Sound - Introdcution
Sound is a wave form which arises due to pressure created on an object, which manifests as vibration.
Properties of Sound:
The fundamental properties that define sound are
Wavelength: Sound waves have large wavelength compared to electromagnetic radiations such as light. The wavelength of audible speechranges from 3.3cm to 3.3m.Since this is in the size of majority of earthly objects, it can travel around the objectsof lesser length without being blocked or attenuated.
Frequency:The number of cycles the wave undergoes in a second represents the frequency, measured in the unit of Hertz. Sound waves in the audible range of humans are generally known as sonic vibrations,having a frequency range of 20 to 18000 Hertz. The rangebelow 20Hz is known as infrasonic and thatabove 18000Hzis known as ultrasonic. The lowest frequency produced by any vibrating body is known as the fundamental or first harmonic.
Amplitude:The amplitude is the maximum displacement of the vibrating object. This is measured in decibels (dB).
Speed: The speed of sound in any medium is directly proportional to the square root ofpressure and inversely proportional to the density of the medium. Typical values of speed of sound in different media are
The objects travelling faster than the speed of sound in the given medium are termed as supersonic.
Production:
Sound is primarily produced by making an object to vibrate. Vibration of strings in a Violin or air column in a flute produce sounds. Animals create sound by vibrating the vocal chords in their throat.The frequency of the sound can be controlled by manipulating the length of the vibrating column.
Propagation:
Sound iscarried awayfrom its producer through a medium which has the ability to vibrate in the direction of travel as the sound waves. Commercial transmission of sound is done after converting the sound waves into electric signal of equal magnitude and frequency by means of a microphone. If the medium moves in the direction of sound propagation, like air, it is called longitudinal wave. If it moves perpendicular to the propagating direction, as in case of water, it is known as transverse wave.
Reception:
Sound waves are sensed when they set the receiving surface to vibrate, for instance the tympanic membrane inside the human ear. Commercially the transmitted electric signals are converted back to sound using a loudspeaker.
The quality of sound depends largely on the rate of vibration of the body as well as the ability of the medium to vibrate along with the sound waves. If the receiver is in a different medium than the sound source, it can be received at a higher or lower frequency due to the difference in speed of sound.
Properties of Sound:
The fundamental properties that define sound are
Wavelength: Sound waves have large wavelength compared to electromagnetic radiations such as light. The wavelength of audible speechranges from 3.3cm to 3.3m.Since this is in the size of majority of earthly objects, it can travel around the objectsof lesser length without being blocked or attenuated.
Frequency:The number of cycles the wave undergoes in a second represents the frequency, measured in the unit of Hertz. Sound waves in the audible range of humans are generally known as sonic vibrations,having a frequency range of 20 to 18000 Hertz. The rangebelow 20Hz is known as infrasonic and thatabove 18000Hzis known as ultrasonic. The lowest frequency produced by any vibrating body is known as the fundamental or first harmonic.
Amplitude:The amplitude is the maximum displacement of the vibrating object. This is measured in decibels (dB).
Speed: The speed of sound in any medium is directly proportional to the square root ofpressure and inversely proportional to the density of the medium. Typical values of speed of sound in different media are
- air – 331 m/s
- water – 1447 m/s
- solids – upto 5000 m/s
The objects travelling faster than the speed of sound in the given medium are termed as supersonic.
Production:
Sound is primarily produced by making an object to vibrate. Vibration of strings in a Violin or air column in a flute produce sounds. Animals create sound by vibrating the vocal chords in their throat.The frequency of the sound can be controlled by manipulating the length of the vibrating column.
Propagation:
Sound iscarried awayfrom its producer through a medium which has the ability to vibrate in the direction of travel as the sound waves. Commercial transmission of sound is done after converting the sound waves into electric signal of equal magnitude and frequency by means of a microphone. If the medium moves in the direction of sound propagation, like air, it is called longitudinal wave. If it moves perpendicular to the propagating direction, as in case of water, it is known as transverse wave.
Reception:
Sound waves are sensed when they set the receiving surface to vibrate, for instance the tympanic membrane inside the human ear. Commercially the transmitted electric signals are converted back to sound using a loudspeaker.
The quality of sound depends largely on the rate of vibration of the body as well as the ability of the medium to vibrate along with the sound waves. If the receiver is in a different medium than the sound source, it can be received at a higher or lower frequency due to the difference in speed of sound.
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