Figure 17.

Results of a forward-masking experiment investigating the perception of spectral shape by a multiple-channel cochlear implant user (McKay, 2004). The masking stimulus was chosen to simulate the output of the SPEAK sound-processing scheme for an input signal derived from the sound of the violoncello. In the experimental version of SPEAK, six electrodes were activated representing the frequency bands containing the highest levels; the corresponding stimulation levels are displayed as the vertical columns at electrode positions shown along the abscissa. The forward-masked thresholds, plotted as a proportion of the electrical dynamic range of each electrode on the ordinate, are shown as points connected by a line. The error bars represent plus and minus one standard error of the mean.