium $3,995 price, massive 52 kg (114.6 lbs) cabinet, and ported room gain dependency.
Buy the JTR Speakers Growler (2015) 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
| JTR Speakers Growler (2015) | WW Speaker Cabinets X21 - B&C 21DS115-4 | |
|---|---|---|
| Price | $2995 Passive | $3995 Passive |
| Ranked | #13 of 110 in Large Home Subwoofers (Over 75 lbs) | #3 of 110 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Passive | Yes | Yes |
| Output SPL at 20 Hz | 92.8 dB | 121.9 dB |
| Output SPL at 25 Hz | 97.2 dB | 120.8 dB |
| Output SPL at 31.5 Hz | 106.6 dB | 122.5 dB |
| Output SPL at 40 Hz | 122.7 dB | 126.7 dB |
| Output SPL at 50 Hz | 130.0 dB | 129.2 dB |
| Output SPL at 63 Hz | 133.6 dB | 132.9 dB |
| Output SPL at 80 Hz | 134.4 dB | 136.3 dB |
| Output SPL at 100 Hz | 135.5 dB | 139.0 dB |
| Output SPL at 125 Hz | 136.0 dB | 140.1 dB |
| CEA-2010-A Average (40-80Hz) | 130.2 dB | 131.3 dB |
| Dimensions | 22.5"H x 30"W x 20"D (571.5 x 762.0 x 508.0 mm) | 24"H x 32"W x 32"D (609.6 x 812.8 x 812.8 mm) |
| Country | United States | United States |
| Measurement Source | Data-bass | Data-bass |
| Weight | 100.1 lbs (45.4 kg) | 115.1 lbs (52.2 kg) |
| Drivers | 12" (305mm) driver | 21" (533mm) driver |
| Warranty | 5 years | - |
| Output SPL at 12.5 Hz | - | 96.2 dB |
| Output SPL at 15 Hz | - | 111.9 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
- 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
- Reaction Audio PV-15X vs WW Speaker Cabinets X21 - B&C 21DS115-4
Prices on this page were last checked September 22, 2026 at 5:11 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
JTR Speakers Growler (2015): $2995 Passive eBay
Pros: 12-inch ported driver reaches 130.2dB CEA-2010-A average, nearly matching the class leader for about $1,000 less.
Cons: Ported design room interaction, 45 kg size, and $2995 cost.
Notes: Looks like “PA sub”
Full JTR Speakers Growler (2015) review and specifications →
| CEA-2010-A Average (40-80Hz) | 130.2 dB |
|---|---|
| Country | United States |
| Dimensions | 22.5"H x 30"W x 20"D (571.5 x 762.0 x 508.0 mm) |
| Drivers | 12" (305mm) driver |
| Enclosure | ported, front |
| Measurement Source | Data-bass |
| Output SPL at 20 Hz | 92.8 dB |
| Output SPL at 25 Hz | 97.2 dB |
| Output SPL at 31.5 Hz | 106.6 dB |
| Output SPL at 40 Hz | 122.7 dB |
| Output SPL at 50 Hz | 130.0 dB |
| Output SPL at 63 Hz | 133.6 dB |
| Output SPL at 80 Hz | 134.4 dB |
| Output SPL at 100 Hz | 135.5 dB |
| Output SPL at 125 Hz | 136.0 dB |
| Passive | Yes |
| Warranty | 5 years |
| Weight | 100.1 lbs (45.4 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
- JTR Speakers Growler (2015) vs Danley Sound Labs DTS10
- JTR Speakers Growler (2015) vs Harbinger V2218S
- JTR Speakers Growler (2015) vs Funk Audio Ultra 24.0
- JTR Speakers Growler (2015) vs Funk Audio Classic 18.0
- JTR Speakers Growler (2015) vs JTR Speakers Captivator S2
- JTR Speakers Growler (2015) vs Monoprice Monolith 16 THX Ultra
- JTR Speakers Growler (2015) vs Reaction Audio PV-15X
- JTR Speakers Growler (2015) vs Pro Audio Technology LFC-24sm
- 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 $3995 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 |
|---|---|
| Country | United States |
| 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 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
- WW Speaker Cabinets X21 - B&C 21DS115-4 vs HSU Research VTF-15H MK2
- See all 9 comparisons