The mechanism of sound production in organ pipes and cavity resonators

Abstract

A new unified method of treating the sounding mechanism of organ pipes and cavity resonators replaces the control volume method which until recently has been the most widely accepted theory. It is shown that shear layers contain a dividing surface whose motions control the production of sound in the resonant cavity. Both jet-drive and force drive contributions are found to be involved in the sounding mechanism. The present approach shows the drive system to be inherently linear over a range of shear layer widths, so that sinusoidal oscillation is readily achievable. For voicing situations calling for spectra rich in harmonics, nonlinear drive is attained by resorting to a smaller ratio of jet width to lip cutup which, at high enough Reynolds number, permits the growth of eddies which result in impulsive action at the lip. © 1992, Acoustical Society of Japan. All rights reserved.