Gain Dependent Expansion strives to reduce the gain for low intensity background signals while maintaining as many of the important soft speech cues as possible.  The amount of gain prescribed in each frequency determines the ratio of the Expansion to Linear segments.

When less gain is prescribed, more expansion is desireable to reduce low-intensity signals that might be audible with better hearing.  In frequencies that require more gain where the hearing loss is more severe, it is crucial to preserve as much of the signal as possible; the expansion segment is much smaller.