Table 1. The sound absorption coefficient at 250, 500, 1,000, and 2,000 Hz and NRC
Thickness (cm)
Sound absorption coefficient @ Frequency (Hz)
NRC
250
500
1,000
2,000
6
0.118
0.167
0.368
0.567
0.305
8
0.136
0.241
0.498
0.647
0.381
10
0.174
0.356
0.543
0.980
0.513
12
0.198
0.438
0.541
0.891
0.517
NRC: noise reduction coefficient.