Transmission loss (duct acoustics)

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

Transmission loss (TL) in duct acoustics describes the acoustic performances of a muffler-like system. It is frequently used in the industry areas such as muffler manufacturers and NVH (noise, vibration and harshness) department of automobile manufacturers, and in academic studies. Generally the higher transmission loss of a system it has, the better it will perform in terms of noise cancellation.