Soundproofing glossary definition of Acoustic impedance

Acoustic impedance :

Z=R+jX ; [ML-4T-1] ; mks acoustic ohm *(Pa.s/m3) ---of a surface, for a given frequency, the complex quotient obtained when the sound pressure averaged over the surface is divided by the volume velocity through the surface. The real and imaginary components are called, respectively, acoustic resistance and acoustic reactance.