Soft sounds give the ear inadequate access to rapid amplitude changes in speech

Evidence

Gap detection thresholds decrease (improve) with increasing sound level, but only for low-level sounds. Once a moderate level is reached, stimulus level has little effect on gap detection thresholds. Poor gap detection at low levels may suggest a necessity to present stimuli well above auditory threshold in order to give the ear full access to the temporal variations present in stimuli. For example, speech presented near threshold, or even at 20 dB SL, may not provide sufficient representation of the temporal variations in everyday sounds. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 989

Categorization

• XREF: Directly relevant to the reader’s impairment questions: explains listening effort for those with elevated thresholds.