Bose's no-audio article for the QC Ultra Headphones starts with a trap: Bluetooth is disabled while charging, so unplug them or use the backup audio cable, and note the headphones must be powered on even when wired, and Bluetooth is off while the cable is connected. Plug the smaller cable end into the jack at the bottom of the left earcup and the other into a 3.5 mm jack; a depleted battery can use the USB cable and the audio cable at once. Reboot the connected device. On Windows connect to the entry with the headphones or speaker icon, not the LE listing.
Reboot the headphones by holding Power/Bluetooth while connecting the USB cable until the light blinks twice. Try a different app: if it fails in only one app it is the app. Try another Bluetooth source to see whether the paired device is at fault, and clear the headphones' memory of paired devices and reconnect. The low audio article for the same product adds turning the volume up on the source and the headphones. For earbuds, seat them in the case, reboot the phone and reset the earbuds. If the audio cable is damaged, replace it.
Differential
Likely causes of “Bose QuietComfort headphones and earbuds connects but has no sound”, and how to tell them apart
- 1
The headphones are charging
What separates it There is no sound over Bluetooth because the headphones are charging
How to confirm Unplug the headphones from the charger, or use the backup audio cable
- 2
The wrong Windows entry
What separates it The headphones are connected but silent because of the wrong Windows entry
How to confirm Choose the headphones icon, not the LE entry
- 3
A source problem
What separates it The headphones are silent with one device only because of a source problem
How to confirm Try another Bluetooth source, to see whether the fault is in the first device
- 4
One app is muted
What separates it The headphones are silent in one app because that app is muted
How to confirm Try a different app, to see whether the silence is only in one of them
- 5
A stale device memory
What separates it There is random silence because the device memory is stale
How to confirm Clear the memory on the headphones, and pair them again
Before you touch a setting
Record this first — changing settings destroys the evidence
- The source device and whether audio plays elsewhere
- Whether a cable is connected and whether the headphones are on
- The app that fails to play any sound
Try in this order
0 of 6 completedUnplug the charger
ReversibleUnplug the charger, since Bluetooth is off while the headphones are charging, and then test again to see whether it helped.
Try the audio cable
ReversibleTry the audio cable, by using the backup cable with the headphones switched on, and then test again to see whether it helped.
Reboot the device
ReversibleReboot the device, by restarting the phone or the computer, and then test again to see whether it helped.
Pick the right Windows entry
ReversiblePick the right Windows entry, which is the headphones icon and not the one marked LE.
Change app and source
ReversibleChange the app and the source, by testing another app and another device, and then test again to see whether it helped.
Clear memory
ReversibleClear the memory, by clearing the pairing list, and then reconnect the headphones, and then test again to see whether it helped.
Model-specific
What is true of this model and not of its siblings
- Backup cable
- Bose says the audio cable disables Bluetooth and the headphones must be powered on to work with it.
- Earbuds
- The earbuds have no audio cable; use the case reboot and reset.
Stop boundary
When this stops being a self-service repair
- !If a rebooted headset is silent on several sources and with the cable, start a repair or replacement with Bose
- !If only one app is silent, contact that app
- !If the audio cable is damaged, replace it with a new one
Evidence ledger
Sources behind this answer
Charging, backup cable, Windows listing, reboot, other apps and clearing memory.
Different apps and media and the cable condition.
Earbud reboot steps.
Clearing memory.
The company and its products.
Exact questions
Common questions
Why is there no sound?+
Bluetooth is disabled while charging, or the source or app is at fault.
Can I use the cable?+
Yes, but the headphones must be powered on and Bluetooth is off.
Where is the audio jack?+
At the bottom of the left earcup.
Why is Windows silent?+
You may have chosen the LE listing.
Does a reboot erase settings?+
No, a reboot does not erase your settings, so it is safe to try.
What if only one app is silent?+
It is likely the app or its settings.
How do I check the source?+
Check the source by pairing a different Bluetooth device, and testing the sound.
Is the cable at fault?+
If the plug is damaged, replace it.
Does low battery matter?+
A depleted battery can use the USB and audio cable together.
Can Siri change Bose modes?+
Yes, for example Change my Bose Mode to Quiet.