Effects of glottal termination impedance on formant frequencies and bandwidths
Lou Boves, Bert Cranen · The Journal of the Acoustical Society of America · 1983
The finding that synthetic speech, based on the customary linear model of acoustic speech production, often sounds somewhat machinelike, has motivated various attempts to refine the model. Our approach to the problem concentrates on variations in formant parameters due to the changing termination impedance at the glottis. Open and closed glottis intervals are determined from the electroglottogram that is digitized and recorded together with the speech signal. Linear prediction analysis of the signal segments taken from the closed glottis intervals leads to stable results for both formant frequencies and bandwidths. LP analysis of segments from the open glottis intervals leads to extremely erratic results, which can be proved to be due to pronounced spectral zeros. We will present numerical data on within-cycle formant variations in the speech of adult males obtained from cepstrally smoothed spectra. [Work supported in part by the Dutch Organization for the Advancement of Pure Research Z.W.O.]