Vocal-Tract Perturbation Functions
John M. Heinz · The Journal of the Acoustical Society of America · 1967
In recent years, Webster's horn equation has been widely used as the basis for an approximate description of the acoustic behavior of the human vocal tract. Starting from an assumption of the validity of this equation, a procedure for determining for an arbitrary vocal-tract configuration those first-order changes in the configuration that will effect changes in one and only one formant frequency (or, alternatively, one and only one lip impedance pole or zero) is presented. Examples illustrating the iterative use of this procedure for determining vocal-tract configurations that correspond to specified impedance pole-zero patterns are given together with a discussion of some of the practical difficulties that arise in this application. [This work was supported in part by Special Fellowship from the National Institute of Neurological Diseases and Blindness, Public Health Service while the author was a guest at the Department of Speech Communication, The Royal Institute of Technology, Stockholm, Sweden.]