The Sonos App has no crackle? You are playing video sources through the Sonos App? All other audio-only tracks are playing okay? I’m not sure I understand the issue you are reporting here, but it sounds like it’s perhaps related to the video aspect of your tracks. I didn’t think the Sonos App built-in Apple Music service could play video files, but I don’t use that service.. these are the normal file-types that the Sonos App can play:

https://support.sonos.com/s/article/79

This link relates to connected A/V services, but these have no bearing on the Sonos App/built-in Apple Music Service:

https://support.sonos.com/s/article/4945

https://support.sonos.com/s/article/5005

I didn’t understand your question, but maybe the above links will assist you, perhaps?

Ignore the Apple Music part of the equation- that was just info to stay that the speaker itself is fine. There isn't electrical interference from the power supply or a broken fan.

The problem definitely seems to be signal loss/bad/missing information somewhere between Arc and the video source. The tiny intermittent crackles and blips of silence are not accompanied by loud sounds like popping or screeching. It's like the Arc didn't understand something and just decided not to translate for that fraction of a second.

My question is which element needs replacing/updating? Everything meets specs.

Guess I just start Amazon Prime-ing substitute components until I can eliminate the problem’s source. I better hurry so I'm not stuck with a nice music system I don't use.