Sensorineural hearing loss involves not only a reduction of sensitivity to sound as measured by the audiometric threshold, but also a predictable distortion of the perception of loudness growth.  As the amount of threshold hearing loss increases, so does the proportion of abnormal loudness growth.  This phenomenon is called recruitment. 

Peak Clipping

 Compression circuits attempt to partially correct for this by amplifying loud and soft sounds by different amounts.  When used for output limiting, compression is less distorting than peak clipping as seen by the demo's on the left.

Compression