Monoprice Monolith 16 THX Ultra vs Monoprice Monolith M-215

Last updated: August 9, 2026

Short answer: the Monoprice Monolith 16 THX Ultra. It ranks #13 of 97 subwoofers at $2300; the Monoprice Monolith M-215 ranks #18 and costs $2500, so there is not much of a tradeoff to weigh.

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 and ported design can interact with room acoustics.

Buy the Monoprice Monolith 16 THX Ultra if the ranking matters more than the price. Buy the Monoprice Monolith M-215 if the price matters more than the ranking.

Specifications Side By Side

Monoprice Monolith 16 THX Ultra Monoprice Monolith M-215
Price$2,300$2,500
Ranked#13 of 97 in Large Powered Home Subwoofers (Over 75 lbs)#18 of 97 in Large Powered 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 22.0"W x 28.1"D (650.2 x 558.8 x 713.7 mm)42.3"H x 20.0"W x 27.6"D (1074.4 x 508.0 x 701.0 mm)
Weight171.5 lbs / 77.8 kg216.1 lbs / 98.0 kg
Warranty55
Cabinet Colorblackblack
CountryUnited StatesUnited States
Measurement SourceAudioholicsBrent Butterworth
Drivers16" (406mm) driver2x 15" (381mm) drivers
Output SPL at 12.5 Hz-103.9 dB

The Two Speakers In Full

Monoprice Monolith 16 THX Ultra: $2,300

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

CEA-2010-A Average (40-80Hz)126.5 dB
Cabinet Colorblack
CountryUnited States
Dimensions25.6"H x 22.0"W x 28.1"D (650.2 x 558.8 x 713.7 mm)
Drivers16" (406mm) driver
Enclosureported, front
Measurement SourceAudioholics
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
Warranty5
Weight171.5 lbs / 77.8 kg

Monoprice Monolith M-215: $2,500

Monoprice Monolith M-215 ranking card

Notes: Product # 38543

CEA-2010-A Average (40-80Hz)125.9 dB
Cabinet Colorblack
CountryUnited States
Dimensions42.3"H x 20.0"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

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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.