Setting the Temperament Octave in Piano Tuning

The system of tuning that is the accepted standard today for setting the temperament octave is that of "equal temperament". Since 500 B.C. the scientific study of intervals and pitch has gone through several stages of development until today keyboard instruments are tuned to equal temperament.

This means that all of the 12 tones of an octave, say F below middle C to F above middle C, are equally spaced in the chromatic scale. In order to accomplish this it is impossible to have perfect 5ths, 4ths, 3rds, 6ths, etc. These intervals need to be adjusted slightly out of tune, ie. not quite perfect, so that it will be possible to play the instrument in all 12 keys.

The piano technician must learn to hear the different intervals & determine by how much to set them "out of tune" so that all the semi-tones in the octave are an equal distance apart. This first octave set in the middle of the keyboard forms the foundation for tuning the rest of the piano.

Most technicians use the octave F to F as their temperament octave but some prefer to tune from A to A. It really does not matter which method is used. The results are basically the same.