Objective and subjective evaluations of pipe organ sound

Abstract

Study of correlations between the perceptual and the physical attributes of musical sound is an important part of musical acoustics. This paper will review the status of this field, with particular attention to the pipe organ sound. The pipe organ is an ideal subject for such studies: the sound is simple enough for a study to be feasible, yet complex enough for the study to be interesting. A procedure for systematic measurements and evaluation of many aspects of the organ sound will be described. An interactive, PC-based system enables an efficient yet precise measurement of the fundamental frequencies, spectra of the partials, as well as of the nonharmonic component of all the pipes in an organ, and the transient behavior of selected pipes. Results are presented in a compact and easily understandable form: a ‘‘fingerprint’’ of the instrument. The main room acoustics measurements are also made. The emphasis is on the old but still intriguing question: what imperfections are necessary for achieving the perception of perfection (e.g., small but desirable irregularities in tuning, and in the scaling behavior). If the planned organ concert indeed takes place, measurements of the organ(s) will be made, and the results will be available.