Monoprice Monolith 16 THX Ultra vs Monoprice Monolith M-15 V2

Last updated: September 17, 2026

Short answer: the Monoprice Monolith 16 THX Ultra. It ranks #18 of 110 subwoofers by sound quality, rated 4.4/5, at $2300. The Monoprice Monolith M-15 V2 ranks #64, rated 4.2/5, at $1500, $800 cheaper, which does not close the gap in sound quality.

Monoprice Monolith 16 THX Ultra vs Monoprice Monolith M-15 V2

What the Monoprice Monolith 16 THX Ultra gets right: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked. The catch: Heavy at 78 kg (172 lbs) and ported design can interact with room acoustics.

Buy the Monoprice Monolith 16 THX Ultra. It is rated higher for sound quality, and the $800 you would save on the Monoprice Monolith M-15 V2 does not close the gap.

Want more options? Browse the full Subwoofers rankings.

Specifications Side By Side

Monoprice Monolith 16 THX Ultra Monoprice Monolith M-15 V2
Price$2,300$1,500 Discontinued
Ranked#18 of 110 in Large Home Subwoofers (Over 75 lbs)#64 of 110 in Large Home Subwoofers (Over 75 lbs)
Enclosureported, frontported, front
Output SPL at 15 Hz107.3 dB106.3 dB
Output SPL at 20 Hz118.4 dB112.6 dB
Output SPL at 25 Hz123.3 dB116.6 dB
Output SPL at 31.5 Hz125.1 dB119.5 dB
Output SPL at 40 Hz126.3 dB120.9 dB
Output SPL at 50 Hz126.5 dB120.6 dB
Output SPL at 63 Hz126.6 dB120.0 dB
Output SPL at 80 Hz126.8 dB118.7 dB
Output SPL at 100 Hz127.2 dB120.1 dB
Output SPL at 125 Hz127.6 dB120.2 dB
CEA-2010-A Average (40-80Hz)126.5 dB120.0 dB
Dimensions25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm)28.7"H x 17.7"W x 26.8"D (729.0 x 449.6 x 680.7 mm)
Weight171.5 lbs (77.8 kg)132.9 lbs (60.3 kg)
Warranty55
Cabinet Colorblackblack
CountryUnited StatesUnited States
Measurement SourceAudioholicsManufacturer
Drivers16" (406mm) driver15" (381mm) driver
InputsXLR, RCA, XLR outXLR, RCA
XLR InputYesYes
RCA InputYesYes
TRS InputNoNo
Optical InputNoNo
Coaxial InputNoNo
USB InputNoNo
HDMI InputNoNo
AES InputNoNo
Aux InputNoNo
Output SPL at 12.5 Hz-91.0 dB
Discontinued-Yes

How Monoprice Monolith 16 THX Ultra compares with other leading options:

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

Monoprice Monolith 16 THX Ultra: $2,300 eBay

Monoprice Monolith 16 THX Ultra ranking card

Pros: 16-inch ported driver and THX Ultra certification deliver 126.5dB CEA-2010-A average at a fraction of the price of the subwoofers ranked above it.

Cons: Heavy at 78 kg and ported design can interact with room acoustics.

Notes: Product # 42031

Full Monoprice Monolith 16 THX Ultra review and specifications →

AES InputNo
Aux InputNo
CEA-2010-A Average (40-80Hz)126.5 dB
Cabinet Colorblack
Coaxial InputNo
CountryUnited States
Dimensions25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm)
Drivers16" (406mm) driver
Enclosureported, front
HDMI InputNo
InputsXLR, RCA, XLR out
Measurement SourceAudioholics
Optical InputNo
Output SPL at 15 Hz107.3 dB
Output SPL at 20 Hz118.4 dB
Output SPL at 25 Hz123.3 dB
Output SPL at 31.5 Hz125.1 dB
Output SPL at 40 Hz126.3 dB
Output SPL at 50 Hz126.5 dB
Output SPL at 63 Hz126.6 dB
Output SPL at 80 Hz126.8 dB
Output SPL at 100 Hz127.2 dB
Output SPL at 125 Hz127.6 dB
RCA InputYes
TRS InputNo
USB InputNo
Warranty5
Weight171.5 lbs (77.8 kg)
XLR InputYes
Search eBay for Monoprice Monolith 16 THX Ultra →

Monoprice Monolith M-15 V2: $1,500 Discontinued eBay

Monoprice Monolith M-15 V2 ranking card

Pros: Published CEA-2010 specifications list 112.6 dB at 20 Hz and 120.0 dB through 40-80 Hz. Its front-ported 15-inch design has substantial deep-bass and midbass headroom for cinema playback.

Cons: Discontinued and no longer sold new. At 60.3 kg and 729.0H x 449.6W x 680.7D mm, it needs committed floor space and careful room integration. Discontinued.

Notes: Product # 42851

Full Monoprice Monolith M-15 V2 review and specifications →

AES InputNo
Aux InputNo
CEA-2010-A Average (40-80Hz)120.0 dB
Cabinet Colorblack
Coaxial InputNo
CountryUnited States
Dimensions28.7"H x 17.7"W x 26.8"D (729.0 x 449.6 x 680.7 mm)
DiscontinuedYes
Drivers15" (381mm) driver
Enclosureported, front
HDMI InputNo
InputsXLR, RCA
Measurement SourceManufacturer
Optical InputNo
Output SPL at 12.5 Hz91.0 dB
Output SPL at 15 Hz106.3 dB
Output SPL at 20 Hz112.6 dB
Output SPL at 25 Hz116.6 dB
Output SPL at 31.5 Hz119.5 dB
Output SPL at 40 Hz120.9 dB
Output SPL at 50 Hz120.6 dB
Output SPL at 63 Hz120.0 dB
Output SPL at 80 Hz118.7 dB
Output SPL at 100 Hz120.1 dB
Output SPL at 125 Hz120.2 dB
RCA InputYes
TRS InputNo
USB InputNo
Warranty5
Weight132.9 lbs (60.3 kg)
XLR InputYes
Search eBay for Monoprice Monolith M-15 V2 →