Weird issue. I am trying to play music from the docked iPad through the iPad channel strip. I see signal coming from iTunes in the channel strip itself AND I can get it to play through our monitor sends (AUX 1-3). But, I can't get any signal in the LR mains (no... the mains aren't muted!). Been using the mixer for years as our PA for our band, just never played music through it. Everything else seems to work great. Any thoughts?