Music Engineering, 2nd Edition

2

Good Vibrations – The nature of sound

The physics of sound

Sound waves are pressure variations in the physical atmosphere. When I speak, the sound I make creates a series of compressions and expansions in the air immediately around me. These travel away at about 300 metres per second (700 mph) in the form of waves which spread out like ripples on a pond. If I’m talking to myself – a pastime hardly to be recommended – these waves collide with the walls, chairs, tables – whatever – and make them move ever so slightly. The waves are thus turned into heat and ‘disappear’. If there is anyone there to hear me, that part of the wave which impinges on their external ear will travel down their auditory canal and cause their eardrum to move slightly. ...