Thanks Paul, I kind of understand all the words, I guess I don’t have enough of a scientific mind to put them all together into the big picture! (As for TV and radio waves that’s another issue but I guess the principles are the same).

I sort of get that but then there are all these different instruments and notes going on at the same time and how are they all fitted into a tiny groove (also have the same problem with the speaker vibrating at different frequencies etc.) Tbf I also have the same problem with tape and digital.