Monoprice Monolith M15-S Review: Rated 4.1/5

Last updated: October 21, 2026

The Monoprice Monolith M15-S is rated 4.1/5 for sound quality, #88 of 143 Large Home Subwoofers (Over 75 lbs). See all Subwoofers rankings for every top pick.

Monoprice Monolith M15-S · Editor's rating 4.1/5, ranked #88 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.

As an eBay Partner, we may be compensated if you make a purchase.

Brand: Monoprice

#88 Monoprice Monolith M15-S: $999 Discontinued eBay

Same family: the Monoprice Monolith M10-S (smaller subwoofer, rated 3.4/5) and the Monoprice Monolith M12-S (smaller subwoofer, ranked lower, rated 3.7/5).

Pros: A sealed 15 inch subwoofer with plenty of clean output for film bass in a large room, now discontinued but worth buying used. Published CEA-2010 specifications list 105.6 dB at 20 Hz and 119.0 dB through 40-80 Hz. The sealed enclosure with 15” (381mm) driver has the headroom for demanding film bass in a large room.

Cons: The 596.9H x 424.2W x 500.4D mm cabinet and 36.3 kg mass make this a serious placement and moving commitment. A sealed cabinet still needs careful placement and calibration to avoid room-mode peaks. Discontinued.

Notes: Product # 35141

Is the Monoprice Monolith M15-S right for you?

Skip it if

  • you need to move it often (36 kg each).
  • you want to buy it new: it is discontinued.
Released2019 (7 years ago)
CEA-2010-A Average (40-80Hz)119.0 dB
CountryUnited States
Dimensions23.5”H x 16.7”W x 19.7”D (596.9 x 424.2 x 500.4 mm)
Drivers15” (381mm) driver
Enclosuresealed
Measurement SourceManufacturer
Output SPL at 15 Hz100.1 dB
Output SPL at 20 Hz105.6 dB
Output SPL at 25 Hz111.2 dB
Output SPL at 31.5 Hz115.2 dB
Output SPL at 40 Hz118.4 dB
Output SPL at 50 Hz119.3 dB
Output SPL at 63 Hz119.6 dB
Output SPL at 80 Hz118.9 dB
Output SPL at 100 Hz119.1 dB
Output SPL at 125 Hz118.9 dB
Warranty5
Weight80 lbs (36.3 kg)
Search eBay for Monoprice Monolith M15-S →

Head-to-Head Comparisons

16 comparisons

More Monoprice speakers →