Discrimination of the Silent Gap in Two‐Tone Sequences of Different Frequencies

Pairs of two‐tone sequences were presented in such a way that listeners could adjust the time interval separating the onsets of the two tones in the second pair, so that the gap or rhythmic repetitiveness appeared to be the same in the second as in the first pair. The pairs consisted of two 20‐msec tone bursts with 2.5‐msec rise time and 10‐msec fall time. The time interval separating the onsets of the tones in the first, or standard, pair was 40 msec. Responses were observed as a function of the frequency of the fourth tone, the standard pair being of one frequency (1 kHz), while the variable pair began at the same frequency but ended with a different one. As the frequency difference increases up to 250 Hz, the time interval in the variable pair for apparent equality of gap decreases, as does the variability in judgments. Beyond a difference of 250 Hz, both quantities increase. These results are consistent with those of earlier time discrimination experiments [P. L. Divenyi, J. Acoust. Soc. Amer. 49, 127 (1971)] and may relate to the time required to shift the listening band from one frequency to another.