I have never ever heard of an iOS device picking up radio waves?? Not saying it can't happen just has yet to happen to anyone I know. How is it possible for an iPhone to pick up radio waves just curious? It definitly sounded like background music from radio waves but I just assumed it couldn't be.
Just because you've never heard of it, doesn't mean it can't happen if the conditions are perfect.
I heard music on my computer speakers and it happened maybe twice. The conditions were probably just right and the frequency was picked up by the metal in the speakers. It was so fait that I had to put my ear up to the speaker to even hear it. It's amazing I even heard it at all, but I had my head by the speaker while I was reaching for something and I was like "What the..."
I've never heard of it happening on an iPad, but that's what sounds like happened to you. Just because it hasn't happened to me, doesn't mean it couldn't have happened to you. You know?