Perceptual dimensionality of jitter and shimmer in synthetic vowels
Anton J. Rozsypal, B. Millar · The Journal of the Acoustical Society of America · 1975
Dimensionality of the perceptual space of synthetic vowels /a/, /u/, and /i/ with different amount of jitter (randomness in vocal period) and shimmer (randomness in vocal amplitude) was investigated. Using the method of paired comparisons, the subjects were instructed to select the more human-like vowel sound in each pair. The preference data was analysed using an analysis of variance and multi-dimensional scaling techniques. The results support the observation that some degree of roughness is necessary for vowels to be perceived as natural. The multi-dimensional scaling yielded a two-dimensional solution which was not readily interpretable in terms of the signal parameters.