I am musician and I know that people dont know nothing.....440Hz is basic freq of tone C which is using for tuning all musical instruments. Original was 432 but it was changed during second world war. So if I play same song and my guitar is tuned from base 440 or 432, you will not hear the difference, it is only 8 hertz difference...People like to talk and teach but they dont know nothing, they just teach what they have been read and never do experiments on their own. I made a lot of experiments in terms of 432hz and I know many things and I always see that people dont know nothing, exept some musicians or devoted experts