This cookie is set by GDPR Cookie Consent plugin. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category 'Functional'. The cookie is used to store the user consent for the cookies in the category 'Analytics'. These cookies ensure basic functionalities and security features of the website, anonymously. Necessary cookies are absolutely essential for the website to function properly. Since noise is also a sound, the terms noise and sound are synonymously used and are followed in this module. Sounds of frequencies less than 20 HZ are called infrasonic and greater than 20,0000 HZ are called ultrasonic.

The discrimination and differentiation between sound and noise also depends upon the habit and interest of the person/species receiving it, the ambient conditions and impact of the sound generated during that particular duration of time. Since it is unwanted sound, we call it noise. For example, the typical cry of a child produces sound, which is mostly unfavourable to normal hearing.

Noise may be of high frequency or of low frequency which is undesired for a normal hearing. This transmission path is usually the atmosphere through which the sound is propagated, but can include the structural materials of any building containing the receiver.

The frequency limits of audibility are from 20 HZ to 20,000 HZ.A noise problems generally consists of three inter-related elements- the source, the receiver and the transmission path.

Noise pollution control device