Short answer: the Monoprice Monolith 8 THX Certified. It ranks #37 of 42 subwoofers by sound quality at $350; the Paradigm Millenia CT ranks #38 and costs $499, so there is not much of a tradeoff to weigh.
What the Paradigm Millenia CT offers: Independent CEA-2010 testing records 99.0 dB (avg of 3/4 bands) through 40-80 Hz. The subwoofer enclosure with 8” (203mm) driver is intended to add useful bass support without a full-size cabinet. Watch for: Without a published 20 Hz output result, deep-bass capability is less certain than its midbass figure. The 400.0H x 127.0W x 355.6D mm cabinet and 5.7 kg mass still need careful placement and calibration.
What the Monoprice Monolith 8 THX Certified offers: A compact 9kg, ported 8-inch subwoofer with THX certification that can suit a small room or satellite-based system without taking much floor space. Measured output is useful through the upper bass: 99.3dB at 50Hz, 100.7dB at 63Hz and 101.6dB at 80Hz. Its selectable THX/EQ modes provide a more controlled option for music than the extended setting. Watch for: Deep-bass output is modest for a home-theater subwoofer, falling to 72.9dB at 20Hz and 86.1dB at 25Hz. It will not deliver the infrasonic impact or room-filling output of a larger model, and the manufacturer lists it as out of stock. Choose it for compactness and moderate listening levels, not for demanding cinema effects.
Buy the Monoprice Monolith 8 THX Certified. It ranks higher for sound quality than the Paradigm Millenia CT and costs less, which settles it without a real tradeoff to make.
If sound quality matters at all to you, skip both of these and look higher up the 42 subwoofers instead.
Specifications Side By Side
| Paradigm Millenia CT | Monoprice Monolith 8 THX Certified | |
|---|---|---|
| Price | $499 | $350 |
| Ranked | #38 of 42 in Small Powered Home Subwoofers (Under 30 lbs) | #37 of 42 in Small Powered Home Subwoofers (Under 30 lbs) |
| Output SPL at 25 Hz | 67.8 dB | 86.1 dB |
| Output SPL at 31.5 Hz | 80.0 dB | 93.2 dB |
| Output SPL at 40 Hz | 90.4 dB | 96.9 dB |
| Output SPL at 50 Hz | 100.0 dB | 99.3 dB |
| Output SPL at 63 Hz | 106.7 dB | 100.7 dB |
| CEA-2010-A Average (40-80Hz) | 99.0 dB (avg of 3/4 bands) | 99.6 dB |
| Dimensions | 15.7"H x 5"W x 14"D (400.0 x 127.0 x 355.6 mm) | 12.6"H x 13.5"W x 12.6"D (319.8 x 342.9 x 319.8 mm) |
| Weight | 12.6 lbs / 5.7 kg | 19.8 lbs / 9.0 kg |
| Warranty | 3 | - |
| Country | Canada | United States |
| Measurement Source | Brent Butterworth | ErinsAudioCorner |
| Drivers | 8" (203mm) driver | 8" (203mm) driver |
| Enclosure | - | ported |
| Output SPL at 20 Hz | - | 72.9 dB |
| Output SPL at 80 Hz | - | 101.6 dB |
| Output SPL at 100 Hz | - | 101.9 dB |
| Cabinet Color | - | black |
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- Andover Audio SpinSub vs Monoprice Monolith 8 THX Certified
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Prices on this page were last checked September 8, 2026 at 6:02 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
Paradigm Millenia CT: $499 eBay
Pros: Independent CEA-2010 testing records 99.0 dB (avg of 3/4 bands) through 40-80 Hz. The subwoofer enclosure with 8” (203mm) driver is intended to add useful bass support without a full-size cabinet.
Cons: Without a published 20 Hz output result, deep-bass capability is less certain than its midbass figure. The 400.0H x 127.0W x 355.6D mm cabinet and 5.7 kg mass still need careful placement and calibration.
Notes: low profile (<8in)
Full Paradigm Millenia CT review and specifications →
| CEA-2010-A Average (40-80Hz) | 99.0 dB (avg of 3/4 bands) |
|---|---|
| Country | Canada |
| Dimensions | 15.7"H x 5"W x 14"D (400.0 x 127.0 x 355.6 mm) |
| Drivers | 8" (203mm) driver |
| Measurement Source | Brent Butterworth |
| Output SPL at 25 Hz | 67.8 dB |
| Output SPL at 31.5 Hz | 80.0 dB |
| Output SPL at 40 Hz | 90.4 dB |
| Output SPL at 50 Hz | 100.0 dB |
| Output SPL at 63 Hz | 106.7 dB |
| Warranty | 3 |
| Weight | 12.6 lbs / 5.7 kg |
- Links
- Reviews, Comparisons and Sound Samples
Monoprice Monolith 8 THX Certified: $350 eBay
Pros: A compact 9kg, ported 8-inch subwoofer with THX certification that can suit a small room or satellite-based system without taking much floor space. Measured output is useful through the upper bass: 99.3dB at 50Hz, 100.7dB at 63Hz and 101.6dB at 80Hz. Its selectable THX/EQ modes provide a more controlled option for music than the extended setting.
Cons: Deep-bass output is modest for a home-theater subwoofer, falling to 72.9dB at 20Hz and 86.1dB at 25Hz. It will not deliver the infrasonic impact or room-filling output of a larger model, and the manufacturer lists it as out of stock. Choose it for compactness and moderate listening levels, not for demanding cinema effects.
Notes: Product # 41289
Full Monoprice Monolith 8 THX Certified review and specifications →
| CEA-2010-A Average (40-80Hz) | 99.6 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 12.6"H x 13.5"W x 12.6"D (319.8 x 342.9 x 319.8 mm) |
| Drivers | 8" (203mm) driver |
| Enclosure | ported |
| Measurement Source | ErinsAudioCorner |
| Output SPL at 20 Hz | 72.9 dB |
| Output SPL at 25 Hz | 86.1 dB |
| Output SPL at 31.5 Hz | 93.2 dB |
| Output SPL at 40 Hz | 96.9 dB |
| Output SPL at 50 Hz | 99.3 dB |
| Output SPL at 63 Hz | 100.7 dB |
| Output SPL at 80 Hz | 101.6 dB |
| Output SPL at 100 Hz | 101.9 dB |
| Weight | 19.8 lbs / 9.0 kg |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons