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Individual hearing range varies according to the general condition of a human's ears and nervous system. The range shrinks during life, [11] usually beginning at around the age of eight with the upper frequency limit being reduced. Women lose their hearing somewhat less often than men. This is due to a lot of social and external factors.
The human auditory system is sensitive to frequencies from about 20 Hz to a maximum of around 20,000 Hz, although the upper hearing limit decreases with age. Within this range, the human ear is most sensitive between 2 and 5 kHz , largely due to the resonance of the ear canal and the transfer function of the ossicles of the middle ear.
For example, aging typically leads to hearing thresholds which get poorer as test frequencies get higher. [10] Noise induced hearing loss is typically characterized by a "notch" in the audiogram, with the poorest threshold occurring between 3000 and 6000 Hz (most often 4000 Hz) and better thresholds at lower and higher frequencies.
This is not the best threshold found for all subjects, under ideal test conditions, which is represented by around 0 phon or the threshold of hearing on the equal-loudness contours, but is standardised in an ANSI standard to a level somewhat higher at 1 kHz . There are several definitions of the minimal audibility curve, defined in different ...
The absolute threshold of hearing (ATH), also known as the absolute hearing threshold or auditory threshold, is the minimum sound level of a pure tone that an average human 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.
Hearing impairment is defined by the World Health Organization (WHO) as a hearing loss with thresholds higher than 25db in one or both ears. The degree of hearing loss is classified as mild, moderate, severe or profound. [16] The results of pure-tone audiometry are however a very good indicator of hearing impairment.
FAA employees received an email late Thursday — just one day after the fatal collision — from the Office of Personnel Management encouraging them to seek ‘higher productivity’ jobs in the ...
Porpoises have the highest known upper hearing limit at around 160 kHz. [27] Several types of fish can detect ultrasound. In the order Clupeiformes, members of the subfamily Alosinae have been shown to be able to detect sounds up to 180 kHz, while the other subfamilies (e.g. herrings) can hear only up to 4 kHz. [28]