From what I understand there is some amount of current that flows from the receiver to the subwoofer. You’re just adding another wire which is enough to power the LED. To put a Rapberry Pi in the middle of all that would seem like overkill to me. Or at least enough that I wouldn’t want to bother with it.
From what I understand there is some amount of current that flows from the receiver to the subwoofer. You’re just…