iPad is just a control device. It can't create crackling in the speaker. Almost anything you can do on the iPad can also be done using the TV screen interface. It's just easier access on the iPad.\n\nAll crackling sounds were generated as a result using the internal Denon amps thru the right Height 1 and Height 2 speaker terminals on the 4500.\n\n\nI might disagree it's just a control device....it may have different controls. That's why I'm wondering about consistency with regard to app vs avr only and what information that could possibly yield (it could be nothing). I'd exhaust various scenarios before trying some dumb customer service rep on a phone....bounce it off folk here first certainly.