Pitch

What it means

Pitch is that property of a tone that makes it appear high or low. Physically it corresponds to frequency: the more vibrations per second, the higher the tone. Perception, however, follows not the difference but the ratio — a doubling of frequency always yields the octave, regardless of register. This is why all intervals rest on ratios.

In the notation

Pitch is represented spatially: higher on the staff means higher in sound. Which note lies on which line is fixed by the clef; accidentals change it by semitones, ledger lines extend the grid. With transposing instruments, written and sounding pitch diverge, which is why a distinction must be made in scores between the notated and the sounding indication.

Musical use

Two things are practically important. First, the absolute assignment is a convention: concert pitch a' = 440 vibrations per second is fixed, not given by nature, and historically the pitch standard fluctuated considerably — one reason why vocal music of earlier centuries lies, in today's tuning, higher than originally intended.

Second, pitch within a combined sound is not rigid. On instruments with flexible intonation it is oriented by harmonic function: the leading tone is taken close to its goal, the third of a major chord rather low. A G-sharp as a leading tone and an A-flat as a lowered degree are therefore not the same note, even though they coincide on the piano.

With some sounds — bells, many percussion instruments, noises — an unambiguous pitch cannot be determined, because the partials do not lie in whole-number ratios.

Pitch is measured in hertz or designated by note names. Human hearing perceives frequencies roughly between 20 and 20,000 hertz; a smaller range is used musically.

Performance practice

Intonate in context, not in isolation: check every note against a lower reference note and orient yourself by the sound becoming calm. Use beats rather than displays. And with transposing instruments, take care always to name sounding pitches within the ensemble.