Same issue here. Only bought the tv this past summer. Tried different sound bars and different connections (optical, analog, and even headphones) and the problem persists. I've tried different sound modes in the options menu and nothing solves the problem. For my tv it's most prominent in Disney+ but now it's doing it on all apps. Please fix this TCL or this will be the last tv of yours I ever purchase.
Recently, about last week 1/8/2020 my TCL Roku TV has been distorted sounds. It started on the YouTube App and found a post on here about that and to fix it you pause the stream, hit *, unpause, hit *, and shortly the audio returns to normal. Now it is doing this on all apps and the fix I had been using noted above is not working. It’s a terrible crackling, sounds like an echo, and cuts in/out. Please help!