The evaluation of spectre-temporal receptive fields in auditory neurons makes use of a correlation technique that needs a high amount of calculation time. We present a method in which 2-ms time bins of post-stimulus time histograms, rather than every action potential, are the basis for correlation with the acoustic spectrum of the stimulus. In a t test the content of each bin is classified as excitatory, inhibitory or responseless. The bin width is adjusted to the temporal resolution of the units as determined in a gap detection analysis. The method presented here saves a substantial amount of analysis time and reveals adequately spectre-temporal receptive fields.