Tracking the time to recovery after induced loudness reduction (L)

In induced loudness reduction (ILR), a strong tone causes the loudness of a subsequently presented weak tone to decrease. The aim of the experiment was to determine the time required for loudness to return to its initial level after ILR. Twenty-four subjects were exposed to 5, 10, 20, or 40 brief bursts of 2500-Hz pure tones at 80-dB SPL (inducers) and then tested in a series of paired comparison trials. Subjects compared the loudness of a weak target (2500 Hz at 60-dB SPL) to the loudness of a comparison tone at 500 Hz previously judged to match the target. The comparison task was repeated until the two tones were again judged equally loud. The results showed that (a) recovery after ILR is a relatively long process with a time scale of minutes, and (b) recovery time increased approximately 20 s with each doubling of the number of inducers.