@Joannie - i have been playing my piano tonight (piano man is coming tomorrow to give it a final going-over) and found the tuning has already slipped by half a note, which got me interested to see what I can find on U-Tube etc.
Anyway, I checked the internet to find out what a correct 'middle-A' sounds like - and found all sorts of wonderful things.
Apparently even Alzheimers can be improved by subjecting patients to sound therapy for a set period of time per day, it helps people have a restful sleep, it is even useful in calming ADHD children. The magical number is the 40 HZ Effect.Please inform yourself, Joannie - - seems one need only to have the sound switched on, but best is when it comes via ear phones.
I have only listened to that now for 10 minutes, and can say, that it quietens that inner voice and I feel relaxed. I am certainly going to use it, when I know how to do it without turning the computer on, as I have a large screen, sitting on a desk in my office - so not mobile. Maybe I'll get myself a tablet.
(and I plan to use it for language learning and getting chores done) - and have a friend whose wife has Alzheimers, will let him know, too.
Good night
Taurisk