I had the similar issue with my AV receiver, except that it suddenly developed in my LF speaker.I ignored it for a while, but within a short time more audio problems developed.
I ended upn shipping it back to the distributor for a warrnty repair - some of the circuits had been fried and new parts and circuit boards inserted as replacements.
Speculation is that a sudden power surge (repeated) caused the problems.
FWIW ....
I ended upn shipping it back to the distributor for a warrnty repair - some of the circuits had been fried and new parts and circuit boards inserted as replacements.
Speculation is that a sudden power surge (repeated) caused the problems.
FWIW ....