A signal processing arrangement generates electrode stimulation signals to stimulation contacts in a cochlear implant electrode array. A signal filter bank transforms an input sound signal into band pass signals, which each represent an associated frequency band of audio frequencies. An envelope processing module processes the band pass signals in a sequence of sampling time frames, wherein for each time frame, the processing includes calculating for each band pass signal at least one signal envelope dynamic property that is changing during the time frame. A channel selection module selects one or more of the band pass signals for each time frame based on the dynamic properties to produce the electrode stimulation signals to the stimulation contacts.