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 JBL 4645C ranks #25 (rated 4.4/5) and is discontinued, so it is only an option used.
Buy the WW Speaker Cabinets X21 - B&C 21DS115-4. It is rated higher for sound quality and still sold new, while the JBL 4645C is discontinued.
Still deciding? The full Subwoofers rankings cover every ranked option.
Prices on this page were last checked November 7, 2026 at 7:34 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.
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Specifications Side By Side
| JBL 4645C | WW Speaker Cabinets X21 - B&C 21DS115-4 | |
|---|---|---|
| Price | $4,999 Passive, Discontinued | $3,995 Passive |
| Ranked | #25 of 143 in Large Home Subwoofers (Over 75 lbs) | #3 of 143 in Large Home Subwoofers (Over 75 lbs) |
| Enclosure | ported, front | ported, front |
| Passive | Yes | Yes |
| Output SPL at 20 Hz | 98.9 dB | 121.9 dB |
| Output SPL at 25 Hz | 114.0 dB | 120.8 dB |
| Output SPL at 31.5 Hz | 118.7 dB | 122.5 dB |
| Output SPL at 40 Hz | 122.0 dB | 126.7 dB |
| Output SPL at 50 Hz | 123.7 dB | 129.2 dB |
| Output SPL at 63 Hz | 129.7 dB | 132.9 dB |
| Output SPL at 80 Hz | 133.9 dB | 136.3 dB |
| Output SPL at 100 Hz | 135.1 dB | 139.0 dB |
| Output SPL at 125 Hz | 135.8 dB | 140.1 dB |
| CEA-2010-A Average (40-80Hz) | 127.3 dB | 131.3 dB |
| Dimensions | 39.7”H x 26.5”W x 17.7”D (1009.6 x 673.1 x 450.8 mm) | 24”H x 32”W x 32”D (609.6 x 812.8 x 812.8 mm) |
| Weight | 138 lbs (62.6 kg) | 115.1 lbs (52.2 kg) |
| Warranty | 5/3/2 | - |
| Cabinet Color | black | - |
| Country | United States | United States |
| Measurement Source | Data-bass | Data-bass |
| Drivers | 18” (457mm) driver | 21” (533mm) driver |
| Output SPL at 12.5 Hz | - | 96.2 dB |
| Output SPL at 15 Hz | - | 111.9 dB |
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