Where can I find audio of cats purring?
As an experiment, I just tried to record my cat purring with a decent-quality microphone (he’s a very purry fellow, and was sitting on the desk next to the keyboard purring away) and the results were totally for shit. I think the way to go might be to get your hands on a recording stethoscope, apply same to the ribcage of a purring cat, and go from there.
