Using Sound to Read Discs, instead of EMRs.
I was just reading a bit on the disc reading. It was only then that this idea of using sound to read discs struck me. We know that sound too, behaves like light, in many situations(has a particular speed limit, both exhibit resonance, etc.). One very important difference being that light is an emr, while sound is a mechanical wave.
Infact, sound is not affected by magnetic or electric field. So now, why is it that we are not using sound to read discs? Or is it that this idea is already being researched, and not much progress had been made yet?
(NOTE: I am a new user, hence if any changes are to be made in the way i've posted this thread, kindly send me a msg)