A=440 was Tuning

[david at piano.plus.com]

Another thing is that from time to time one comes across customers who
bring out an old tuning fork. They're never at the right pitch. They have
the note stamped on them, but not the frequency, and it's never concert
pitch!

I  came across a website that has a nice 440Hz tone, with a great
demonstration of beats between 440, 441 and 442. It's at:
http://www.indiana.edu/~emusic/acoustics/phase.htm

Bottom of the page has the demo.  I did wonder whether different sound
cards might affect the accuracy, but I've tried it on several computers
and get identical results.

Best regards,

David.