There is disclosed a system (20) for processing sound signals for use in a hearing prosthesis, the system comprising a transducer (1) for converting a sound signal into an electrical signal (30). A first. processor (4) for processing said electrical signal (30) into a plurality of frequency channel signals, each channel signal having an amplitude envelope to define at least one set of channel outputs (40, 41). A second processor (5) for obtaining information relating to a fundamental frequency of the electrical Signal (30). A third processor (6) for obtaining information relating to the harmonic nature of the electrical signal (30). A modulator (7) for modulating the at least one set of channel outputs (40, 41) received from the first processor (4) in accordance with the in formation relating to the fundamental frequency and the harmonic nature of, the electrical signal so as to generate at least one modified set of channel outputs (70, 71). A selector (8) for selecting one or more channels from the at least one modified set of channel outputs (70, 71) so as to define at least one or more channels for electrical stimulation together with the magnitude of said electrical stimulation and generating a stimulation signal (80, 81) in accordance therewith, A transmitter (10) for transmitting said stimulation signal for application by said hearing prosthesis (11).
