Monoprice Monolith 13 THX Ultra Review: Rated 4.2/5

Last updated: October 21, 2026

The Monoprice Monolith 13 THX Ultra is rated 4.2/5 for sound quality, #63 of 143 Large Home Subwoofers (Over 75 lbs). See all Subwoofers rankings for every top pick.

Monoprice Monolith 13 THX Ultra · Editor's rating 4.2/5, ranked #63 of 143 Large Home Subwoofers (Over 75 lbs)

Prices on this page were last checked October 28, 2026 at 1:06 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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Brand: Monoprice

#63 Monoprice Monolith 13 THX Ultra: $1,700 Discontinued eBay

Same family: the Monoprice Monolith 12 THX Ultra (smaller subwoofer, ranked lower, rated 3.8/5), the Monoprice Monolith 15 THX Ultra (larger subwoofer, ranked lower, rated 4.2/5) and the Monoprice Monolith 16 THX Ultra (larger subwoofer, ranked higher, rated 4.4/5). See every Monoprice Monolith generation.

Pros: A THX Ultra certified 13 inch ported subwoofer with deep, strong bass for large rooms at a good price used. 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. Discontinued.

Notes: Product # 41496

Is the Monoprice Monolith 13 THX Ultra right for you?

Skip it if

  • you need to move it often (70 kg each).
  • you want to buy it new: it is discontinued.
ReleasedAug 2021 (5 years ago)
AES InputNo
Aux InputNo
CEA-2010-A Average (40-80Hz)121.1 dB
Cabinet Colorblack
Coaxial InputNo
CountryUnited States
Dimensions23.8”H x 20.3”W x 29.1”D (604.5 x 515.6 x 739.1 mm)
Drivers13” (330mm) driver
Enclosureported, front
HDMI InputNo
InputsXLR (stereo balanced), RCA (stereo/mono)
Measurement SourceAudioholics
Optical InputNo
Output SPL at 12.5 Hz94.0 dB
Output SPL at 15 Hz109.1 dB
Output SPL at 20 Hz115.0 dB
Output SPL at 25 Hz118.0 dB
Output SPL at 31.5 Hz119.5 dB
Output SPL at 40 Hz120.3 dB
Output SPL at 50 Hz120.7 dB
Output SPL at 63 Hz121.4 dB
Output SPL at 80 Hz122.1 dB
Output SPL at 100 Hz122.7 dB
Output SPL at 125 Hz123.8 dB
RCA InputYes
TRS InputNo
USB InputNo
Warranty5
Weight153.2 lbs (69.5 kg)
XLR InputYes
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