Sonos Sub Gen 4 Review 2025: What Happens When Bass Finally Gets Done Right
Most people do not realise how much they are missing until they hear it. That physical sensation of a bass note moving through a room. The way an explosion in a film does not just sound loud but actually feels like something happened. The low frequency detail in a well recorded piece of music that you never knew was there because your existing speakers were quietly giving up on it.
The Sonos Sub Gen 4 is built around that realisation. It is not an addition to your audio setup. It is the part that makes everything else make sense.
If you already own a Sonos soundbar or a pair of Sonos speakers and you have been wondering whether a dedicated subwoofer is really worth the investment, this review is going to answer that question clearly and honestly.
What Is the Sonos Sub Gen 4
The Sonos Sub Gen 4 is the fourth generation of Sonos’ flagship wireless subwoofer. It pairs wirelessly with any compatible Sonos speaker or soundbar and adds a dedicated low frequency channel to your audio system. No subwoofer cable running across the floor. No separate amplifier to find space for. It connects to your home network over Wi Fi and communicates directly with your Sonos system.
The Gen 4 builds on the already excellent Gen 3 with a more powerful processor, expanded memory, and improved wireless performance. The core acoustic design, which has been refined over multiple generations, remains largely unchanged because it was already very good. What has changed is the intelligence running underneath it.
Design and Build
The Sonos Sub Gen 4 has one of the most distinctive designs in home audio. It is a flat rectangular cabinet with a slot cut through the centre, and two force cancelling woofers mounted face to face on opposite sides of that slot firing inward toward each other. This is not a design choice made for aesthetics. It is an acoustic engineering decision that has real consequences for how the subwoofer sounds and behaves.
The cabinet comes in matte black or matte white, matching the rest of the Sonos range. It can be placed upright on the floor, laid flat under a sofa or TV unit, or positioned in a corner. It is 158mm deep, 388mm wide, and 402mm tall in its upright orientation, which makes it genuinely compact for a subwoofer that performs at this level.
The finish is smooth and clean. There are no visible driver cones, no ports, no grille that collects dust. It looks like a piece of furniture rather than a piece of audio equipment, which matters more than it probably should but there it is.
The Force Cancelling Woofer Design: Why It Matters
This is worth understanding because it explains a lot about why the Sonos Sub sounds the way it does.
Most subwoofers work by moving a large driver in and out at low frequencies. The problem with this approach is that the physical motion of the driver creates vibration in the cabinet itself. That cabinet vibration couples into the floor, the furniture, and the walls around it, adding a layer of unwanted resonance to the sound. It is part of why cheap subwoofers sound muddy and indistinct rather than tight and controlled.
The Sonos Sub solves this by mounting two identical woofers facing each other inside a sealed enclosure. As one driver pushes forward, the other pushes backward. The equal and opposite forces cancel each other out at the cabinet level, which means the cabinet itself does not vibrate. The energy goes entirely into moving the air in the room rather than shaking the floor beneath the subwoofer.
The result is bass that is clean, accurate, and free from the low level rumble and cabinet noise that plagues most subwoofers in this price range and well above it. You hear the bass you are supposed to hear and nothing you are not.
How It Sounds
If you have been living with a Sonos soundbar or a pair of Sonos speakers without a subwoofer, the first time you play music or a film with the Sub Gen 4 added to the system is a genuinely surprising experience.
The low end appears. Not in an aggressive or obviously boosted way. It is more like something that was previously absent simply arrives and settles into its rightful place. The system sounds complete in a way it did not before.
For music, the Sub Gen 4 adds genuine depth to recordings that have it. The bass guitar on a well recorded soul or funk track has weight and articulation. Orchestral music gains the low frequency foundation that string basses and bass drums provide in a real concert hall. Electronic music with sub bass content suddenly has physical presence rather than just audible presence. You feel the room change when a low note arrives.
For film and television, the difference is arguably even more dramatic. Explosions, impacts, thunder, deep engine sounds, all of these have a physicality that even very good soundbars cannot fully reproduce on their own. Dialogue stays clea4part of the frequency spectrum that was missing and then steps back. That restraint is what separates a well designed subwoofer from a showroom demo piece that impresses for five minutes and exhausts you for the rest of the evening.
