The auditory threshold was measured for a pair of clicks in the presence of band‐rejected masking noise. This threshold depends on the interval between the two clicks. As the interval is changed, the threshold intensity alternately increases and decreases. For homopolar clicks and masking noise with a spectral gap centered atfHz, maxima are at (2n+1)/(2f) sec (n= 0,1,2,…). Experimental determinations of this fluctuation, for equal‐intensity clicks, are in quantitative agreement with predictions of a simple model. In the model, band‐stop noise produces a band pass filtering of the click stimulus, and the stimulus is detected if the long‐time average energy at the filter output exceeds some threshold value. However, if the clicks are of unequal intensity, the threshold is influenced by the click order. This order effect is inconsistent with the energy‐detection model.