How Sounds Can Be Heard By Humans

sward (57)in #steemiteducation • 7 years ago

The frequency of sounds that can be heard by humans between 20 Hz - 20,000 Hz, sounds that are in this frequency range is called the audio comic. The sound that has frequencies less than 20 Hz is called Infrasonic and sounds that have frequencies greater than 20 000 Hz are called ultrasonics.

Hearing range describes the range of frequencies that can be heard by humans or other animals, though it can also refer to the range of levels. The human range is commonly given as 20 to 20,000 Hz, though there is considerable variation between individuals, especially at high frequencies, and a gradual loss of sensitivity to higher frequencies with age is considered normal. [1]

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Crickets can hear an infrasonic sound, which is why crickets can hear human footsteps from a great distance. Dogs, dolphins and bats can also hear infrasonic sounds. Bats can produce ultrasonic sounds. The ultrasonic sound is reflected by objects around the bat so that it can avoid collisions and determine the position of its prey.

Ultrasonic sounds are used for industry. Example: ultrasonic waves are used to stir the milk to flatten, sterilize the food in cans and flatten the iron mixed with tin that is melted

The Tone is a sound that has a certain frequency. Tone sources can come from our throbbing vocal cords that can produce melodious tones. In addition, strings and guitars are also a source of tones. All objects that vibrate on the audio frequency are the source of the tone. The sound tone depends on the frequency or wavelength.

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Once the speed of propagation is known, the frequency of the sound produced by the string can be calculated. The speed of propagation of a wave is equal to the wavelength.[2]

The higher the frequency or the shorter the wavelength the higher the sound tone. The strong (loud) sound depends on the amplitude: the greater the amplitude the stronger (louder) the sound. The tone (frequency) of the string is influenced by 4 factors, namely:

The length of the string: the shorter the string the higher the frequency.
Sectional area: the thinner the string the higher the frequency.
Tension strings: the higher the strings the higher the frequency.
Mass type: the lighter the string the higher the frequency.

The natural frequency of an air tube depends on the wavelength of the air column: the longer the air column the higher the frequency. The natural frequency of the tuning Darfur depends on the length of the arm: the longer the arm its higher the frequency. Resonance is to follow the vibration of an object when another object near it is vibrated.

The requirement of resonance is the frequency of the object vibrating equals the natural frequency of the vibrating object.

The sound has three properties, namely high-low sound, strong sound, and the colour of sound. The high low sound is a sound wave condition received by the human ear based on frequency (the amount of vibration/second).

High sound (pitch) shows the nature of the sound that characterizes the height or lowness of an observer. This property is related to the frequency, but not the same. Violent sound also affects the pitch. Up to 1,000 Hz, increased violence leads to lower pitches. The Sound waves are limited by the range of frequencies that can stimulate the ear and the human brain to the sensation of hearing.

The amplitude is the maximum deviation, ie the farthest wavelength from the equilibrium point. The intensity indicates the extent to which the sound can be heard. If the intensity is small, the sound will weaken and cannot be heard.

However, when the intensity is large, the sound is stronger, making it harmful to the hearing aid. To know the relationship between amplitude and tone strength can be known by experimenting using tuning fork.

The tuning fork is hit on the table with two different blows, resulting in a hard blow producing a stronger sound. This shows that the amplitude of the vibrations that occur is greater.

Thus, it can be concluded that the strength or weakness of the tone or sound depends on the magnitude of the amplitude. The greater the amplitude of the vibration, the stronger the sound produced. The colour of the sound is the sound received by the hearing device based on its vibration source.

Different vibration sources will produce different sound waveforms. This causes the same tone of two different vibration sources in the human ear.

The tone is a regular frequency sound, such as the sound of various musical instruments. The height of the tone depends on the frequency, while the strong tone depends on the amplitude.

Mersenne's laws govern the construction and operation of string instruments, such as pianos and harps, which must accommodate the total tension force required to keep the strings at the proper pitch. Lower strings are thicker, thus having a greater mass per unit length. They typically have lower tension. Higher-pitched strings typically are thinner, have higher tension, and may be shorter. "This result does not differ substantially from Galileo's, yet it is rightly known as Mersenne's law," because Mersenne physically proved their truth through experiments (while Galileo considered their proof impossible). [3]

Francis physicist named Marsenne investigated the relationship of frequencies generated by strings vibrating with the length of the string, the cross section of strings, the tension and the type of strings. The tool used Marsanne is sonometer.

The Factors that affect the natural tone frequency of a string

The length of the string, the longer the string the lower the resulting frequency.
Sectional area, the larger the cross-section of the string the lower the frequency generated.
The strings, the greater the string voltage the higher the frequency generated.
The mass of the strings, the smaller the strings the higher the frequency the resulting.

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Each harmonic results in an additional node and antinode, and an additional half of a wave within the string. If the number of waves in a string is known, then an equation relating the wavelength of the standing wave pattern to the length of the string can be algebraically derived. [4]

Mathematically, the law of Marsenne is written:
Information :
f = frequency or tone (Hz)
l = string length (m)
F = string voltage (N)
A = the cross-sectional area of the string (m)
λ = string wavelength (m)

The sound of regular frequency is called the tone
The tone is produced by musical instruments. The sounds of irregular frequencies are called sighs, minerals of wind, waterfalls, and waves. There is also a very short sound, but sometimes very strongly called a datum, like the sound of guns, guns and bombs.

The high tone depends on the frequency, the greater the frequency, the higher the tone. Marsenne Francis physicists have investigated the law that applies to striking chords by using a sonometer. Sonometer is a tool used to investigate the high-low tones, a wooden box equipped with a string that can be changed.