Topmusicanswers
I've known that for a long time but what I did not know was that the Treaty of Versailles contained, among many other things of course, the first modern attempt to standardize musical pitch. It standardized the A above middle C at 435 Hertz, not 440, but we'll get back to that.
Why is 440 Hz concert pitch?
This standard was taken up by the International Organization for Standardization in 1955 (reaffirmed by them in 1975) as ISO 16. It is designated A4 in scientific pitch notation because it occurs in the octave that starts with the fourth C key on a standard 88-key piano keyboard.
What frequency is concert A?
Since 1939 the standard for the concert A in the United States, and thereby concert pitch, has been 440 Hz, or 440 vibrations per second, and 440 Hz is the most widely accepted industry standard throughout the world when one looks to musical instrument designs.
What note does A concert band tune to?
If you ever played in concert band, you'll remember that you always tuned to B flat. This is because most of the band instruments are actually pitched in B flat, and so this is their natural tuning note.
