JTR Speakers Captivator S2 vs Funk Audio Ultra 21.0LX

Short answer: the JTR Speakers Captivator S2. It ranks #9 of 110 subwoofers by sound quality at $3995; the Funk Audio Ultra 21.0LX ranks #19 and costs $9487.26, which makes this an easy call rather than a real tradeoff.

What the JTR Speakers Captivator S2 offers: Independent CEA-2010 testing records 115.1 dB at 20 Hz and 129.4 dB through 40-80 Hz. The sealed enclosure with 2x 18” (457mm) drivers has the headroom for demanding film bass in a large room. Watch for: The 1016.0H x 533.4W x 457.2D mm cabinet and 99.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.

What the Funk Audio Ultra 21.0LX offers: Published CEA-2010 specifications list 116.6 dB at 20 Hz and 126.3 dB through 40-80 Hz. The sealed enclosure with 21” (533mm) driver has the headroom for demanding film bass in a large room. Watch for: The 647.7H x 622.3W x 609.6D mm cabinet and 65.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.

Buy the JTR Speakers Captivator S2. It ranks higher for sound quality than the Funk Audio Ultra 21.0LX and costs less, which settles it without a real tradeoff to make.

Looking for alternatives? See the complete Subwoofers rankings.

Specifications Side By Side

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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

JTR Speakers Captivator S2: $3995 eBay

Pros: Independent CEA-2010 testing records 115.1 dB at 20 Hz and 129.4 dB through 40-80 Hz. The sealed enclosure with 2x 18” (457mm) drivers has the headroom for demanding film bass in a large room.

Cons: The 1016.0H x 533.4W x 457.2D mm cabinet and 99.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.

Notes: Replaced by “RS2”

Full JTR Speakers Captivator S2 review and specifications →

CEA-2010-A Average (40-80Hz)	129.4 dB
Country	United States
Dimensions	40"H x 21"W x 18"D (1016.0 x 533.4 x 457.2 mm)
Drivers	2x 18" (457mm) drivers
Enclosure	sealed
Measurement Source	Data-bass
Output SPL at 10 Hz	100.3 dB
Output SPL at 12.5 Hz	103.3 dB
Output SPL at 15 Hz	108.7 dB
Output SPL at 20 Hz	115.1 dB
Output SPL at 25 Hz	119.7 dB
Output SPL at 31.5 Hz	124.8 dB
Output SPL at 40 Hz	129.3 dB
Output SPL at 50 Hz	130.3 dB
Output SPL at 63 Hz	129.4 dB
Output SPL at 80 Hz	128.5 dB
Output SPL at 100 Hz	128.1 dB
Output SPL at 125 Hz	128.0 dB
Warranty	5/3
Weight	220 lbs (99.8 kg)

• Links
  • JTR Speakers Captivator S2 Website
• 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
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  • JTR Speakers Captivator S2 vs Power Sound Audio (PSA) V3600I
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  • JTR Speakers Captivator S2 vs JTR Speakers Captivator 4000ULF
  • JTR Speakers Captivator S2 vs Funk Audio Custom 21.0
  • JTR Speakers Captivator S2 vs Power Sound Audio (PSA) TRIAX
  • JTR Speakers Captivator S2 vs JTR Speakers Growler (2015)
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Funk Audio Ultra 21.0LX: $9,487.26 eBay

Pros: Published CEA-2010 specifications list 116.6 dB at 20 Hz and 126.3 dB through 40-80 Hz. The sealed enclosure with 21” (533mm) driver has the headroom for demanding film bass in a large room.

Cons: The 647.7H x 622.3W x 609.6D mm cabinet and 65.8 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks.

Full Funk Audio Ultra 21.0LX review and specifications →

CEA-2010-A Average (40-80Hz)	126.3 dB
Cabinet Color	wood, custom
Country	Canada
Dimensions	25.5"H x 24.5"W x 24"D (647.7 x 622.3 x 609.6 mm)
Drivers	21" (533mm) driver
Enclosure	sealed
Measurement Source	Manufacturer
Output SPL at 10 Hz	99.9 dB
Output SPL at 12.5 Hz	102.3 dB
Output SPL at 15 Hz	108.4 dB
Output SPL at 20 Hz	116.6 dB
Output SPL at 25 Hz	120.5 dB
Output SPL at 31.5 Hz	121.2 dB
Output SPL at 40 Hz	125.0 dB
Output SPL at 50 Hz	127.2 dB
Output SPL at 63 Hz	126.5 dB
Output SPL at 80 Hz	126.6 dB
Output SPL at 100 Hz	127.6 dB
Warranty	3
Weight	145.1 lbs (65.8 kg)

• Links
  • Funk Audio Ultra 21.0LX Website
• Reviews, Comparisons and Sound Samples
  • These figures are manufacturer-specified rather than independently measured.
• Head-to-Head Comparisons
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