Hearing range usually describes the range of frequencies that can be heard by an animal or human, though it can also refer to the range of levels. In humans the audible range of frequencies is usually said to be 20 Hz (cycles per second) to 20 kHz (20,000 Hz), although there is considerable variation between individuals, especially at the high frequency end, where a gradual decline with age is considered normal. Sensitivity also varies a lot with frequency, as shown by equal-loudness contours, which are normally only measured for research purposes, or detailed investigation. Routine investigation for hearing loss usually involves an audiogram which shows threshold levels relative to a standardised norm.
Read more about Hearing Range: Determination of Hearing Thresholds, Land Mammals, Marine Mammals
Famous quotes containing the words hearing and/or range:
“In trying to understand the appeal of best-sellers, it is well to remember that whistles can be made sounding certain notes which are clearly audible to dogs and other of the lower animals, though man is incapable of hearing them.”
—Rebecca West (1892–1983)
“Jane Addams, founder of Hull House, once asked, “How shall we respond to the dreams of youth?” It is a dazzling and elegant question, a question that demands an answer—a range of answers, really, spiraling outward in widening circles.”
—William Ayers, U.S. author. To Teach: The Journey of a Teacher, ch. 7 (1993)