<Tr> <Td> </Td> <Td> Hearing Loss with Age (Presbycusis) Teenagers begin to lose the ability to hear high - pitched sounds . Beyond the age of 25, many adults cannot hear this 10 - second audio clip at a frequency of 17.4 kHz . </Td> </Tr> <Tr> <Td_colspan="2"> Problems playing this file? See media help . </Td> </Tr> <P> The commonly stated range of human hearing is 20 Hz to 20 kHz . Under ideal laboratory conditions, humans can hear sound as low as 12 Hz and as high as 28 kHz, though the threshold increases sharply at 15 kHz in adults, corresponding to the last auditory channel of the cochlea . Humans are most sensitive to (i.e. able to discern at lowest intensity) frequencies between 2,000 and 5,000 Hz . Individual hearing range varies according to the general condition of a human's ears and nervous system . The range shrinks during life, usually beginning at around age of eight with the upper frequency limit being reduced . Women typically experience a lesser degree of hearing loss than men, with a later onset . Men have approximately 5 to 10 dB greater loss in the upper frequencies by age 40 . </P> <P> Audiograms of human hearing are produced using an audiometer, which presents different frequencies to the subject, usually over calibrated headphones, at specified levels . The levels are weighted with frequency relative to a standard graph known as the minimum audibility curve, which is intended to represent "normal" hearing . The threshold of hearing is set at around 0 phon on the equal - loudness contours (i.e. 20 micropascals, approximately the quietest sound a young healthy human can detect), but is standardised in an ANSI standard to 1 kHz . Standards using different reference levels, give rise to differences in audiograms . The ASA - 1951 standard, for example, used a level of 16.5 dB SPL (sound pressure level) at 1 kHz, whereas the later ANSI - 1969 / ISO - 1963 standard uses 6.5 dB SPL, with a 10 dB correction applied for older people . </P>

Sound waves with frequencies above the normal human range of hearing