Method and apparatus in which optical sources deliver light to small specific areas of the cochlea for purposes of stimulation, which brings the advantage of increased spectral fidelity because the stimulation illumination can be more specifically placed than electrical-stimulation signals. In some embodiments, a plurality of light sources or light delivery devices are placed at finely-spaced locations along the cochlea but only a fraction of them are used within any short period of time due to the limitation of power delivery to the optical emitters and a restriction on heat within the cochlea due to the absorption of the optical stimulation signals. The ability to choose which optical sources are used at any given time frame provides the ability to choose the sources that illuminate and thus stimulate the particular small areas of the cochlea that generate nerve signals perceived as the semitone frequencies found in Western music.