This document discusses hearing loss corrections and audio equalization. It defines hearing loss and how it is measured using generated sounds at different frequencies. Hearing loss can cause difficulty understanding speech, especially in noisy environments, and affects over 1 billion people worldwide. The document also describes the levels of severity for hearing loss in decibels and statistics on hearing loss in the American population. It notes that hearing aids are used to improve hearing and speech comprehension by magnifying sound vibrations in the ear.

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Multifunction audio filter
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Hearing Loss Corrections
Audio Equalization
With the classical audiometry, seven (or more)
frequencies are considered for each ear:
125, 250, 500, 1000, 2000, 4000 and 8000 Hz
Hearing loss or hearing impairment is a
partial or total inability to hear.
Hearing loss is generally measured by
playing generated or recorded sounds.
Hearing sensitivity varies according to
the frequencies of sounds and can be
plotted on an audiogram.
A person with hearing loss will often be less able to understand speech, especially in noisy
conditions.
This is chiefly true for people who have a sensorineural hearing loss (the common type of
hearing loss, about 90%).
As of 2013, it affects about 1.1 billion people.
It causes disability in more than 5% of the world’s
population (360 to 538 million).
It causes moderate to severe disability in 125 million
people.
Of those with hearing loss, it began for 65 million
people during childhood.
source: Wikipedia.
Severity of hearing loss,
in decibels of hearing loss
or dB HL:
Slight:
16-25 dB HL
Mild for children:
20-40 dB HL
Mild for adults:
26-40 dB HL
Moderate:
41-54 dB HL
Moderately Severe:
55-70 dB HL
Severe:
71-90 db HL
Profound:
91 dbHL or greater
Totally Deaf:
Anacusis
Approximately 15% of
American adults (37.5
million) aged 18 and over
report some trouble hearing.
Approximately 15% of
Americans (26 million
people) between the ages of
20 and 69 have high
frequency hearing loss due to
exposure to noise at work or
during leisure activities.
Among adults aged 70 and
older with hearing loss who
could benefit from hearing
aids, fewer than one in three
(30%) has ever used them.
Even fewer adults aged 20 to
69 (approximately 16%) who
could benefit from wearing
hearing aids have ever used
them.
Source:
National Institute on Deafness
and Other Communication
Disorders (NIDCD)
There is a progressive loss
of ability to hear high
frequencies with aging
known as Presbycusis.
This can start as early as 25
(for man) and 30 (for
woman).
Hearing aids and wireless
hearing aids are service that
work to improve the hearing
and speech comprehension,
generally by magnifying the
sound vibrations in the ear.
20
50
0
10
30
40
60
70
80
90
100
dB
125 250 500 1000 2000 4000 8000Hz