For one ear silent on the QC Ultra Headphones, Bose's article lists four checks. Try a different app: if only one app does it, it is the app or its settings. Try different types of media, since podcasts, local files, streaming services and videos vary in quality and one may be mono or unbalanced. Reboot the headphones by holding Power/Bluetooth while connecting the USB cable to the left earcup until the light blinks twice; this does not erase settings. Check the headphone cable if you use it: if the plug or any part is damaged, replace the cable.
The no-audio article adds trying another Bluetooth source and clearing the memory of paired devices. For earbuds Bose has separate articles for one earbud that will not connect or power on: place both in the case, check the stability bands, look for a magnetic snap and a lit LED, reboot the phone, reset the earbuds from the case, and then clear the pairing list. If one earbud stays dead after a factory reset, it needs replacing through Bose, which is what its repair button starts.
Differential
Likely causes of “Bose QuietComfort headphones and earbuds plays from only one side or channel”, and how to tell them apart
- 1
A mono or unbalanced source
What separates it One ear plays in one app because the source is mono or unbalanced
How to confirm Try a different app and different media, to see whether the fault stays
- 2
A damaged cable
What separates it One side fails only on the cable because the cable is damaged
How to confirm Replace the damaged cable with a new one
- 3
An earbud not seated in the case
What separates it One earbud is dead because it is not seated in the case
How to confirm Seat it so it snaps and the LED lights
- 4
A stale pairing
What separates it One earbud will not connect because of a stale pairing
How to confirm Clear the pairing list, and pair the headphones again from the start
- 5
A hardware fault
What separates it One side stays dead everywhere, which points to a hardware fault
How to confirm Start a repair or a replacement with Bose, since the fault is in the hardware
Before you touch a setting
Record this first — changing settings destroys the evidence
- The product and which side fails
- Whether it follows the app, the source or the cable
- Whether the earbud powers on and the case LED lights
- Whether a factory reset changed anything
Try in this order
0 of 6 completedChange app
ReversibleChange the app, and try another app, to see whether one side still fails, and then test again to see whether it helped.
Change media
ReversibleChange the media, and try different types of media, such as music and video, and then test again to see whether it helped.
Check the cable
ReversibleCheck the cable, and replace it if it is damaged, and then test again to see whether it helped.
Reseat the earbuds
ReversibleReseat the earbuds, by seating them in the case until they snap and the light comes on.
Clear and re-pair
ReversibleClear and re pair, by clearing the pairing list and pairing the headphones again, and then test again to see whether it helped.
Start a repair
ReversibleStart a repair, if one side stays dead, and begin a repair or a replacement with Bose.
Model-specific
What is true of this model and not of its siblings
- Earbuds versus headphones
- Headphones share one Bluetooth link and a cable option; each earbud has its own connection to the case, so one can drop while the other plays.
- Fit kit
- The QC Ultra Earbuds ship with three pairs of eartips and three stability bands, and Bose says poorly aligned bands are the commonest charging problem.
- Other models this page answers
- These steps also fit the QuietComfort Headphones.
Stop boundary
When this stops being a self-service repair
- !If one side is silent on every source after a reboot and reset, start a repair or replacement with Bose
- !If one earbud will not power on, replace it through Bose
- !If it follows one app, contact that app
Evidence ledger
Sources behind this answer
Different app, different media, reboot and the cable.
Case reboot, clearing the pairing list and factory reset.
Stability bands and case seating.
Clearing memory.
The company and its products.
Exact questions
Common questions
Why is one ear silent?+
An app, media, cable or seating problem; Bose lists these checks.
Does the reboot erase settings?+
No, the reboot does not erase your settings, so it is safe to try.
Does the cable cause it?+
A damaged plug or cable can.
Why is one earbud dead?+
It may not be seated in the case or need a reset.
How do I reset earbuds?+
Reboot in the case, then clear the pairing list or factory reset from the case button.
How do I check the case?+
Look for a lit LED and a magnetic snap.
Can one earbud be replaced?+
Bose's repair button starts a replacement.
Should I test on another device?+
Yes, test on another device, by trying another Bluetooth source.
Could it be my ears?+
Test with another pair of headphones, to rule out a problem with your ears or the source.