When do you hear the buzz? Only on shore power? Only on Bluetooth, or also on other sources? Do you have any fluorescent lighting? Dimmers? LED lighting? Try turning everything on and off and see if you can identify the source. Disconnect shore power and run on battery. You get the idea. Anything that uses power could be the interferer. Turn Bluetooth off on everything but one music source.
Interference problems are difficult to diagnose. Good luck!
"You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
2001 Safari 25 RB Twin (Gone, but not forgotten)
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
WBCCI 1322, TAC FL-39, AIR 82265