Did You Know? Musical Notes from the Penn State Laureate

January 12, 2009

Q: Why do we tune instruments to an "A" that equals 440 hertz and what does this mean?

A: With hertz (Hz), we are defining the frequency of cycles (sound waves) per second. When an "A" equals 440 Hz, it means that there are 440 cycles per second. Thus, when you hear an "A" as equaling 440 Hz, it means that there are 440 sound waves vibrating your eardrum each second. When the oboe plays the "A" at the beginning of an orchestra concert, is it really 440? In 1939, an international treaty was signed standardizing modern pitch at "A" = 440 Hz. Although this is a standard, it is not always strictly adhered to. Orchestras today may tune to an "A" that is anywhere from about 415 Hz (Baroque ensembles), to 442 Hz (many European orchestras) to 444 Hz (the Boston Symphony). What difference does it make in the sound? The lower the frequency, the lower the pitch and the less bright the sound will be. This means that the strings are less taut, and have more flexibility and warmth. For the higher frequency, (up to 444 Hz), the sound is much brighter and more resistant. Historically, pitch levels have risen gradually, perhaps as a result of competing to produce a brighter or more "brilliant" sound. In the School of Music at Penn State, as in most music schools, we stick to the convention and tune the "A" on our pianos to 440 Hz.

Please send any other musical questions that you always wanted to know but were too shy to ask to Penn State Laureate Kim Cook at kdc3@psu.edu.

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Last Updated November 18, 2010