Macbook Pro 2015. Everything has worked fine. Updated from 11.7.4 to 11.7.8 (yes I know I'm running older OS because it is al older computer) and the crackling problem now happens to me too. First it was right speaker. Panning to left allowed me to work around it for web calls yesterday. Now it is both speakers. Crackling is there even at very low volumes, so I don't think this is a blown speaker issue. If it is, it is very strange that both speaker **** out 1 day apart from each other. Reset SMC, PRAM. No difference. Killed coreaudiod, no difference. Restarted, no difference. Ran hardware diagnostics, all clear. Cranked up the volume and reboot. Crackle is present on startup chime, so I am guessing this is an audio firmware issue rather than a coreaudio driver level issue. So now I am trying to research exactly what firmware updates were applied between 11.7.4 and 11.7.8 and whether it is possible to downgrade the audio firmware if an update was applied. Pretty sure clean installing to Mojave/Catalina or earlier Big Sur will not downgrade the firmware but I may try that too eventually. What a waste of time this expensive hardware is. Super annoying as the laptop is useless for anything that requires audio now because of applying an update. THIS is why I tend to avoid apple OS updates as long as possible, security be damned. Too much waste of time to learn UI changes and have things broken preventing me from getting work done. I know Apple is not too concerned with supporting older hardware, but I'm unlikely to continue buying their hardware with infuriating issues like this that apparently have been going on for a long time without resolution across a range of laptop models.