DISCRIMINATION OF SINGLE AND COMPLEX CONSONANT-VOWEL-AND VOWEL-CONSONANT-LIKE FORMANT TRANSITIONS

Two discrimination experiments were performed to determine auditory sensitivity for single and complex consonant-vowel (CV)-and vowel-consonant (VC)-like formant transitions. In experiment 1 difference limens in end-point frequency were determined by means of same/different paired comparison tasks for 20-, 30-, and 50-ms second formant (F2) speechlike transitions, followed or preceded by an XO-ms vowel-like steady state in initial or final position, respectively. The F2 transition was either single or part of a multiformant (complex) stimulus, also containing a fixed F1 transition with a steady state, a stationary third formant, and a 20-ms voice bar. Just-noticeable differences in end-point frequency decrease with increasing transition duration in all conditions and are smaller for single transitions than for transitions in a multiformant complex. Although difference limens in end-point frequency increase with increase in frequency extent, they are smaller in final than in initial position. As for relative rate-of-frequency change, the smaller the frequency extent, the larger the difference limens of decrementing transitions, possibly because the end points of the transitions approach the frequency of the steady state. Transitions varying in frequency and duration, in such a way that a constant rate of frequency change is maintained (experiment 2), yield considerably smaller difference limens than those varying in frequency extent at a constant transition duration (experiment 1). Discrimination is affected more by changes in duration than in frequency, even when the total duration of the stimulus remains constant. Both experiments show that transition rate is perceptually less important than end-point frequency or transition duration in discriminating short speechlike transitions. (C) 1995 Acoustical Society of America.