Setup and Integration
Setting up the Sonos Sub Gen 4 is straightforward. Open the Sonos app, navigate to settings, add a product, and the Sub will appear on your network ready to be added to your existing room. The pairing process takes under two minutes and requires no technical knowledge.
Once paired, the Sub communicates wirelessly with your soundbar or speakers over a dedicated connection that is separate from your main Wi Fi network. This means the audio synchronisation between the Sub and the rest of your system is tight and consistent. There is no perceptible lag between the bass frequencies coming from the Sub and the mid and high frequencies coming from your soundbar or speakers.
Trueplay calibration applies to the Sub as well as the rest of your system. After running Trueplay, the app optimises the crossover point and level balance between the Sub and your other speakers for your specific room. If you move the Sub to a different position, running Trueplay again recalibrates everything automatically.
The Sonos app also gives you manual control over the Sub’s level independently of your main volume, which lets you set the bass balance to your personal preference. Most people will find the Trueplay calibrated default close to ideal, but the flexibility to adjust is useful.
What Sonos Products Does It Work With
The Sonos Sub Gen 4 is compatible with the Sonos Arc, Arc Ultra, Beam Gen 2, Ray, Era 300, Era 100, and Five. It does not pair directly with third party speakers or soundbars outside the Sonos ecosystem.
The most popular and musically rewarding combinations are the Sub with the Arc or Arc Ultra for a home theatre setup, and the Sub with a stereo pair of Sonos Five speakers for a dedicated music listening system. Both combinations deliver performance that is difficult to match at anywhere near the combined price of the components.
Sonos Sub Gen 4 vs Gen 3
The Gen 4 carries the same acoustic architecture as the Gen 3. The two force cancelling woofers, the sealed enclosure, the overall cabinet dimensions, these are all unchanged. What the Gen 4 adds is a more capable processor with more memory, which improves Trueplay performance and future proofs the product for software features that Sonos may introduce over time.
If you already own a Gen 3 Sub that is performing well, the upgrade is not essential from a pure sound quality perspective. If you are buying new, the Gen 4 is the version to get because the improved processor means it will remain fully supported and capable of running new Sonos features for longer.
Who Should Buy the Sonos Sub Gen 4
The Sonos Sub Gen 4 is the right choice for anyone who owns a compatible Sonos soundbar or speaker system and wants to complete it properly.
If you watch films regularly and want the experience of feeling what is happening on screen rather than just hearing it, the Sub is the single most impactful upgrade you can make to a Sonos home theatre setup.
If you listen to music that has meaningful low frequency content, which covers most genres from jazz and classical to rock, hip hop, and electronic, the Sub adds a dimension to that listening experience that you will notice immediately and miss if it is ever not there.
If you have already invested in a quality Sonos soundbar and are looking for the next step, the Sub Gen 4 is that step. It is not a marginal improvement. It is a fundamental change in what your system is capable of.
Is the Sonos Sub Gen 4 Worth the Price
The Sonos Sub Gen 4 is expensive. There is no point pretending otherwise. But the comparison that matters is not the Sub against a cheaper subwoofer. It is the Sub against what you would need to spend to replicate its performance and convenience with traditional wired equipment.
A wired subwoofer of comparable acoustic quality, combined with the amplification and integration work required to make it function seamlessly with a modern wireless soundbar system, would cost more and deliver a worse user experience. The Sonos Sub Gen 4 is expensive because what it does is genuinely difficult to do well, and Sonos has done it well for multiple generations now.
For a system you are going to use every day for the next several years, the investment makes clear sense.
Quick Specs
Woofers: Two force cancelling drivers mounted face to face Enclosure: Sealed cabinet Wireless: Wi Fi 802.11 b/g/n at 2.4 GHz and 5 GHz Processor: Updated Gen 4 processor with expanded memory Room Calibration: Trueplay via iOS device Dimensions: 158 x 388 x 402mm upright Weight: 16.1 kg Colours: Matte black and matte white Compatible with: Sonos Arc, Arc Ultra, Beam Gen 2, Ray, Era 300, Era 100, Five App: Sonos S2 on iOS and Android
Final Word
The Sonos Sub Gen 4 is what a subwoofer should be. It does not announce itself. It does not dominate the room or shake the walls to prove a point. It simply fills in the part of the sound that was missing and makes everything else around it sound better for its presence.
