JTR Speakers Captivator 4000ULF vs Rythmik F18

Last updated: August 9, 2026

Short answer: the JTR Speakers Captivator 4000ULF for the higher ranking, the Rythmik F18 for the lower price. The JTR Speakers Captivator 4000ULF ranks #4 of 97 subwoofers at $5000. The Rythmik F18 ranks #60 at $1850, $3150 cheaper.

Buy the JTR Speakers Captivator 4000ULF if the ranking matters more than the price. Buy the Rythmik F18 if the price matters more than the ranking.

Specifications Side By Side

JTR Speakers Captivator 4000ULF Rythmik F18
Price$5,000$1,850
Ranked#4 of 97 in Large Powered Home Subwoofers (Over 75 lbs)#60 of 97 in Large Powered Home Subwoofers (Over 75 lbs)
Enclosureported, frontsealed
Output SPL at 10 Hz111.0 dB93.7 dB
Output SPL at 12.5 Hz115.3 dB97.4 dB
Output SPL at 15 Hz119.3 dB102.0 dB
Output SPL at 20 Hz122.3 dB106.2 dB
Output SPL at 25 Hz126.1 dB110.9 dB
Output SPL at 31.5 Hz129.3 dB114.3 dB
Output SPL at 40 Hz130.7 dB117.1 dB
Output SPL at 50 Hz131.2 dB119.1 dB
Output SPL at 63 Hz130.9 dB120.5 dB
Output SPL at 80 Hz130.6 dB121.2 dB
Output SPL at 100 Hz130.5 dB121.4 dB
Output SPL at 125 Hz129.5 dB121.4 dB
CEA-2010-A Average (40-80Hz)130.8 dB119.5 dB
Dimensions41.0"H x 20.5"W x 39.5"D (1041.4 x 520.7 x 1003.3 mm)20.5"H x 20.5"W x 21.0"D (520.7 x 520.7 x 533.4 mm)
Weight265 lbs / 120.2 kg115.1 lbs / 52.2 kg
Warranty5/35/3
Cabinet Colorblack, customblack
CountryUnited StatesUnited States
Measurement SourceData-bassData-bass
Drivers2x 18" (457mm) driver18" (457mm) driver

The Two Speakers In Full

JTR Speakers Captivator 4000ULF: $5,000

JTR Speakers Captivator 4000ULF ranking card

CEA-2010-A Average (40-80Hz)130.8 dB
Cabinet Colorblack, custom
CountryUnited States
Dimensions41.0"H x 20.5"W x 39.5"D (1041.4 x 520.7 x 1003.3 mm)
Drivers2x 18" (457mm) driver
Enclosureported, front
Measurement SourceData-bass
Output SPL at 10 Hz111.0 dB
Output SPL at 12.5 Hz115.3 dB
Output SPL at 15 Hz119.3 dB
Output SPL at 20 Hz122.3 dB
Output SPL at 25 Hz126.1 dB
Output SPL at 31.5 Hz129.3 dB
Output SPL at 40 Hz130.7 dB
Output SPL at 50 Hz131.2 dB
Output SPL at 63 Hz130.9 dB
Output SPL at 80 Hz130.6 dB
Output SPL at 100 Hz130.5 dB
Output SPL at 125 Hz129.5 dB
Warranty5/3
Weight265 lbs / 120.2 kg

Rythmik F18: $1,850

Rythmik F18 ranking card

CEA-2010-A Average (40-80Hz)119.5 dB
Cabinet Colorblack
CountryUnited States
Dimensions20.5"H x 20.5"W x 21.0"D (520.7 x 520.7 x 533.4 mm)
Drivers18" (457mm) driver
Enclosuresealed
Measurement SourceData-bass
Output SPL at 10 Hz93.7 dB
Output SPL at 12.5 Hz97.4 dB
Output SPL at 15 Hz102.0 dB
Output SPL at 20 Hz106.2 dB
Output SPL at 25 Hz110.9 dB
Output SPL at 31.5 Hz114.3 dB
Output SPL at 40 Hz117.1 dB
Output SPL at 50 Hz119.1 dB
Output SPL at 63 Hz120.5 dB
Output SPL at 80 Hz121.2 dB
Output SPL at 100 Hz121.4 dB
Output SPL at 125 Hz121.4 dB
Warranty5/3
Weight115.1 lbs / 52.2 kg

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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.