Sound & Acoustics
What is sound & acoustics?
Sound is an energy that travels through a medium, usually air. This energy is known as acoustical energy. We can hear sound as these pressure fluctuations cause our eardrums to vibrate. These usually minute changes in atmospheric pressure are referred to as sound pressure and the fluctuations in pressure as sound waves. Sound waves are produced by a vibrating body, be it a guitar string, loudspeaker cone or jet engine.
The vibrating sound source causes a disturbance to the surrounding air molecules, causing them bounce off each other with a force proportional to the disturbance. The energy of their interaction creates ripples of more dense (higher pressure) to less dense (lower pressure) air molecules. When the molecules are pushed closer together it is called compression; when they are pulled apart, it is called rarefaction. The back and forth oscillation of pressure produces a sound waves.