That is what I want to do. I want to solo a channel and see what each instrument looks like on the screen.
Greg, that is exactly what that link shows me doing. It is really helpful. I also use the app to look at a sound system response with pink noise by walking around the room, not for intense tuning, just relative response.
Looks like a left off the list the USB dock camera kit to go from usb->dock.
iPad RTA app- I use AudioTools & Smaart Tools 1, I think around $80.00 for both
Hosa YPP118 headphone Y adapter cable, $5
Hosa CMS105 1/8" trs to 1/4" trs $5
Griffin iMic 1/8" in to USB out $25
iPad Gen 2,3
Apple USB camera kit, usb->dock $30