Noise that is a function of a mechanical contact with, or by, a moving object.
"I had an old 8 track that you converted to CD for me. I LOVE IT. I was so afraid you wouldn't be able to do it because the 8 track was quite old and I hadn't played it in years and years. But the CD came out great. In fact, I'm listening to it right now. The group was some friends of ours from years ago that played together locally in a band. ..."