noise reduction coefficient
A measure of the sound-absorbing efficiency of a material, equal to the average of the absorption coefficients of the material, computed to the nearest 0.05 at four frequencies: 250, 500, 1000 and 2000 Hz. (Ching, 1995)
A measure of the sound-absorbing efficiency of a material, equal to the average of the absorption coefficients of the material, computed to the nearest 0.05 at four frequencies: 250, 500, 1000 and 2000 Hz. (Ching, 1995)