Monoprice Monolith 16 THX Ultra vs Monoprice Monolith M-215

Last updated: September 17, 2026

Short answer: the Monoprice Monolith 16 THX Ultra. Both are rated 4.4/5 for sound quality (#18 and #23 of 110 subwoofers), and the Monoprice Monolith 16 THX Ultra costs $2300 against $2999.99 for the Monoprice Monolith M-215, with sound quality a draw, the lower price decides it.

Monoprice Monolith 16 THX Ultra vs Monoprice Monolith M-215

The case for the Monoprice Monolith 16 THX Ultra: 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. Set against that: Heavy at 78 kg (172 lbs) and ported design can interact with room acoustics.

Buy the Monoprice Monolith 16 THX Ultra. Both are rated the same for sound quality, and it costs $699.99 less than the Monoprice Monolith M-215.

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

Buy the Monoprice Monolith M-215 at Monoprice ($2999.99) →

Specifications Side By Side

Monoprice Monolith 16 THX Ultra Monoprice Monolith M-215
Price$2,300$2999.99
Ranked#18 of 110 in Large Home Subwoofers (Over 75 lbs)#23 of 110 in Large Home Subwoofers (Over 75 lbs)
Enclosureported, frontported, front
Output SPL at 15 Hz107.3 dB113.1 dB
Output SPL at 20 Hz118.4 dB118.9 dB
Output SPL at 25 Hz123.3 dB122.6 dB
Output SPL at 31.5 Hz125.1 dB125.2 dB
Output SPL at 40 Hz126.3 dB126.4 dB
Output SPL at 50 Hz126.5 dB126.1 dB
Output SPL at 63 Hz126.6 dB125.6 dB
Output SPL at 80 Hz126.8 dB125.6 dB
Output SPL at 100 Hz127.2 dB125.7 dB
Output SPL at 125 Hz127.6 dB126.3 dB
CEA-2010-A Average (40-80Hz)126.5 dB125.9 dB
Dimensions25.6"H x 22"W x 28.1"D (650.2 x 558.8 x 713.7 mm)42.3"H x 20"W x 27.6"D (1074.4 x 508.0 x 701.0 mm)
Weight171.5 lbs (77.8 kg)216.1 lbs (98.0 kg)
Warranty55
Cabinet Colorblackblack
CountryUnited StatesUnited States
Measurement SourceAudioholicsBrent Butterworth
Drivers16" (406mm) driver2x 15" (381mm) drivers
InputsXLR, RCA, XLR out-
XLR InputYes-
RCA InputYes-
TRS InputNo-
Optical InputNo-
Coaxial InputNo-
USB InputNo-
HDMI InputNo-
AES InputNo-
Aux InputNo-
Output SPL at 12.5 Hz-103.9 dB
Buy the Monoprice Monolith M-215 at Monoprice ($2999.99) →

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
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Monoprice Monolith M-215: $2999.99 Monoprice eBay

Monoprice Monolith M-215 ranking card

Pros: Independent CEA-2010 testing records 118.9 dB at 20 Hz and 125.9 dB through 40-80 Hz. The ported, front enclosure with 2x 15” (381mm) drivers has the headroom for demanding film bass in a large room.

Cons: The 1074.4H x 508.0W x 701.0D mm cabinet and 98.0 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 # 38543

Full Monoprice Monolith M-215 review and specifications →

CEA-2010-A Average (40-80Hz)125.9 dB
Cabinet Colorblack
CountryUnited States
Dimensions42.3"H x 20"W x 27.6"D (1074.4 x 508.0 x 701.0 mm)
Drivers2x 15" (381mm) drivers
Enclosureported, front
Measurement SourceBrent Butterworth
Output SPL at 12.5 Hz103.9 dB
Output SPL at 15 Hz113.1 dB
Output SPL at 20 Hz118.9 dB
Output SPL at 25 Hz122.6 dB
Output SPL at 31.5 Hz125.2 dB
Output SPL at 40 Hz126.4 dB
Output SPL at 50 Hz126.1 dB
Output SPL at 63 Hz125.6 dB
Output SPL at 80 Hz125.6 dB
Output SPL at 100 Hz125.7 dB
Output SPL at 125 Hz126.3 dB
Warranty5
Weight216.1 lbs (98.0 kg)
Check current price at Monoprice ($2999.99) →Search eBay for Monoprice Monolith M-215 →