Source spectra for excised and latex phonatory models

Abstract

An excised larynx model and a latex physical model were used to study acoustic spectra of the phonatory source as a function of subglottal pressure, glottal adduction, and vocal-fold length. A supraglottal vocal tract was not used, indicating that the acoustic signal corresponded to the output glottal flow. Each model was mounted over an -inch tracheal tube through which flowed pressurized, heated, and humidified air. The subglottal pressure and EGG signal (excised model) were recorded on a personal computer. The mean flow rate, mean subglottal pressure, and SPL were recorded manually, and adduction was specified by the use of interarytenoid shims. The output audio signals from the larynx models were recorded on a DAT recorder. Spectral information of the audio signal was obtained via FFT analysis (Matlab). Preliminary data indicate that the spectral slope did not have a constant dB/octave rate, and spectral slope had a primary dependence on subglottal pressure and a secondary dependence on adduction. Other acoustic details and the differences between the two models will be discussed. [Work supported by NIDCD Grant Number DC03566.]