I have little pads that I have made of the textured vinyl shelfpaper, cut to the size (or a bit larger) of my iPhone. I just lay the phone on that pad, and I hear it vibrate, but just whatever noise it makes without the amplification of the main surface, and the phone doesn't move on that pad. The vinyl shelf-liner is something I use for a lot of different tasks, mainly to control movement on "slide-y" surfaces. I've got a (now old) 2TB external spinner HD with an aluminum enclosure. The pad cuts down the constant hum-m-m from that hard drive--just one example.