We use a Yorkville MP8dx PA system, and we are now having problems with it having a loud "POP" at times while we play. It only seems to happen when someone sings through the mic. We've tried setting the levels lower, etc, but nothing works. The levels are no where near maxed, and we cannot figure it out. My best guess is that something is loose inside the mixer, as it started the first time we played after moving our equipment to a new practice facility. Any ideas?