# Sound energy

Sound measurements
Characteristic
Symbol
Sound pressure  p · SPL
Particle velocity  v · SVL
Particle displacement  ξ
Sound intensity  I · SIL
Sound power  P · SWL
Sound energy  W
Sound energy density  w
Sound exposure  E · SEL
Sound energy flux  Q
Acoustic impedance  Z
Speed of sound  c
Audio frequency  AF

Sound energy is a form of energy associated with the vibration or disturbance of matter. Sound is a is a mechanical wave and as such consists physically in oscillatory elastic compression and in oscillatory displacement of in a fluid. Therefore, the medium acts as storage for both potential and kinetic energy as well.[1]

Consequently, the sound energy in a volume of interest is defined as the sum of the potential and kinetic energy densities integrated over that volume:

$W = W_\mathrm{potential} + W_\mathrm{kinetic} = \int_V \frac{p^2}{2 \rho_0 c^2}\, \mathrm{d}V + \int_V \frac{\rho v^2}{2}\, \mathrm{d}V ,$

where: