ARMA Modelling for Whispered Speech

The Autoregressive Moving Average(ARMA)model for whispered speech is proposed.Compared with normal speech,whispered speech has no fundamental frequency because of the glottis being semi-opened and turbulent flow being created,and formant shifting exists in the lower frequency region due to the narrowing of the tract in the false vocal fold regions and weak acoustic coupling with the subglottal system.Analysis shows that the effect of the subglottal system is to introduce additional pole-zero pairs into the vocal tract transfer function.Theoretically,the method based on an ARMA process is superior to that based on an AR process in the spectral analysis of the whispered speech.Two methods,the least squared modified Yule-Walker likelihood estimate(LSMY)algorithm and the Frequency-Domain Steiglitz-Mcbride(FDSM)algorithm,are applied to the ARMA model for the whispered speech.The performance evaluation shows that the ARMA model is much more appropriate for representing the whispered speech than the AR model,and the FDSM algorithm provides a more accurate estimation of the whispered speech spectral envelope than the LSMY algorithm with higher computational complexity.