strange audio issues

When it gets close to 80 degrees outside my entire audio system begins to first crackle, then goes out. A good cool night and it is back on until the heat begins to rise again.

This is a 2010 Prius 3, with satellite and cd. the screen is active during all this, but the way, including updated scores of ballgames on Sirius xm. Just no sound.

I've heard it could be the amp. Anyone else with this issue that can shed some light?