Short answer: both are discontinued, so this only matters if you are buying used. Used, the Andover Audio SpinSub is the better pick: it ranks #40 of 73 subwoofers by sound quality (rated 3.3/5), against #66 (rated 2.7/5) for the Monoprice Monolith 8 THX Certified. If you want one new, the Edifier T5s ranks #2 at $199.99.
The Andover Audio SpinSub is the better-sounding option. A discontinued compact ported subwoofer with two 6.5 inch drivers, adding bass support without a full size cabinet. The tradeoff: Without a published 20 Hz output result, deep-bass capability is less certain than its midbass figure.
What the Monoprice Monolith 8 THX Certified does well: A compact THX certified 8 inch subwoofer with selectable modes, sized for a small room or satellite system. Watch for: Deep-bass output is modest for a home-theater subwoofer, falling to 72.9dB at 20Hz and 86.1dB at 25Hz.
Buy the Andover Audio SpinSub only if you find one used in good condition; both are discontinued, and it is the better rated of the two. For a new speaker, start with the Edifier T5s instead.
Still deciding? The full Subwoofers rankings cover every ranked option.
Prices on this page were last checked November 14, 2026 at 6:17 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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Specifications Side By Side
| Andover Audio SpinSub | Monoprice Monolith 8 THX Certified | |
|---|---|---|
| Price | $350 Discontinued | $350 Discontinued |
| Ranked | #40 of 73 in Small Home Subwoofers (Under 30 lbs) | #66 of 73 in Small Home Subwoofers (Under 30 lbs) |
| Warranty | 2 | - |
| Enclosure | ported | ported |
| Output SPL at 25 Hz | 91.2 dB | 86.1 dB |
| Output SPL at 31.5 Hz | 98.6 dB | 93.2 dB |
| Output SPL at 40 Hz | 104.3 dB | 96.9 dB |
| Output SPL at 50 Hz | 105.5 dB | 99.3 dB |
| Output SPL at 63 Hz | 110.3 dB | 100.7 dB |
| Output SPL at 80 Hz | 109.6 dB | 101.6 dB |
| CEA-2010-A Average (40-80Hz) | 107.4 dB | 99.6 dB |
| Dimensions | 14.2”H x 11.3”W x 12.7”D (361.9 x 285.8 x 323.8 mm) | 12.6”H x 13.5”W x 12.6”D (319.8 x 342.9 x 319.8 mm) |
| Weight | 20.9 lbs (9.5 kg) | 19.8 lbs (9.0 kg) |
| Cabinet Color | black, grey | black |
| Country | United States | United States |
| Measurement Source | Brent Butterworth | ErinsAudioCorner |
| Drivers | 2x 6.5” (165mm) driver | 8” (203mm) driver |
| Output SPL at 20 Hz | - | 72.9 dB |
| Output SPL at 100 Hz | - | 101.9 dB |
Where the Ratings Come From
- Andover Audio SpinSub: manufacturer specifications and listening comparisons; no independent measurement has been published yet.
- Monoprice Monolith 8 THX Certified: reviews by Erin’s Audio Corner.
This comparison is generated from the ratings, specifications and measurements on each product’s own page, and it updates when that data changes. How we rank explains how each rating is decided.
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