Editing Hearing loss (section)

===Hearing standards===

{{See also| Absolute threshold of hearing| Hearing range}}

{{further| Equal-loudness contour| A-weighting}}

Human hearing extends in frequency from 20 to 20,000&nbsp;Hz, and in intensity from 0&nbsp;dB to 120&nbsp;dB HL or more. 0&nbsp;dB does not represent absence of sound, but rather the softest sound an average unimpaired human ear can hear; some people can hear down to −5 or even −10&nbsp;dB.  Sound is generally uncomfortably loud above 90&nbsp;dB and 115&nbsp;dB represents the [[threshold of pain]]. The ear does not hear all frequencies equally well: hearing sensitivity peaks around 3,000&nbsp;Hz.  There are many qualities of human hearing besides frequency range and intensity that cannot easily be measured quantitatively. However, for many practical purposes, normal hearing is defined by a frequency versus intensity graph, or audiogram, charting sensitivity thresholds of hearing at defined frequencies.  Because of the cumulative impact of age and exposure to noise and other acoustic insults, 'typical' hearing may not be normal.<ref>ANSI 7029:2000/BS 6951 Acoustics – Statistical distribution of hearing thresholds as a function of age</ref><ref>ANSI S3.5-1997 Speech Intelligibility Index (SII)</ref>