When you are listening to something or watching a video, the A2DP profile is used by default, but when on a call, it automatically switches to HSP HFP. This also means that the audio switches from stereo to mono, disabling any spatial effects. That why the audio quality degrades almost instantly. Although Bluetooth connectivity and audio transmission have improved significantly over the years, this remains a major drawback. And while manufacturers have been trying to find ways around it, there...
