What is sound?
Sound is caused by the vibration of an object – as is clearly visible in the movements of a loudspeaker cone. The surrounding air is compressed at intervals, thus creating a sound wave. The loudness of sound is related to the extent of that compression and the resulting degree of pressure of the sound wave. This is measured in decibels [dB]. After making a correction for the perception of the human ear, the level is given as dB(A). The scale runs from the faintest sound the human ear can perceive: “0 dB (A)” to a maximum of 180 dB(A), the noise emanating from a launching pad when a rocket is launched. Decibels are a logarithmic number. This means that if the dB number increases by 10, the intensity of the sound increases “tenfold”.