The great 440 Hz conspiracy, and why all our music is ‘wrong’ | Principia Scientific Intl.
“In 1953, a worldwide agreement was signed. Signatories declared that middle “A” on the piano be forevermore tuned to exactly 440 Hz. This frequency became the standard ISO-16 reference for tuning all musical instruments based on the chromatic scale, the one most often used for music in the West. All the other notes are tuned…