Open Terminal and enter “sudo defaults read bluetoothaudiod” and type in your password when prompted. You should then see the current settings:
"AAC Bitrate" = 128;
"AAC CBR" = 0;
"Apple Bitpool Max" = 64;
"Apple Bitpool Min" = 2;
"Apple Initial Bitpool" = 40;
"Disable HFP" = 0;
"Enable AAC codec" = 1;
"Enable AptX codec" = 0;
If you get an error “Domain bluetoothaudiod does not exist”, that means none of these settings have been set before, update the setting as shown below and you’ll be able to read the setting as outlined above.
To update these settings in the Terminal:
to enable AptX:
sudo defaults write bluetoothaudiod "Enable AptX codec" -bool true
to enable AAC:
sudo defaults write bluetoothaudiod "Enable AAC codec" -bool true
To disable either one, just change “-bool true” to “-bool false” at the end of the command.