I’ve noticed audio quality on Mac’s is a bit of a hit & miss affair; until I read this article about terminal hints to fix stupid default Mac settings.
Applied the terminal hints, and happiness! In case it gets removed,
defaults write com.apple.BluetoothAudioAgent "Apple Bitpool Max (editable)" 80
defaults write com.apple.BluetoothAudioAgent "Apple Bitpool Min (editable)" 48
defaults write com.apple.BluetoothAudioAgent "Apple Initial Bitpool (editable)" 40
defaults write com.apple.BluetoothAudioAgent "Negotiated Bitpool" 58
defaults write com.apple.BluetoothAudioAgent "Negotiated Bitpool Max" 58
defaults write com.apple.BluetoothAudioAgent "Negotiated Bitpool Min" 48