SOUND TRANSMISSION LOSS or TRANSMISSION LOSS (TL)
A measure of the reduction in magnitude of SOUND INTENSITY in a TRANSMISSION system.
The loss due to geometric spreading (see SOUND PROPAGATION) is called divergence loss. By implication, transmission loss is also a measure of SOUND INSULATION in a structure. It is calculated from the equation:
TL = 10 log10 (1/s) (dB)
where s is the SOUND TRANSMISSION COEFFICIENT.
See: SOUND TRANSMISSION CLASS. Compare: ABSORPTION COEFFICIENT, NOISE REDUCTION COEFFICIENT, REFLECTION COEFFICIENT.