Perceptual judgments of roughness as influenced by second formant frequency

The role of tongue height and position and their acoustic influence upon judgments of glottal roughness has been the source of several investigations. The purpose of this study was to investigate the effect of second formant frequency positions on listener judgments of roughness. An electrical analog of the larynx (LADIC) was used to simulate a laryngea source. The output of LADIC was fed into a vocal tract analog and all center formant frequencies were held constant with the exception of the second formant frequency, which was varied from 1000 to 1800 Hz in 200 Hz steps. The signals were recorded on magnetic tape and arranged in a paired-comparisons and a rating scale design. The listeners were asked to make judgments of roughness. Variations in the second formant under neither procedure appeared to be related to listener perceptions of roughness. However, certain significant differences were observed and it is suggested that the reader go to the results and discussion section where it was explained that significant results were probably spurious. Results from this study did not demonstrate that varying the second formant is of importance in the perception of roughness.