Absolute threshold of hearing
The absolute threshold of hearing (ATH) is the minimum loudness of a pure tone that an average ear with normal hearing can hear with no other sound present. The absolute threshold relates to the sound that can just be heard by the organism. This is also known as the auditory threshold.
The threshold of hearing in humans is 20 µPa (micropascals) = 2×10−5 pascal (Pa). The tympanic membrane of the ear operates as a sound pressure sensor, as does a microphone
Psychophysical methods for measuring thresholds
Measurement of the absolute hearing threshold provides some basic information about our auditory system. The tools used to collect such information are called psychophysical methods.
Role of frequency
Because human hearing is more sensitive to some frequency bands than others, thresholds vary depending on the frequency of the stimulus tone.
Absolute Threshold Of Hearing Media
Average hearing thresholds in decibels (SPL) (the unit of 'dB(HL)' shown on the vertical axis is incorrect) are plotted from 125 to 8000 Hz for younger (18-30 year olds, red circles) and older adults (60-67 year olds, black diamonds). The hearing of older adults is shown to be significantly less sensitive than that of younger adults at frequencies of 4000 and 8000 Hz, corresponding approximately to the piano keys and tones of b′′′′ (B7) and b′′′′′ (B8), respectively.
