The purpose of this study is to determine if individuals with residual low-frequency hearing in the severe range can develop improved speech perception by combining their residual acoustic hearing with electrical processing through a cochlear implant designed to stimulate the high-frequency basal and middle turn of the cochlea while preserving useful low-frequency acoustic hearing. To accomplish this, we propose to implant individuals with severe hearing with a Cochlear® Nucleus™ Hybrid L24 Implant or a Cochlear® Nucleus™ Hybrid S12 in the poorer ear. We believe these devices will do less damage to the Organ of Corti structures, than longer, more invasive standard cochlear implant electrodes.