Why Orchestras Tune to A440
The note an orchestra tunes to was fought over for two centuries, settled by an international conference in 1939 and written into a standard in 1955. Some orchestras still ignore it.
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- What happened
- Concert pitch, the frequency assigned to the note A above middle C, varied widely across Europe until the nineteenth century. An international conference in London in 1939 recommended 440 hertz, and the International Organization for Standardization adopted it as ISO 16 in 1955.
- Why it matters
- Standard pitch lets instruments built anywhere play together and determines how music written centuries ago sounds today. It is a small, clear case of how technical standards get made.
- What remains uncertain
- Some ensembles tune higher for brilliance and period-instrument groups tune lower for historical accuracy, so the standard describes a convention rather than a fact.
Before a concert, an oboist plays a single note and the orchestra tunes to it. That note is an A at 440 vibrations per second, and the reason it is 440 rather than some other number is a story about trade, nationalism and the physics of sound.
A pitch for every city
For most of music's history there was no standard. Pitch was set by whatever organ or tuning fork a town possessed, and it varied by more than a whole tone between cities. As instruments were traded and musicians traveled, the inconsistency became a practical problem, and as pitch crept upward in the nineteenth century in pursuit of a brighter sound, singers complained that parts written for them were becoming unsingable.
Attempts at a standard
France legislated a pitch of 435 hertz in 1859, and several countries followed. Others did not. In 1939 an international conference in London recommended 440 hertz, a figure that had been in use in the United States and had the advantage of being a round number convenient for the electronic oscillators then coming into use for broadcasting. The Second World War interrupted adoption. In 1955 the International Organization for Standardization published ISO 16, 'Acoustics: Standard tuning frequency (Standard musical pitch)', fixing 440 hertz. It was reaffirmed in 1975.
The standard that is not quite standard
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ISO 16 specifies 440 Hz as the standard tuning frequency for the note A above middle C.
Fact · confidence high
- ISO 16:1975 · ISO
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