The Monoprice Monolith 15 THX Ultra ranks #59 out of 110 total Large Home Subwoofers (Over 75 lbs) for sound quality. See all Subwoofers rankings for every top pick.
Brand: Monoprice
Prices on this page were last checked September 14, 2026 at 1:47 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.
#59 Monoprice Monolith 15 THX Ultra: $1999 eBay
Pros: Independent CEA-2010 testing records 110.0 dB at 20 Hz and 120.5 dB through 40-80 Hz. The ported, front enclosure with 15” (381mm) driver has the headroom for demanding film bass in a large room.
Cons: The 680.7H x 449.6W x 701.0D mm cabinet and 58.3 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 # 24458
How it compares: Just above it: Epik Subwoofers Empire - $4996 more. Just below it: Klipsch RP-1600SW - $399 cheaper.
| CEA-2010-A Average (40-80Hz) | 120.5 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 26.8"H x 17.7"W x 27.6"D (680.7 x 449.6 x 701.0 mm) |
| Drivers | 15" (381mm) driver |
| Enclosure | ported, front |
| Measurement Source | ErinsAudioCorner |
| Output SPL at 12.5 Hz | 90.0 dB |
| Output SPL at 15 Hz | 100.8 dB |
| Output SPL at 20 Hz | 110.0 dB |
| Output SPL at 25 Hz | 115.6 dB |
| Output SPL at 31.5 Hz | 118.0 dB |
| Output SPL at 40 Hz | 122.0 dB |
| Output SPL at 50 Hz | 121.0 dB |
| Output SPL at 63 Hz | 120.0 dB |
| Output SPL at 80 Hz | 119.0 dB |
| Output SPL at 100 Hz | 119.0 dB |
| Output SPL at 125 Hz | 118.0 dB |
| Warranty | 5 |
| Weight | 128.5 lbs (58.3 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by ErinsAudioCorner; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons