Sonos Sub 4 Review: The Wireless Sub for Sonos Systems Only

The Sonos Sub 4 is the subwoofer to buy if you own a Sonos Arc Ultra, Arc or Beam and want bass you can feel in a living room. It pairs over Wi-Fi in a few taps, Sonos rates it down to 25 Hz, and it can stand upright or lie flat under a sofa.

It only works with Sonos. There is no RCA, LFE or other wired audio input, so it cannot join an AV receiver or another brand's soundbar. If you already own a Sub (Gen 3), the upgrade is small, and owners of a Ray, Beam or Era 100 in a small room are often better served by the cheaper Sub Mini.

We did not test the Sub 4 in person. This review is built from Sonos's specs and support documents, published measurements of Sonos systems that include it, and owner reports.

Where to buy

Our verdict

Sonos Sub 4

Best for: Sonos home theaters in bigger rooms

Woofers

Dual 5 x 8-inch elliptical, force-canceling

Rated low end

As low as 25 Hz

Connectivity

Wi-Fi 6, 10/100 Ethernet

Size (H x W x D)

15.31 x 15.83 x 6.22 in

Weight

25.99 lb

• Pairs with every current Sonos soundbar
• Stands upright or lies flat under a sofa
• Two-sub setups supported with Arc Ultra and others
• Trueplay and app sliders balance it with the bar

• No RCA, LFE or other wired audio input
• Little audible change from the Sub (Gen 3)
• Not supported by the S1 app, Playbar or Playbase

Watch for: It needs an amplified, non-portable Sonos product to pair with, so Move, Roam and Port owners cannot use it.

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What are the Sonos Sub 4 key specs?

Specs come from Sonos's tech-spec page, checked October 24, 2026. Sonos publishes no amplifier wattage or maximum output figure, and no major lab has measured the Sub 4 on its own.

Sub 4 or Sub Mini: which one fits your room?

This is the real decision for most Sonos owners, and it comes down to room size, which speaker you pair it with, and whether you will ever want two subs.

Sub Mini figures come from Sonos's Sub Mini page, checked October 24, 2026. Both reach the same rated 25 Hz. The difference is how much air they move. The Sub 4's larger ported cabinet plays louder bass with more headroom, so explosions and big cinematic moments hit your chest. The sealed Sub Mini gives tight, clean bass at moderate levels and runs out of steam sooner in a big, open room.

Match the sub to the bar. The Sub Mini is the natural partner for a Ray or Beam in a bedroom, a small lounge or an apartment with shared walls. The Sub 4 is the natural partner for an Arc Ultra or Arc, a pair of Era 300s or a Five, especially in an open-plan space. A Beam in a larger room can take a Sub 4 without being overpowered, and an Arc Ultra in a small room can do well with a Sub Mini, since the bar already has strong bass of its own.

Two practical points settle many cases. The Sub Mini cannot run as a pair, since Sonos's two-sub rules cover only the Sub 4 and Sub (Gen 3). And the commonly reported impression is that the Sub Mini is more sensitive to where you put it, so start it on the same wall as the soundbar, ideally near a corner.

What does the Sub 4 pair with?

Sonos's support page spells out the rules. Sub 4 works with all Sonos home theater speakers except the old Playbar and Playbase. On the soundbar side that means the Arc Ultra, Arc, Beam (Gen 2), Beam (Gen 1) and Ray, and the support page also covers the Beam Ultra. On the speaker side it pairs with the Five, Era 300 and Era 100, and it works with the Amp, including in two-sub setups.

It will not pair with portable or streaming-only products. No Sonos Sub works with Move, Roam, Port, Connect or older ZP models, and Sub 4 specifically does not support Play:1, Play:3, Play:5 (Gen 2), Connect:Amp or the first-generation IKEA SYMFONISK bookshelf and table lamp. Sub 4 also does not work with the S1 Controller app, so an older S1 system needs to move to the current app first.

For music, pairing it with a stereo pair of Era 300s or a Five gives a full-range system without a receiver. Our Sonos Era 300 review and Sonos Five review cover those speakers.

Can you run two subs?

Some Sonos home theater setups accept two subwoofers. The Arc Ultra and Beam Ultra take two Sub 4s, two Sub (Gen 3)s, or one of each. The Arc, Beam (Gen 1 and 2), Ray and Amp can pair a Sub 4 with another Sub 4 or a Sub (Gen 3).

Both subs share the same level and phase settings in the app. Two subs are worth it in a multi-seat room for a simple reason: one sub can only be optimized for one seat, and two properly placed subs give more even bass across the sofa with fewer dead spots. The second sub buys you consistency more than volume.

What changed in the Sub 4 from the Sub (Gen 3)?

The Sub 4 gets a faster processor, more memory, a Wi-Fi 6 radio and up to 50 percent lower idle power use. The finish is now matte, which hides fingerprints far better than the old gloss, and the Sub 4 is lighter than the Gen 3.

In use the two are not dramatically different, and there is no reason for a Gen 3 owner to upgrade. If you can find a Gen 3 discounted or used, it does nearly the same job, and it can still pair with a Sub 4 later in setups that support two subs.

How does the Sub 4 sound?

