On Loudness Enhancement of a Tone Burst by a Preceding Tone Burst

According to preceding experiments, loudness effects in pairs of tone bursts are controlled by two processes, loudness enhancement and loudness summation. This paper deals with the effects of intensity, time, and frequency differences between the bursts on the loudness enhancement of the second burst. Listeners were asked to match the loudness of a third (comparison) burst to the loudness of the second burst of a monotic burst pair. All three bursts had a duration of 10 msec, and the second and third bursts were at 1000 Hz. The intensity of the first burst was either +20, 0, or −20 dB re the intensity of the second burst, which was always at a sensation level of 40 dB. The interval between the onsets of the first and second bursts was varied stepwise between 10 and 500 msec, and the frequency of the first burst, between 200 and 4000 Hz. The results indicate a loudness enhancement that increases with the intensity of the first burst and decreases as the time interval and the frequency difference between the bursts in the burst pair increase. When the first burst was at an intensity level of −20 dB, a loudness decrement occurred.