A sound source radiates out sound
waves. These sound waves travel through a medium and arrive at receptors. So there are
three distinct elements in a system of sound:
(i) Source, which produces the
acoustic energy, (e.g loudspeaker).
(ii) Conveying medium, which transmits
the sound, (e.g. air).
(iii) Receptor, which senses the
sound, (e.g. human ear).
sound power in watts.
The strength of a sound can be
described by two methods :
(i) The pressure amplitude, Prms in Pascals or N/m2, which is the
root-mean-square value of the pressure differences.