Acoustic impedance

Sound measurements
Characteristic
Symbols
 Sound pressure p, SPL, LPA
 Particle velocity v, SVL
 Particle displacement δ
 Sound intensity I, SIL
 Sound power P, SWL, LWA
 Sound energy W
 Sound energy density w
 Sound exposure E, SEL
 Acoustic impedance Z
 Audio frequency AF
 Transmission loss TL

Acoustic impedance and specific acoustic impedance are measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. The SI unit of acoustic impedance is the pascal-second per cubic metre (symbol Pa·s/m3), or in the MKS system the rayl per square metre (Rayl/m2), while that of specific acoustic impedance is the pascal-second per metre (Pa·s/m), or in the MKS system the rayl (Rayl).[1] There is a close analogy with electrical impedance, which measures the opposition that a system presents to the electric current resulting from a voltage applied to the system.

  1. ^ Kinsler L, Frey A, Coppens A, Sanders J (2000). Fundamentals of Acoustics. Hoboken: Wiley. ISBN 0-471-84789-5.