JUST NOTICEABLE DIFFERENCES FOR GLOTTAL FLOW WAVE-FORM CHARACTERISTICS

This study was primarily motivated by the need to establish the corres pondence between auditory abilities and laryngeal function. Just notic eable differences (JNDs) were obtained for the open quotient and speed quotient of the glottal flow waveform. The quotients were synthesized for both the glottal flow alone, and for the output pressure signal a fter the glottal now signal was applied to the synthesis vocal tract f or the Vowel /a/. Six adult men and five adult women, all teachers of singing, participated as Listeners. An adaptive auditory listening pro cedure was used to estimate JNDs for the four types of stimuli. The gr oup average JND values were as follows. For the standard open quotient value of .6000, JND = 0.0264 (SD =.010) for the glottal flow and JND = 0.0344 (SD =.020) for the output pressure. For the open quotient, th ere was no statistically significant difference between genders or bet ween the types of signals. For the standard speed quotient value of 2. 000, JND = 0.154 (SD =.043) for the glottal flow and JND = 0.319 (SD = .167) for the output pressure. For the speed quotient, there was no st atistically significant difference between genders, but the difference between types of stimulus (glottal flow versus output pressure) was s ignificant (p <.006). The variance among the JND values was significan t ly larger for the output pressure stimuli compared to the glottal fl ow stimuli for both the open quotient and the speed quotient.