It sounds like you’ve got a wire issue. Meaning that somewhere you’ve got a wire backwards, or touching together. To fix: Check all connections and make sure that the wires match at both the receiver and the speakers – meaning that the negative is to negative, and the positive is to positive.Check to make sure that all the bare wire is wound tightly before going into the speaker wire terminals and that no bear wire is out touching. Also make sure that you haven’t got more than an inch of bare wire stripped, this can also cause a problem.This happens to a lot of people, and most of the time is has to do with a wire being backwards. What happens is when the power increases – like you said for loud volumes, the system “clips” and power goes back to the receiver because wires are “out of phase” (flipped), or touching.
Hope this helps.