Hey Seven.of.nine,
as far as I know there is only one dirty workaround:
Check for the current connected bluetooth device ID:
pacmd list-sinks
and set the maximum volume to 200%
pacmd set-sink-volume <dev. ID> 131072
where 65536 means 100% and 131072 corresponds to 200%
But there are at least two drawbacks of this workaround:
- The device ID changes whenever you reconnect the device (this is why it should be rechecked every time you start up the bluetooth connection)
- The sound quality tends to be bad the more you turn it up. It starts clipping somehow. This gives me the impression that wie tweak with the wrong parameter.
Here you find some other contributions to this topic:
https://forum.sailfishos.org/t/bluetooth-headset-audio-boost/1565
Would be great if anybody can help with that.