Cluster Analysis of Differential Spectral Envelopes on Emotional Speech

This paper reports on the analysis of the spectral variation of emotional speech. Spectral envelopes of time aligned speech frames are compared between emotionally neutral and active utterances. Statistics are computed over the resulting differential spectral envelopes for each phoneme. Finally, these statistics are classified using agglomerative hierarchical clustering and a measure of dissimilarity between statistical distributions and the resulting clusters are analysed. The results show that there are systematic changes in spectral envelopes when going from neutral to sad or happy speech, and those changes depend on the valence of the emotional content (negative, positive) as well as on the phonetic properties of the sounds such as voicing and place of articulation.