JTR Speakers Captivator S2 vs Monoprice Monolith 13 THX Ultra

Short answer: the JTR Speakers Captivator S2 for better sound quality, the Monoprice Monolith 13 THX Ultra for the lower price. The JTR Speakers Captivator S2 ranks #9 of 110 subwoofers at $3995. The Monoprice Monolith 13 THX Ultra ranks #56 at $1700, $2295 cheaper.

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 Monoprice Monolith 13 THX Ultra offers: Independent CEA-2010 testing records 115.0 dB at 20 Hz and 121.1 dB through 40-80 Hz. The ported, front enclosure with 13” (330mm) driver has the headroom for demanding film bass in a large room. Watch for: The 604.5H x 515.6W x 739.1D mm cabinet and 69.5 kg mass make this a serious placement and moving commitment. Ported output does not solve room modes, so careful placement and calibration remain essential.

Buy the JTR Speakers Captivator S2 if sound quality is the priority over the price, or the Monoprice Monolith 13 THX Ultra if the price is the priority over sound quality.

Still deciding? The full Subwoofers rankings cover every ranked option.

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 Funk Audio Custom 21.0
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Monoprice Monolith 13 THX Ultra: $1,700 eBay

Pros: Independent CEA-2010 testing records 115.0 dB at 20 Hz and 121.1 dB through 40-80 Hz. The ported, front enclosure with 13” (330mm) driver has the headroom for demanding film bass in a large room.

Cons: The 604.5H x 515.6W x 739.1D mm cabinet and 69.5 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 # 41496

Full Monoprice Monolith 13 THX Ultra review and specifications →

CEA-2010-A Average (40-80Hz)	121.1 dB
Cabinet Color	black
Country	United States
Dimensions	23.8"H x 20.3"W x 29.1"D (604.5 x 515.6 x 739.1 mm)
Drivers	13" (330mm) driver
Enclosure	ported, front
Measurement Source	Audioholics
Output SPL at 12.5 Hz	94.0 dB
Output SPL at 15 Hz	109.1 dB
Output SPL at 20 Hz	115.0 dB
Output SPL at 25 Hz	118.0 dB
Output SPL at 31.5 Hz	119.5 dB
Output SPL at 40 Hz	120.3 dB
Output SPL at 50 Hz	120.7 dB
Output SPL at 63 Hz	121.4 dB
Output SPL at 80 Hz	122.1 dB
Output SPL at 100 Hz	122.7 dB
Output SPL at 125 Hz	123.8 dB
Warranty	5
Weight	153.2 lbs (69.5 kg)

• Links
  • Monoprice Monolith 13 THX Ultra Website
• Reviews, Comparisons and Sound Samples
  • Independently measured by Audioholics; the published figures above come from this ASR subwoofer measurement thread.
• Head-to-Head Comparisons
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