Sound – where does it come from?

Illustration of sound being generated when a person is speakingA sound is created when the particles in a medium (usually air in our world) are set moving and forced out of a state of rest. This happens, for example, when we speak. Our vocal chords produce audible pressure variations (high and low pressure) in the air. Sound travels in air at a speed of approximately 340 metres per second. It spreads like a wave and is a mechanical vibration.  

Room acoustics are about the way in which sound behaves in a room. Sound transmission, sound absorption, sound reflection and sound diffusion are all aspects that are important here.

Room acoustics also include how we as humans perceive different acoustic phenomena. The field of building acoustics covers sound insulation too, where the route that the sound takes from one room to other areas is included.