OK, so I've found out that the crackling only starts when I change the audio output for the first time after starting Ubuntu up. After that, it only stops if I restart the pulseaudio service, or by restarting the PC. So, the issue clearly has something to do with the change in output audio device.
OK, so I've found out that the crackling only starts when I change the audio output for the first time after starting Ubuntu up. After that, it only stops if I restart the pulseaudio service, or by restarting the PC. So, the issue clearly has something to do with the change in output audio device.