Chosen Solution
Recently I was cleaning my MacBook and changing its thermal paste. After I finished, I recognised, that the speakers sounds bad and I’m afraid, that there could be some more issues, that I didn’t recognise. What should I do, to check it all?
Did you try running the onboard diagnostics? Restart you system and press the D key? But that is still limited to the core elements. Reference: Mac startup key combinations Beyond that it would take someone with deeper skills to figure things out.
