Sound and Audio: Sound is a mechanical energy disturbance which propagates by matter as a wave. Sound is characterized through the various properties that are: frequency, period, wavelength, amplitude and speed or velocity.

Noise and sound frequently mean similar thing but a noise is an unnecessary sound. In engineering and science, noise is an unwanted element that obscures a signal.

Humans perceive sound through the sense of hearing. Through sound, we usually mean the vibrations that travel via air and can be heard through humans. Although, scientists and engineers utilize a wider description of sound that includes low and high frequency vibrations in air which cannot be heard through humans and vibrations which travel by all forms of matter, gases, solids and liquids. The issue that supports sound is termed as the medium.

Sound propagates like waves of alternating pressure, causing local regions of rarefaction and compression. Particles in the medium are displaced through the wave and oscillate as outcome of the displacement. The scientific investigation of sound is termed as acoustics. The sound part of a program or track recorded on a videotape that includes sound, music or narration is termed as Audio.