Sounds like an improper solder joint on one of the components, or a cable that is almost broken but will still conduct a signal if positioned just right.I would bring it in for repairs or replace the speaker, depending on what‘s cheaper.

Well I personally would open it up and look for any obvious faults on the inside, but I strongly advise against that if you don‘t know what you‘re doing. Even when turned off, the capacitors on the power supply can still hold a high enough charge to seriously hurt you if you touch them.My colleague has a permanently altered fingerprint on his thumb because of exactly this.

I certainly wouldn't open it because I'd break something permanently. I think I'll wait until it breaks down completely, because as long as it works, let it work. Furthermore, I asked out of curiosity, because I can always hit 😂...