Tonal portrait of a pipe organ

Abstract

Measurement techniques are described that enable the steady state tone color (timbre) of a musical instrument to be quantified. The system is applied to sounds from the pipe organ in the Great Hall of Sydney University. A one-third octave normalized loudness spectrum that is independent of pitch is derived for each set of notes from selected ranks of pipes. From the normalized spectrum, sharpness and tristimulus coordinates are computed, the latter being independent of both pitch and loudness. Measurements made on different ranks of pipes or made at different times are compared with the aid of spectrum dissimilarity and tristimulus diagrams.