Restructuring speech representations using STRAIGHT-TEMPO: Possible role of a repetitive structure in sounds

A set of simple new procedures has been developed to enable the real-time manipulation of speech parameters. The proposed method uses pitch-adaptive spectral analysis combined with a surface reconstruction method in the time-frequency region, and an excitation source design based on phase manipulation. The proposed procedures preserve the details of time-frequency surfaces while almost perfectly removing ne structures due to signal periodicity. This close-to-perfect separation allows for over 600% manipulation of such speech parameters as pitch, vocal tract length, and speaking rate, without further degradation due to the parameter manipulation. Consequently, the proposed method is an ideal tool for investigating the perceptual correlates of acoustic speech parameters.