ASA 125th Meeting Ottawa 1993 May

3pMU6. Dichotic beats of mistuned consonances.

M. Patrick Feeney

Edward M. Burns

Dept. of Speech and Hear. Sci., JG-15, Univ. of Washington, Seattle, WA 98195

Temporal envelope perception, aural harmonics, and combination tones have all been proposed as mechanisms to explain the beats of mistuned consonances (BMC). This study used dichotic presentation of mistuned octaves to explore a between-channel temporal explanation. A 2I-2AFC procedure was employed to determine subjects' ability to detect BMC. Masking in dichotically complementary frequency regions was used to eliminate effects caused by aural harmonics and acoustic crossover. Subjects were able to detect dichotic BMC under these conditions. Performance deteriorated with an increase in fundamental frequency as expected from previous studies on monotic BMC and on binaural beats. Envelopes of pairs of beating sinusoids were used to further explore the temporal basis of BMC. Subjects were able to detect mistuned consonant envelopes for both monaural and dichotic presentation. A third experiment examined the detection of the ``sweep-tone'' pitch effect using the same stimuli. The results of these experiments will be discussed in terms of within- and between-channel phase perception. [Research supported by the Virginia Merrill--Bloedel Hearing Research Center, University of Washington.]