Distorted audio, internal speakers

[Johnny Calvara]

Next time you look at the logic board and speakers, see if you can trace the connection from each speaker to a device on the Mac (not necessarily the logic board) and also see if you can trace the connection to the headphone jack. However, if this is a multi-layer board which is likely, that may be difficult if not impossible.
And maybe take some good clear photographs.
I'm trying to determine why you don't get the distortion via the headphone jack and which power IC, if in fact there is one, drives the speakers.

I'll open it up, hopefully today after working outside (homegrown organic veggies come before Mac speakers). I'll post photos.

As for Boom 2, I removed it and related files and it made no difference whatsoever.

 

[Johnny Calvara]

Well, the computer pretty much died. The sound became worse and started to be affected also on bluetooth and headphones. Then the computer started freezing at times and not booting up at times. Pulling one of the RAM cards helped, but since I found myself in the US I bought a MacBook Air M1. Thanks to everyone for the help.