JTR Speakers Captivator S2 vs Monoprice Monolith M-215

Short answer: the JTR Speakers Captivator S2. It ranks #9 of 110 subwoofers by sound quality, rated 4.5/5, at $3995. The Monoprice Monolith M-215 ranks #23, rated 4.4/5, at $2999.99, $995.01 cheaper, not enough of a saving to outweigh the sound-quality gap.

Buy the JTR Speakers Captivator S2. It is rated higher for sound quality, and the $995.01 saving on the Monoprice Monolith M-215 is not enough to make up the difference.

Want more options? Browse the full Subwoofers rankings.

Specifications Side By Side

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Prices on this page were last checked September 23, 2026 at 11:24 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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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 →

AES Input	No
Aux Input	No
CEA-2010-A Average (40-80Hz)	129.4 dB
Coaxial Input	No
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
HDMI Input	No
Inputs	XLR (balanced), RCA
Measurement Source	Data-bass
Optical Input	No
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
RCA Input	Yes
TRS Input	No
USB Input	No
Warranty	5/3
Weight	220 lbs (99.8 kg)
XLR Input	Yes

• 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.
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Monoprice Monolith M-215: $2999.99 Monoprice eBay

Pros: Independent CEA-2010 testing records 118.9 dB at 20 Hz and 125.9 dB through 40-80 Hz. The ported, front enclosure with 2x 15” (381mm) drivers has the headroom for demanding film bass in a large room.

Cons: The 1074.4H x 508.0W x 701.0D mm cabinet and 98.0 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.

Notes: Product # 38543

Full Monoprice Monolith M-215 review and specifications →

CEA-2010-A Average (40-80Hz)	125.9 dB
Cabinet Color	black
Country	United States
Dimensions	42.3"H x 20"W x 27.6"D (1074.4 x 508.0 x 701.0 mm)
Drivers	2x 15" (381mm) drivers
Enclosure	ported, front
Measurement Source	Brent Butterworth
Output SPL at 12.5 Hz	103.9 dB
Output SPL at 15 Hz	113.1 dB
Output SPL at 20 Hz	118.9 dB
Output SPL at 25 Hz	122.6 dB
Output SPL at 31.5 Hz	125.2 dB
Output SPL at 40 Hz	126.4 dB
Output SPL at 50 Hz	126.1 dB
Output SPL at 63 Hz	125.6 dB
Output SPL at 80 Hz	125.6 dB
Output SPL at 100 Hz	125.7 dB
Output SPL at 125 Hz	126.3 dB
Warranty	5
Weight	216.1 lbs (98.0 kg)

• Links
  • Monoprice Monolith M-215 Website
• Reviews, Comparisons and Sound Samples
  • Independently measured by Brent Butterworth; the published figures above come from this ASR subwoofer measurement thread.
• Head-to-Head Comparisons
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