I have written about Audio Hijack here before, their app that allows you to record audio from other applications (and that's just the start of all the powerful things it can do). So what do you do? Rogue Amoeba makes excellent Mac apps that, for lack of better explanation, hack into the audio system of your Mac. And in some cases, it creates issues with echo, delay, or a nasty feedback loop. But it isn't going to produce a pure representation of the audio I am trying to send. Sure, you can play it right on your computer and let the audio from your speakers go straight back into the microphone input of your computer. Have you been teaching a class in Google Meet or Zoom and wanted to play a song from iTunes for your digital classroom? Or perhaps a YouTube video or any other application with audio?