Discrimination of frequency‐glide direction

Abstract

It is often assumed that the relevant information in formant transitions includes the direction as well as the extent of frequency excursions. A study to determine the ability of listeners with normal hearing to determine the direction of linear frequency modulation of sinusoidal tones has been devised. To more closely approximate the listener's task in processing speech, music, or other environmentally important sounds, the initial frequency of each transition was selected at random from within a predefined range. Thus, for each interval of a 2Q, 2AFC listening task, the listener hears a frequency glide of the same duration and extent. In one of the two middle intervals, the direction of the transition is reversed to produce the “signal.” Since each of the four glides begins and ends on frequencies selected at random, the listener cannot rely on simple pitch differences to determine which interval contained the reversed glide. Our preliminary results will be discussed, with emphasis on the effect of the width of the “roving frequency” range on listener performance. [Work supported by a grant from AFOSR.]