HDB Bluetooth audio quality bug

Support
1

Issue description:

Hello, I have previous contacted you by email involing a bug with using my HDB 630s in Bluetooth. I already typed up my issue so I’m going to copy paste it for the sake of clarity. Ignore if you’re already caught up.

"Anyway, the issue I’m having is that when I connect my Sennheiser HDB 630s via Bluetooth, for about 10 to 20 second the audio will sound like garbage and seems to be in mono before seemingly fixing itself. aptX adaptive is the codex being used and this audio bug doesn’t seem to happen in other players / headphones (admittedly wired).

The really strange part is that if I leave the app open (like displaying on screen) it won’t fix itself, I have to go to home or use another app and the audio will fix. And if I open the app back (while playing audio) the quality will degrade again untill I minimise the app again and after the 10 to 20 second it fixed once again. My files are (only) 44 khz flacs, no 96 khz files and I don’t use any eq in Symfonium if that matters. Using the BTD 700 instead of Bluetooth fixes this issue but I would like to use Bluetooth. Any help would be appreciated."

I enabled debug mode and performed the bug in the middle of a track before uploading the logs as HDB 630 Bluetooth bug.

Logs:

Upload description: HDB Bluetooth bug

Additional information:

 
Occurs on both streamed and downloaded music
 

Reproduction steps:

 
Play song, audio is crusty, open a different app with song playing in background, audio fixes itself untill I open Symfonium again and in a few seconds it goes back to being crusty. Sometimes if I open the app and quickly (less then a second) pick another song it won’t go crusty.
 

Media provider:

Subsonic

Screenshots:

     

2

I don’t see anything special in the logs. Just that the device seems ultra slow. try to run settings/advanced/ cleanup internal state wait a couple of minutes then compact database.

The only thing is that there’s auto cache rules on large playlists running at some point, so it could impact the CPU but should not be impacted by the app being visible or not.

3

I have figured out the issue. After traveling with the HDBs I noticed that the bug fixed itself only to return once I arrived home. Turns out connecting to 2.4ghz wifi causes this bug and switching to 5ghz wifi (or mobile data) fixed it.

I believe the issue is caused by my phone’s 2.4ghz band getting maxed out when connected to 2.4ghz wifi and the Bluetooth headphones (which operate at a similar frequency) at the same time, compromising the quality of the Bluetooth signal when it’s trying to connect to the media provider, that’s my theory anyway. Also I’ll try the cleanup and compact database but I believe the device just is that slow.