A method is described for an auditory prosthesis system to generate electrical stimulation signals to stimulation contacts on an outer surface of an implanted electrode array. An input audio signal having a prominent sensed frequency is pre-processed to produce multiple representative frequency band signals. Each of the frequency band signals is then processed to generate corresponding electric stimulation signals for the stimulation contacts. Each of the electric stimulation signals has an associated stimulation frequency, and for at least one of the electric stimulation signals, the stimulation frequency is varied to maintain an integer ratio between the stimulation frequency and the prominent sensed frequency of the input audio signal.