In Brief:
Effects of varying the input range characteristics of the Nucleus 24 cochlear implant system were evaluated with 12 subjects. Increasing the microphone input sensitivity (sensitivity control [SC]) by 10.5 dB lowered sound field thresholds by this amount, significantly improved the perception of vowels and consonants presented at 40 and 55 dB SPL, and had no adverse effect on the perception of sentences presented in babble at 65 dB SPL. An increase of 8 to 10 dB in the instantaneous input dynamic range (base level) gave some improvement in the perception of consonants, no improvement for vowels, and the mean score for sentences presented in babble was significantly reduced. To achieve better recognition of low-level stimuli, SC settings higher than the default of 8 are needed. For these higher settings to provide loudness comfort for the individual recipient in everyday life, it is necessary to adjust other parameters, such as map C levels, automatic sensitivity control, and base level.