Direct answer
For the Sonos Sub (Gen 3), trigger, range, interference, competing hosts, battery and firmware should be recorded. First, test charged devices nearby with other hosts' Bluetooth off.
What this covers
- Sonos Sub (Gen 3) (Sub Gen 3)
- Sonos product; Wi-Fi/Ethernet, Bluetooth, voice, home-theater and line-in capabilities vary.
- The specific fault this record addresses: keeps disconnecting
What it does not cover
- ×The same symptom on a different Sonos product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
The body is between the source and the accessory
What separates it Dropouts when the phone is in a back pocket, or when turning a particular way.
How to confirm Bluetooth is heavily absorbed by water, and a body is mostly water. Moving the phone to a front pocket or the other side commonly resolves it entirely.
- 2
2.4 GHz interference
What separates it Dropouts in specific locations — near a router, a microwave in use, or a crowded office.
How to confirm Bluetooth shares the band with Wi-Fi and microwave ovens. Interference is location-specific and moving a few metres often confirms it.
- 3
The battery is low
What separates it Dropouts increasing as the charge falls.
How to confirm Low battery reduces transmit power and causes instability well before the device shuts down.
- 4
The accessory is trying to switch between two paired devices
What separates it Brief dropouts with a phone and a laptop both nearby and both paired.
How to confirm Multipoint devices switch automatically and can oscillate. Disconnect one of the two while testing.
- 5
Firmware needs updating
What separates it Dropouts that began after an update, or a known issue in a specific release.
How to confirm See app-update — connection stability is one of the most common subjects of audio firmware fixes.
- 6
A Wi-Fi speaker is dropping off the network rather than off Bluetooth
What separates it A mains speaker or soundbar disappearing from the app.
How to confirm These are network devices, so this is a Wi-Fi problem: check signal strength at the speaker's position and whether its address has changed.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Where the source device is carried when dropouts happen — a back pocket puts a body directly in the path.
- Whether dropouts are location-specific, which points at interference.
- The battery level when it happens.
- Whether two devices are paired simultaneously.
Move the phone to a front pocket or hold it in your hand
ReversibleBluetooth is strongly absorbed by the body, and a phone in a back pocket puts a body directly in the radio path.
Test in a different location
ReversibleInterference from Wi-Fi equipment and microwave ovens is location-specific and moving a few metres usually confirms it.
Charge the accessory fully and retest
ReversibleLow battery reduces transmit power and destabilises the link well before the device stops working.
Disconnect the second paired device while testing
ReversibleMultipoint devices can oscillate between two sources, producing brief repeated dropouts.
Install any pending firmware update
ReversibleConnection stability is among the most commonly fixed issues in audio firmware.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- Sub Gen 3. Sonos product; Wi-Fi/Ethernet, Bluetooth, voice, home-theater and line-in capabilities vary.
- Type — wireless subwoofer (mains-powered)
- A mains-powered wireless subwoofer that bonds to a Sonos soundbar or speaker pair over WiFi to add deep bass. It has no battery and no standalone function — it only works bonded to another Sonos product in the app.
- Bonding
- 'No bass / Sub not working' is usually the bonding: confirm the Sub is added to the same room as the soundbar in the Sonos app and is on WiFi. It must be assigned to a soundbar/speaker to do anything.
- Placement & level
- Sub bass is adjustable in the app; a Sub in a corner sounds boomier. If bass seems wrong, run/adjust the level and Trueplay tuning rather than assuming a fault.
- Symptom boundary
- This record covers Sonos Sub (Gen 3) when it keeps disconnecting. A different symptom on the same hardware, or this symptom on a different Sonos product line, has its own record with its own causes and its own cited source.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. Sonos publishes this as "Products missing from the Sonos app". a Sonos product that keeps dropping off shows up as missing from the app; this is that path. Probed 2026-08-21: title-verified. What that article does not carry is the model boundary — it is written for a product line, and Sub Gen 3 is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
My Sonos Sub isn't producing any bass.+
The Sub only works when bonded to a Sonos soundbar or speaker pair, so first confirm in the Sonos app that it is added to the same room and shows connected. It also needs power and WiFi. If it is bonded and still silent, adjust the Sub level in the app (it may be turned down), check placement (corners boom, open floor is flatter), and re-run Trueplay. A Sub that will not bond at all is usually a WiFi/network issue.
My earbuds cut out when I put my phone in my back pocket.+
That is expected physics rather than a fault. Bluetooth is strongly absorbed by water, your body is mostly water, and a phone in a back pocket puts your body directly between the transmitter and your ears. Moving the phone to a front pocket or carrying it in your hand resolves it almost every time.
Does this answer apply to every Sonos model?+
No. It is scoped to Sub Gen 3. Sonos product; Wi-Fi/Ethernet, Bluetooth, voice, home-theater and line-in capabilities vary.
What should I record before troubleshooting disconnecting or drops?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing disconnecting, drops. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Stop for swelling, heat, liquid or damaged ports.
Answer for the exact device and software version shown above.