Sound processing processes and sound processing units are disclosed. The processes and units have particular application to auditory prostheses. In an embodiment, after input sound signals are processed into channels, an algorithm is applied to selectively increase the modulation depth of the envelope signals. In another embodiment, a sound processing unit includes a filter bank configured to process a sound signal to generate envelope signals in each of a plurality of spaced frequency channels. The speech processing unit also includes a broadband envelope detector configured to measure the envelope of at least one broadband signal, and a channel modulation module configured to use the at least one broadband envelope signal to modulate the channel envelope signals to generate modulated envelope signals.
