Short answer: the HSU Research ULS-15 MK2 has been measured and ranked among subwoofers; the Sonos Sub 4 has not been independently measured yet, so until it is, this comes down to features and price.
What the Sonos Sub 4 offers: Two force-cancelling drivers face each other to cut cabinet buzz and rattle, and Sonos rates bass down to 25Hz.
What the HSU Research ULS-15 MK2 brings: Sealed design delivers tight, accurate bass with low bloat.
On paper: The Sonos Sub 4 is rated down to 25Hz against 200Hz, though makers quote these at different tolerances.
Price: the Sonos Sub 4 lists at $899 and the HSU Research ULS-15 MK2 at $999.
Buy the HSU Research ULS-15 MK2 if you want a speaker whose sound quality has been measured and ranked.
Buy the Sonos Sub 4 if you want deeper rated bass, and you can wait for measurements to confirm how it sounds.
Want more options? Browse the full Subwoofers rankings.
Specifications Side By Side
| Sonos Sub 4 | HSU Research ULS-15 MK2 | |
|---|---|---|
| Price | $899.00 | $1,035 |
| Ranked | - | #3 of 145 in Medium Home Subwoofers (30-75 lbs) |
| Enclosure | ported, force-cancelling | sealed |
| Drivers | 2x force-cancelling drivers | 15” (381mm) driver |
| Frequency Response | 25Hz extension (manufacturer specified) | 20-200Hz, ±1dB |
| Cabinet Color | black, white | black, wood |
| Country | United States | United States |
| Output SPL at 12.5 Hz | - | 93.7 dB |
| Output SPL at 15 Hz | - | 98.0 dB |
| Output SPL at 20 Hz | - | 102.4 dB |
| Output SPL at 25 Hz | - | 107.7 dB |
| Output SPL at 31.5 Hz | - | 113.4 dB |
| Output SPL at 40 Hz | - | 118.3 dB |
| Output SPL at 50 Hz | - | 120.8 dB |
| Output SPL at 63 Hz | - | 121.2 dB |
| Output SPL at 80 Hz | - | 121.1 dB |
| Output SPL at 100 Hz | - | 120.7 dB |
| Output SPL at 125 Hz | - | 120.7 dB |
| CEA-2010-A Average (40-80Hz) | - | 120.3 dB |
| Dimensions | - | 19”H x 18”W x 19.5”D (482.6 x 457.2 x 495.3 mm) |
| Weight | - | 65 lbs (29.5 kg) |
| Warranty | - | 7/2(+3) |
| Measurement Source | - | Audioholics |
| Amplifier Power | - | 600W RMS / 2000W peak |
| Crossover Frequency | - | 30-90Hz adjustable |
| Phase Control | - | 0°-180° |
| Features | - | Q control, sealed subwoofer, EQ1/EQ2 modes |
Prices on this page were last checked September 29, 2026 at 3:43 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
Sonos Sub 4: $899.00 Amazon eBay
Older model: the Sonos Sub (Gen 1) (rated 3.7/5).
Pros: Two force-cancelling drivers face each other to cut cabinet buzz and rattle, and Sonos rates bass down to 25Hz. Connects to a Sonos soundbar or speaker over Wi-Fi, so it can go anywhere with a power outlet, and sets up from the Sonos app.
Cons: No independent measurements yet, so its output can’t be compared with ranked subwoofers. It only works with Sonos soundbars and speakers, with no line-level input for any other system.
Full Sonos Sub 4 review and specifications →
| Cabinet Color | black, white |
|---|---|
| Country | United States |
| Drivers | 2x force-cancelling drivers |
| Enclosure | ported, force-cancelling |
| Frequency Response | 25Hz extension (manufacturer specified) |
- Links
- Reviews, Comparisons and Sound Samples
- These figures are manufacturer-specified rather than independently measured.
- Head-to-Head Comparisons
HSU Research ULS-15 MK2: $1,035 HSU Research eBay
Pros: Sealed design delivers tight, accurate bass with low bloat. 600W BASH amplifier. 30% less expensive and 20 lbs lighter than predecessor. Easy integration with Q and EQ controls. Great value in the 15” sub market.
Notes: Price includes shipping
Full HSU Research ULS-15 MK2 review and specifications →
| Amplifier Power | 600W RMS / 2000W peak |
|---|---|
| CEA-2010-A Average (40-80Hz) | 120.3 dB |
| Cabinet Color | black, wood |
| Country | United States |
| Crossover Frequency | 30-90Hz adjustable |
| Dimensions | 19”H x 18”W x 19.5”D (482.6 x 457.2 x 495.3 mm) |
| Drivers | 15” (381mm) driver |
| Enclosure | sealed |
| Features | Q control, sealed subwoofer, EQ1/EQ2 modes |
| Frequency Response | 20-200Hz, ±1dB |
| Measurement Source | Audioholics |
| Output SPL at 12.5 Hz | 93.7 dB |
| Output SPL at 15 Hz | 98.0 dB |
| Output SPL at 20 Hz | 102.4 dB |
| Output SPL at 25 Hz | 107.7 dB |
| Output SPL at 31.5 Hz | 113.4 dB |
| Output SPL at 40 Hz | 118.3 dB |
| Output SPL at 50 Hz | 120.8 dB |
| Output SPL at 63 Hz | 121.2 dB |
| Output SPL at 80 Hz | 121.1 dB |
| Output SPL at 100 Hz | 120.7 dB |
| Output SPL at 125 Hz | 120.7 dB |
| Phase Control | 0°-180° |
| Warranty | 7/2(+3) |
| Weight | 65 lbs (29.5 kg) |
- Links
- Reviews, Comparisons and Sound Samples
- Independently measured by Audioholics; the published figures above come from this ASR subwoofer measurement thread.
- Head-to-Head Comparisons
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- HSU Research ULS-15 MK2 vs Monoprice SW-15
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- See all 22 comparisons