An implantable device includes a multi-channel electrode array in which each channel is associated with an electrode in the array. An audio processing stage processes an input audio signal to produce output channel signals representing associated bands of audio frequencies. A timing and envelope detector processes the output channel signals in a sequence of sampling intervals, including, for each sampling interval, determining for each output channel signal a set of pulse timing requests. A pulse selection amplitude definition stage determines for each set of requested pulse timings a set of output pulses at specified times and amplitudes selected from the set of requested pulse timings based on a pulse selection inhibition function.