The closest published measurement is of the Sonos Ultimate Immersive Set with Arc Ultra, which bundles the Arc Ultra, two Era 300s and a Sub 4. That system shows ample low-end extension that captures sub-bass in hip-hop and electronica, kick drums with plenty of rumble and punch, and little compression when pushed to max volume.

The Sub 4 itself only produces a little distortion at maximum level on the bassiest tracks. The app's sub level slider goes up to +15, which is far more than most rooms need, so start near zero and adjust from your seat.

The inward-facing woofer pair cancels cabinet vibration, which is why Sonos promises no buzz or rattle. With a soundbar, Sub 4 also takes over the lowest frequencies so the bar can spend its drivers on mids and highs. That is why dialogue often sounds clearer after you add a sub, not just bassier.

How do you place and set up the Sub 4?

Setup is simple: plug it in, open the Sonos app, select the room, and choose Connect Sub. If you are setting up a new soundbar and Sub 4 together, set up the soundbar first.

The sub connects wirelessly to the primary Sonos product and must be in the same room. Keep at least one side of the central opening unobstructed, and if it stands upright against a wall, do not block the front opening. Sonos supports laying it flat, even under a sofa, but nothing should sit on top of it. If Wi-Fi in that spot is weak, the Ethernet port lets you hardwire it to your router.

Once it is placed, run Trueplay. Trueplay sets the Sub's phase, and you cannot change phase manually while Trueplay tuning is on. Sonos's Sub Mini page lists Trueplay as needing a supported iOS device, so check the requirement for your own setup. Without Trueplay, flip the phase between 0° and 180° and keep whichever gives more bass at your seat.

To choose the spot, try the subwoofer crawl. Put the sub on your seat, play a slow bass sweep, and move around the floor at the height the sub will sit until you find the smoothest bass. Then put the sub there.

What do Sub 4 owners report?

Owners rarely regret the Sub 4. One added it to a pair of Era 300s over the holidays using the extended return window and decided to keep it, saying it makes a huge difference for movies and music. Owners pairing it with an Arc Ultra describe the result as incredible, though one admits the bar alone was strong enough that a Sub Mini might have done.

Apartment owners report no trouble when they keep the level low. One runs two Sub 4s at around -8 most of the time for even bass with few dead spots. And an owner who has both a Sub 4 and a Sub Mini paired with Arc Ultras prefers the Mini, finding it forgiving enough with plenty of kick for their taste.

What buying mistakes should you avoid with the Sub 4?

The most expensive mistake is buying a Sub 4 for a Ray or a Beam in a small room. The Sub Mini costs far less and suits that setup better.

The second is buying any Sonos sub for a non-Sonos system. It has no wired input, so it will not work with a receiver or another brand's soundbar, full stop.

The third is upgrading from a Sub (Gen 3). You pay full price for very little change. If you want more bass, add a second sub instead.

And check your app before you buy. A system still on S1 needs to move to the current Sonos app before a Sub 4 will pair.

Who should buy the Sub 4, and who should skip it?

Buy the Sub 4 if you own an Arc Ultra, Arc or Beam and your living room swallows its bass. It also suits you if you want to add two subs to an Arc Ultra for more even bass across seats, or if you use Era 300s or a Five for music and want full-range sound without a receiver.

Skip it if you run an AV receiver or a non-Sonos soundbar, if you already own a Sub (Gen 3), or if you have a Ray or Era 100 in a small room, where the Sub Mini fits better. Skip it too if you are still on the S1 app or use a Playbar or Playbase.

What are the alternatives to the Sonos Sub 4?

The Sonos Sub Mini is the compact option at 12.01 x 9.06 x 9.06 inches and 14 lb, with two inward-facing 6-inch woofers in a sealed box. Sonos pitches it for products such as the Era 100 and Ray, and the Sub 4 costs roughly double. Start here for small rooms. Read our Sonos Sub Mini review.

The Sonos Sub (Gen 3) sounds close to the Sub 4 in use and weighs a little more. It is worth buying discounted or used, and it can pair with a Sub 4 later.

The Bose Bass Module 700 is the equivalent decision for Bose owners, and just as locked to its own ecosystem. Our Bose Bass Module 700 review covers which Bose bars it works with.

If you are not committed to Sonos, a wired 12-inch sub like the Klipsch R-121SW is rated to 28 Hz and 118 dB and works with any AV receiver. The Sonos Amp is the one Sonos product it can join, through the Amp's RCA subwoofer output. For a cheaper wired option, see our Klipsch R-100SW review.

If you are still choosing a soundbar, our Sonos Beam Gen 2 review and Sonos Ray review cover the two smaller bars that Sub 4 supports. For other bass options, see the best compact subwoofers for small rooms or the Philips X5206 party speaker.

Frequently asked questions

Sources

• Sonos: Sub 4 product page and tech specs
• Sonos Support: Set up your Sonos Sub (compatibility and two-sub rules)
• Sonos: Sub Mini tech specs
• What Hi-Fi?: Sonos officially unveils the Arc Ultra and Sub 4
• Pickr: Sonos Sub 4 reviewed
• RTINGS: Sonos Ultimate Immersive Set with Arc Ultra review
• Sonos: Amp tech specs (subwoofer output)
• Bose: Bass Module 700 product page
• Klipsch: Reference R-121SW spec sheet (PDF)
• Sound & Vision: Subwoofer setup in 3 steps