You only have ONE speaker hooked up? I don't know if it can tell what's available. I've never run it without anywhere for the signal to go. I don't use the amps in the 4ES therefore no speaker connections. I do use the eight preouts. I have all kinds of gadgets hooked up to the thing and its auto function works perfectly. I'd have to check my settings. It's been a long time since I paid any attention to them.