Loudness as a Function of Duration

Loudness is measured for 500-, 300-, 100-, 30-, and 10-msec tones at 1000 cps in 5 subjects with clinically normal hearing to determine the nature of temporal summation above the threshold of audibility. The results from numerical-magnitude-balance experiments showed that the form and slope of the loudness function at 1000 cps does not change as a function of duration, at least between 500 and 10 msec. The absolute difference among the numerical-magnitude-balance functions was determined by magnitude production. These results showed that the intensity increase required for equal loudness as a function of duration is the same as that required for the detection of identical tones at the threshold of audibility. The combined results of the foregoing experiments indicate that the growth of loudness as a function of duration is constant for sensation levels greater than 40 dB; and, at sensation levels less than 40 dB, there is a progressive increase in the rate of growth of loudness with a decrease in sensation level. [This research was performed at the Laboratory of Sensory Communication, Syracuse University, Syracuse, New York 13210.]