If your Sonos system has been feeling like it is almost there but not quite, the Sub Gen 4 is the answer to that feeling.
Frequently Asked Questions About the Sonos Sub Gen 4
Q1. Does the Sonos Sub Gen 4 need a wired connection to work?
No. The Sonos Sub Gen 4 connects wirelessly to your Sonos system over Wi Fi. It does require a power cable to be plugged into a wall socket but there is no audio cable or subwoofer cable needed. The wireless connection between the Sub and your soundbar or speakers is handled automatically once the pairing is done through the Sonos app.
Q2. Can I use the Sonos Sub Gen 4 with any soundbar or speaker?
The Sonos Sub Gen 4 works exclusively within the Sonos ecosystem. It is compatible with the Sonos Arc, Arc Ultra, Beam Gen 2, Ray, Era 300, Era 100, and Five. It does not pair with third party soundbars, televisions, or speakers outside the Sonos range. If you are considering the Sub, make sure your existing Sonos speaker or soundbar is on the compatible products list.
Q3. Can I use two Sonos Subs together in the same room?
Yes. Sonos supports pairing two Sonos Sub units in the same room for even greater bass output and improved low frequency coverage across larger spaces. This is particularly useful in large living rooms or home cinema rooms where a single Sub may not provide even bass distribution across the full listening area. Both Subs are managed through the Sonos app and calibrated together via Trueplay.
Q4. Where is the best place to position the Sonos Sub Gen 4?
The Sonos Sub Gen 4 is flexible about placement. It can stand upright on the floor, lie flat, or be placed in a corner. Common positions include next to the TV unit, under a sofa, or in a corner of the room. Because it uses force cancelling woofers rather than a ported design, it is less sensitive to placement position than many conventional subwoofers. Running Trueplay after placing the Sub in your chosen position will optimise the sound for wherever it ends up.
Q5. Does the Sonos Sub Gen 4 work with the Sonos Arc?
Yes and it is one of the most recommended combinations in the Sonos lineup. The Arc paired with the Sub Gen 4 and two rear surrounds such as Era 100 speakers creates a complete 5.1 surround sound system that delivers exceptional performance for both film and music listening. The Sub adds the deep low frequency extension that even the excellent Arc cannot fully provide on its own.
Q6. Is the Sonos Sub Gen 4 an upgrade over Gen 3?
Acoustically the two generations are very similar. The Gen 4 brings a faster processor and more memory which improves Trueplay calibration and ensures the product receives full software support for longer. If you are buying new, the Gen 4 is the right choice. If you own a Gen 3 that is working well, the sonic improvement from upgrading is modest and the decision comes down to whether you want the latest hardware for future software features.
Q7. Can I control the bass level of the Sonos Sub separately?
Yes. The Sonos app lets you adjust the Sub’s output level independently of your main system volume. This means you can turn the bass up or down to match your personal preference and room conditions without affecting the overall volume of your soundbar or speakers. Trueplay sets a calibrated starting point and the manual adjustment lets you fine tune from there.
Q8. Does the Sonos Sub Gen 4 support Trueplay room calibration?
Yes. Trueplay calibrates your entire Sonos system including the Sub as part of a single process. It sets the crossover frequency and level balance between the Sub and your other speakers based on the acoustic characteristics of your room. Trueplay requires an iPhone or iPad to run the calibration process. Android users can still use the Sub fully but the automatic room calibration feature is not available on Android devices.
Q9. How loud can the Sonos Sub Gen 4 get?
The Sonos Sub Gen 4 is capable of filling large rooms with deep, powerful bass at high volume levels without distortion. It is designed for home use rather than professional venue or outdoor use, but within a domestic environment it has more than enough output for any realistic listening scenario. The force cancelling woofer design means it maintains accuracy and control at high levels rather than becoming boomy or distorted as cheaper subwoofers tend to do when pushed hard.