FIG. 1.

(Color online) Vowel space of stimuli. First formant frequencies are shown on the ordinate and second formant frequencies are on the abscissa. Formants shown were measured at the midpoint of each vowel. Shaded areas indicate manipulated frequency regions. Male talker vowels are enclosed in diamonds and female talker vowels are in rectangles. Plots show that the formant frequencies for each vowel are different between the male and female speaker and vocoder conditions will therefore affect male and female vowels in different ways. Note that the apical frequency region does not cover the first formants of all vowels, and the middle and basal regions each cover the second formants of approximately half the vowels. The basal region also covers the third formant of all vowels (not shown).