A signal processing scheme for output limitation.

For both normal listeners and mild to moderately sensori-neurally impaired (probable etiology, presbycusis) listeners a summation of discomfort (S) occurs for complex stimuli, proportional to the logarithm of the number of components. Regression equations of S = 2.05 + 11.51 log n for normals and S = 3.95 + 12.88 log n for hearing impaired (where n equals the number of components or bandwidth in the complex) were found to be significantly different. This change in percept with increased bandwidth (or components) has not been satisfactorily explained in terms of power or amplitude peak density of the stimuli. The regression equations could be applied to future digital hearing aids so that maximum output levels (MPO) would account for this summation.