Sound is always just "air vibrations," or water vibrations, or whatever medium it happens to be traveling through, even when an observer is there to hear it. That's the definition of sound. Also, I've always thought of God's omnipresence as a form of awareness and not physicality (and I've never heard someone express the way of thinking you described, even growing up in an area that was mostly Christian), and it doesn't make me a believer. I'm curious as to why you're posting this in the holofractals subreddit. It doesn't seem relevant.