Human event related potentials (ERP) were taken using averaging techniques to tonal pulses with systematically varied onset ramp. The rate at which the tonal pulse grows to full amplitude (ramp) was linear on both signal onset and offset. Auditory evoked potentials (AEP), were taken on seven naive college sophomores, with demonstrated normal hearing (ISO, 1964), for onset ramps of 50, 150, 500, 1500, and 5000 msec and a no-signal condition. Offset was 50 msec for all signal conditions. Equipment, calibiation, between-subject variation, and noise considerations required that 64 trials be averaged to achieve useful (approx. 8:1) SIN ratios. Trials consisted of 5.05-sec signal condition to 45-dB sensation level full amplitude and 9.95-sec intertrial interval. Visual analyses indicate that onset ramp affects offset AEP progressively less for all signal conditions as ramp duration increases. Onset ramp associated AEP is not apparent beyond the 150-msec condition. Stepwise correlational analyses are being performed to clarify the apparent dichotomous onset/offset results.