Bluetooth audio devices that have a micorphone often default to the HSP quality level when connected to a Linux system, which is incredibly annoying.
To change the audio codec to use when it auto-connects, try this:
Open the default file for PulseAudio, found at /etc/pulse/default.pa.
# Change this line
load-module module-bluetooth-policy
# To this
load-module module-bluetooth-policy auto_switch=2
This neat trick was found originally here.