Hello, i have experienced a strange problem. I am mainly using Sony WF-1000XM3 earbuds. During this summer i have experienced a problem where suddenly the call quality over bluetooth dropped dramatically, and permanently. I believe my phone is now using the narrow band CVSD protocol (really early hand-free bluetooth protocol) or similar, where it used to use mSBC or another more modern protocol. I started receiving complaints about my friends not hearing me properly, and i noticed that their voice sounded really muffled too.
For a test i paired WF-1000XM4:s with my phone, and voice calls and discord sounded crisp. So the issue only affected the protocol used with my XM3’s. I resetted the earbuds, and did a factory wipe on them. They have not received any firmware updates for a long time (i think 2 years now) so it is not in my mind plausible that Sony rolled out anything that caused this. I deleted the device pair on my phone, and rebooted. Re-paired the now completely resetted earbuds and voice calls and voice chat over discord still use the really bad sounding protocol. I connected the XM3’s to my PC and to my surprise the voice calls and discord chat sounded crisp on my PC!
So i have isolated the issue to be only with WF-1000XM3’s and the Fairphone 5.
Unfortunately i see no settings even in developer settings that i can change in relation to the protocols used over bluetooth in voice mode. I see only options related to bluetooth audio protocols (they are all in their default settings).
Have any of you experienced this call drop quality with XM3’s or some other earbuds?
The only thing i have not done is a factory reset on my FP5. It is hard to isolate when exactly this problem started to be encountered by me, but it was sometime this summer so i suspect if this is a software bug it was caused by one of the last two or three updated that i have installed during the summer.