An implantable stimulation arrangement is described for generating electrode stimulation signals for an implanted electrode array having stimulation electrodes. A filter bank pre-processor processes an input acoustic audio signal to generate band pass signals each corresponding to an associated band of audio frequencies. A signal envelope module computes a corresponding signal envelope for each band pass signal. A stimulation pulse generator extracts stimulation signal information from the rate of change of the signal envelopes such as a time-based derivative to generate stimulation event signals defining electrode stimulation timings and amplitudes for some or all of the stimulation electrodes.
