278
C. Drug˘ a et al.
Sound features of which the most important are:
• Frequency or pitch, this is the fundamental frequency and is measured in Hertz
(Hz), unit of measurement illustrating the number of cycles or waves produced in
one second.
• Amplitude or grit, this is the power of sound, that is, the way we perceive a sound:
weaker or louder. It is measured in decibels (dB).
• Timber represents the harmonic spectrum made from higher than fundamental
sounds also called harmonics [1].
The simplest type of sound wave is sinusoidal wave. Sinusoidal pure waves rarely
exist in nature, but they are useful because all other sounds can be divided into combinations of sinusoidal waves [2]. Human ears are remarkably sensitive to vibration
in the air. The human hearing threshold is about 20 micro pascal (µPa), which is an
extremely small amount of atmospheric pressure. At the other extreme, the strongest
sound that a person can withstand without pain or ear damage is about 120 dB (20 Pa)
[2]. Hearing or hearing perception is the ability to perceive sound by detecting vibrations and environmental pressures over time through an organ such as the ear [3].
Thus, vibrations in the environment are received by the ear and transformed into
nerve impulses that reach the brain and are decoded, resulting in hearing sensation.
Hearing serves a range of functions such as: speaking, alerting you to potentially
dangerous events that appear outside of the field of vision, and serving an esthetic
function such as appreciation of music or nature. Loss of hearing is when your ability
to hear is low, it is also known as hearing or hearing impairment. The wider impact of
hearing loss can therefore be profound, with consequences on the social, functional
and psychological well-being of the person [4].
Audiology is the field and branch of medicine that studies hearing, balance, and
pathological conditions that can affect them. As a health care profession, audiology
refers to all ages, from children to the elderly, and to the evaluation, management,
and therapeutic rehabilitation of those with hearing problems, balance problems,
or those with tinnitus [5]. The modern audiology industry dates back to the end
of the Second World War, when the loss of hearing-related fights was widespread.
Acoustic trauma from high-intensity artillery and the noise of firearms have been
common causes of hearing loss [6]. Audiometry is a branch of audiology and is
the science of measuring auditory acuity for variations in intensity, pitch, and purity,
involving different thresholds and frequencies. Typically, audiometric tests determine
the audible level of the subject with an audiometer, but it can also measure the
ability to discern different sound intensities, recognize pitch, or distinguish between
background noise and noise. Acoustic reflexes and rotational emissions can also be
measured. The results of audiometric tests are used to diagnose hearing loss or ear
disease and often use an audiogram [7]. A pure tone audiometry test measures the
smallest or least audible sound a person can hear. During the test, you will wear
earphones, and you will hear a series of sounds directed at each ear. The amplitude
of the sound is measured in decibels (dB). A whisper is about 20 dB, strong music
varies between 80 and 120 dB, and a response engine is about 180 dB. The tone
C. Drug˘ a et al.
Sound features of which the most important are:
• Frequency or pitch, this is the fundamental frequency and is measured in Hertz
(Hz), unit of measurement illustrating the number of cycles or waves produced in
one second.
• Amplitude or grit, this is the power of sound, that is, the way we perceive a sound:
weaker or louder. It is measured in decibels (dB).
• Timber represents the harmonic spectrum made from higher than fundamental
sounds also called harmonics [1].
The simplest type of sound wave is sinusoidal wave. Sinusoidal pure waves rarely
exist in nature, but they are useful because all other sounds can be divided into combinations of sinusoidal waves [2]. Human ears are remarkably sensitive to vibration
in the air. The human hearing threshold is about 20 micro pascal (µPa), which is an
extremely small amount of atmospheric pressure. At the other extreme, the strongest
sound that a person can withstand without pain or ear damage is about 120 dB (20 Pa)
[2]. Hearing or hearing perception is the ability to perceive sound by detecting vibrations and environmental pressures over time through an organ such as the ear [3].
Thus, vibrations in the environment are received by the ear and transformed into
nerve impulses that reach the brain and are decoded, resulting in hearing sensation.
Hearing serves a range of functions such as: speaking, alerting you to potentially
dangerous events that appear outside of the field of vision, and serving an esthetic
function such as appreciation of music or nature. Loss of hearing is when your ability
to hear is low, it is also known as hearing or hearing impairment. The wider impact of
hearing loss can therefore be profound, with consequences on the social, functional
and psychological well-being of the person [4].
Audiology is the field and branch of medicine that studies hearing, balance, and
pathological conditions that can affect them. As a health care profession, audiology
refers to all ages, from children to the elderly, and to the evaluation, management,
and therapeutic rehabilitation of those with hearing problems, balance problems,
or those with tinnitus [5]. The modern audiology industry dates back to the end
of the Second World War, when the loss of hearing-related fights was widespread.
Acoustic trauma from high-intensity artillery and the noise of firearms have been
common causes of hearing loss [6]. Audiometry is a branch of audiology and is
the science of measuring auditory acuity for variations in intensity, pitch, and purity,
involving different thresholds and frequencies. Typically, audiometric tests determine
the audible level of the subject with an audiometer, but it can also measure the
ability to discern different sound intensities, recognize pitch, or distinguish between
background noise and noise. Acoustic reflexes and rotational emissions can also be
measured. The results of audiometric tests are used to diagnose hearing loss or ear
disease and often use an audiogram [7]. A pure tone audiometry test measures the
smallest or least audible sound a person can hear. During the test, you will wear
earphones, and you will hear a series of sounds directed at each ear. The amplitude
of the sound is measured in decibels (dB). A whisper is about 20 dB, strong music
varies between 80 and 120 dB, and a response engine is about 180 dB. The tone