Comment 4 for bug 1828393

This is not a duplicate bug, bug 508522 covers automatic switching of profiles since a2dp and hsp/hfp are mutually exclusive, there can not be two profiles active at the same time.

The true bug here is the bad voice quality, which is caused by a lack of codec negotiation. This is why bluetooth headsets will sound better connected to a random (> 4.4) android phone, which will negotiate mSBC, also known as "wide band speech", supported since HFP 1.6. This can be mistaken for "a2dp and microphone active at the same time", even though it is still a monaural configuration not related to a2dp, because it sounds so much better.

The HSP/HFP mode is using the CVSD codec which sounds like a bad gsm call, there have been attempts to merge proper codec negotiaton, but the work has stalled for some reason - see the related thread at https://www.spinics.net/lists/pulse-audio/msg29370.html and the stale patchset at https://patchwork.freedesktop.org/series/30716/