Short answer: the Dayton Audio MKSX4. It ranks #1 of 2 subwoofers at $144.98; the BG Radia BGX-S6B ranks #2 and costs $189, so there is not much of a tradeoff to weigh.
On the BG Radia BGX-S6B side: Six 4-inch drivers in a low-profile in-wall panel deliver 102.1dB CEA-2010-A average. The tradeoff: In-wall installation required, limited 102.1 dB output, passive design, and compact 7.3 kg constraints.
The case for the Dayton Audio MKSX4: Four 4-inch drivers in a low-profile (under 8-inch) cabinet deliver 106.2dB CEA-2010-A average. The tradeoff: Budget-tier output at 106.2 dB, four small 4-inch drivers, ported room dependency, and $145 price point.
One note: the BG Radia BGX-S6B is discontinued, but it still ranks #2 of 2 subwoofers, ahead of most of what is still sold new, so it is worth considering used.
Buy the BG Radia BGX-S6B if the price matters more than the ranking. Buy the Dayton Audio MKSX4 if the ranking matters more than the price.
Specifications Side By Side
| BG Radia BGX-S6B | Dayton Audio MKSX4 | |
|---|---|---|
| Price | $189 Discontinued | $144.98 |
| Ranked | #2 of 2 in Small Passive Home Subwoofers (Under 30 lbs) | #1 of 2 in Small Passive Home Subwoofers (Under 30 lbs) |
| Enclosure | in-wall | ported, rear |
| Passive | Yes | Yes |
| Output SPL at 20 Hz | 82.3 dB | - |
| Output SPL at 25 Hz | 82.3 dB | - |
| Output SPL at 31.5 Hz | 82.3 dB | 78.7 dB |
| Output SPL at 40 Hz | 102.1 dB | 95.4 dB |
| Output SPL at 50 Hz | 102.1 dB | 106.8 dB |
| Output SPL at 63 Hz | 102.1 dB | 110.3 dB |
| CEA-2010-A Average (40-80Hz) | 102.1 dB (avg of 3/4 bands) | 106.2 dB |
| Dimensions | 14.0"H x 14.0"W x 3.75"D (355.6 x 355.6 x 95.2 mm) | 16.0"H x 5.9"W x 14.0"D (406.4 x 149.9 x 355.6 mm) |
| Weight | 16.1 lbs / 7.3 kg | 26.9 lbs / 12.2 kg |
| Measurement Source | Brent Butterworth | Brent Butterworth |
| Discontinued | Yes | - |
| Drivers | 6x 4" (102mm) driver | 4x 4" (102mm) driver |
| Output SPL at 80 Hz | - | 112.3 dB |
| Warranty | - | 5 |
| Cabinet Color | - | black |
| Country | - | United States |
The Two Speakers In Full
BG Radia BGX-S6B: $189 Discontinued
Pros: Six 4-inch drivers in a low-profile in-wall panel deliver 102.1dB CEA-2010-A average, a flush-mount alternative for rooms where a cabinet subwoofer won’t fit.
Cons: In-wall installation required, limited 102.1 dB output, passive design, and compact 7.3 kg constraints. Discontinued.
Notes: low profile (<8in)
| CEA-2010-A Average (40-80Hz) | 102.1 dB (avg of 3/4 bands) |
|---|---|
| Dimensions | 14.0"H x 14.0"W x 3.75"D (355.6 x 355.6 x 95.2 mm) |
| Discontinued | Yes |
| Drivers | 6x 4" (102mm) driver |
| Enclosure | in-wall |
| Measurement Source | Brent Butterworth |
| Output SPL at 20 Hz | 82.3 dB |
| Output SPL at 25 Hz | 82.3 dB |
| Output SPL at 31.5 Hz | 82.3 dB |
| Output SPL at 40 Hz | 102.1 dB |
| Output SPL at 50 Hz | 102.1 dB |
| Output SPL at 63 Hz | 102.1 dB |
| Passive | Yes |
| Weight | 16.1 lbs / 7.3 kg |
- Buy Used
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Dayton Audio MKSX4: $144.98 Amazon
Pros: Four 4-inch drivers in a low-profile (under 8-inch) cabinet deliver 106.2dB CEA-2010-A average, the best output-per-dollar of any passive subwoofer tested.
Cons: Budget-tier output at 106.2 dB, four small 4-inch drivers, ported room dependency, and $145 price point.
Notes: low profile (<8in)
| CEA-2010-A Average (40-80Hz) | 106.2 dB |
|---|---|
| Cabinet Color | black |
| Country | United States |
| Dimensions | 16.0"H x 5.9"W x 14.0"D (406.4 x 149.9 x 355.6 mm) |
| Drivers | 4x 4" (102mm) driver |
| Enclosure | ported, rear |
| Measurement Source | Brent Butterworth |
| Output SPL at 31.5 Hz | 78.7 dB |
| Output SPL at 40 Hz | 95.4 dB |
| Output SPL at 50 Hz | 106.8 dB |
| Output SPL at 63 Hz | 110.3 dB |
| Output SPL at 80 Hz | 112.3 dB |
| Passive | Yes |
| Warranty | 5 |
| Weight | 26.9 lbs / 12.2 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.