Pitch music: Encyclopedia II - Pitch music - Need to standardize pitch

Pitch music - Need to standardize pitch

The need to standardize pitch levels, at least within one city or country, rose as performance of music which combined the organ with instrumental ensembles became more popular. One way in which pitch could be controlled was with the use of tuning forks, although even here there was variation - a tuning fork associated with Handel, dating from 1740, is pitched at A = 422.5 Hz, while a later one from 1780 is pitched at A = 409 Hz, almost a semitone lower. Nonetheless, there was a tendency towards the end of the 18th century for the frequency of the A above middle C to be in the range of 400 to 450 Hz.

Throughout the first half of the 19th century, there was a tendency for the pitch used by orchestras to rise. This was probably largely due to orchestras competing with each other, each attempting to fill increasingly large concert halls with a brighter, more "brilliant", sound than that of their rivals. They were helped in this endeavour by the improved durability of the violins' E-strings - in the 16th century, Michael Praetorius had rejected various high pitch standards as leading to snapped strings, but the new strings could take the higher tension without breaking.

The rise in pitch at this time can be seen reflected in tuning forks. A 1815 tuning fork from the Dresden opera house gives A = 423.2 Hz, while one of eleven years later from the same opera house gives A = 435 Hz. At La Scala in Milan, the A above middle C rose as high as 451 Hz.

The most vocal opponents of the upward tendency in pitch were singers, who complained that it was putting a strain on their voices. Largely due to their protestations, the French government passed a law on February 16, 1859 which set the A above middle C at 435 Hz. This was the first attempt to standardize pitch on such a scale, and was known as the diapason normal. It became quite a popular pitch standard outside of France as well.

There were still variations, however. The diapason normal resulted in middle C being tuned at approximately 258.65 Hz. An alternative pitch standard known as philosophical or scientific pitch, which fixed middle C at exactly 256 Hz (that is, 2⁸ Hz), and resulted in the A above it being tuned to approximately 430.54 Hz, gained some popularity due to its mathematical convenience (the frequencies of all the Cs being a power of two). This never received the same official recognition as A = 435, however, and was not as widely used.

In 1939, an international conference recommended that the A above middle C be tuned to 440 Hz. This standard was taken up by the International Organization for Standardization in 1955 (and was reaffirmed by them in 1975) as ISO 16. The difference between this and the diapason normal is due to confusion over which temperature the French standard should be measured at. The initial standard was A = 439 Hz, but this was superseded by A = 440 Hz after complaints that 439 Hz was difficult to reproduce in a laboratory owing to 439 being a prime number.

Despite such confusion, A = 440 Hz is now used virtually world wide, at least in theory. In practice, as orchestras still tune to a note given out by the oboe, rather than to an electronic tuning device (which would be more reliable), and as the oboist himself may not have used such a device to tune in the first place, there is still some variance in the exact pitch used. Solo instruments such as the piano (which an orchestra may tune to if they are playing together) are also not universally tuned to A = 440 Hz. Overall, it is thought that the general trend since the middle of the 20th century has been for standard pitch to rise, though it has certainly been rising far more slowly than it has in the past...

Readers should also consult Helmholtz: 'On the sensations of tone'.

Adapted from the Wikipedia article "Need to standardize pitch", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki