Somehow, it's not happening anymore. I did actually take the EQ out of the signal path before when it was happening continuously, and still did it.. Weird thing that I think possibly had something to do with : the fuse for the front left channel (speaker channel in question) wasn't blown, but was very very slightly split. I replaced it and now all seems good. Anyhow, I took out all the speakers and checked the connections and re-secured them. I think it's ok. I'll keep testing and see what happens! Really appreciate the help!