Sound wave basics | What is Sound
This page describes sound wave basics and sound wave types.It also mentions Hi-Fi Sound and Hi-Qu Sound terms.
Sound: It is a form of energy which can be experienced by human ears. Sound waves are propagated in the form of vibration of j-medium particles. Sound waves can not be propagated in the absence of a medium.
Velocity of sound is about 332 meters per second (in the dry air) and it is about 1450 meters per second (in the water). Frequency range of sound waves produced by man and musical instruments range between 30 Hz to 12 KHz.
There are various means by which sound can be stored and will be played back when needed.
Types of Sound Waves
There are three main types of sound waves viz. Infrasonic waves, Ultrasonic waves and audible waves.
Infrasonic sound waves:
The waves having a frequency of less than 20 Hz is known as Infrasonic sound waves.
Ultrasonic sound waves:
The Waves having frequency of more than 20 KHz are known as ultrasonic sound waves. These waves are used for communications, to determine depth of sea, to increase agriculture yields, to improve quality of seeds etc.
Audible sound waves:
Waves which can be heard by human ears are called audible waves. The frequency range for this waves extend from 20 Hz to 20 KHz. This range may vary person to person based on age.
Hi-Fi stands for High Fidelity. Sound available at the output of a loudspeaker or a headphone which contains all the fundamental as well as harmonic frequencies (of the input signal applied ) is called Hi-Fi sound.
Hi-Qu stands for High Quality. Sound available at the output of a loudspeaker or a headphone which is free from all sorts of distortion is called as Hi-Qu sound.
Unit of Measurement of Sound
The intensity of sound wave in comparison to another one is measured using
logarithmic unit referred as 'Decibel'.
dB =10* Log (P2/P1)
Wheer, P1 = intensity of one sound and P2 = intensity of another sound.
Sound can be converted into electrical signal form of digital form with the use of microphone. Refer Microphone basics for more information.
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