Quality dropping with Bluetooth earbuds

[lebruit]

Hi! I have a specific problem with Poweramp, and I'm sure there is a solution somewhere, but I haven't figured it out yet.

I have recently bought a new pair of Bluetooth earbuds that come with a charging case. The audio quality is very good when I use both earbuds; no complains here.

I'm a cyclist, so I often use only one earbud to hear my surrondings. I went on a ride with my earbud (the right one), with my playlist on Poweramp, and noticed the sound quality was muddy. I could hear audio artifacts on some tracks. When I came back home, right earbud still in my ear, I opened up the charging case (with the left earbud I left inside), and immediately, the sound in the right earbud became clearer, as if I was wearing both earbuds. I closed the charging case, and the right earbud became muddy again. I have tested this situation with one particular on Youtube, and the audio quality wasn't changing when I played it from there. This leads me to think there is something in Poweramp that makes the audio quality shifts when pairing with one earbud vs two earbuds.

What could be the source of that, and how to fix it?

[Fitzian]

Sounds like the earbuds are doing some sort of stereo->mono downmix when it senses one of the earbuds are not in use.

[lebruit]

I have encountered this problem only when using Poweramp, and not with other apps. Any setting I might tweak so this downmix doesn't happen?