Sound Absorption Coefficients per ASTM C-423-66
| Octave Band Frequency | 2 | 3 | 4 | 5 | 6 | 7 | NRC |
| Center Frequency (Hz) | 125 | 250 | 500 | 1000 | 2000 | 4000 | ---- |
| Absorption Coefficients | |||||||
|---|---|---|---|---|---|---|---|
| Noiseblock (STL) - 2" | 0.15 | 0.66 | 1.07 | 1.06 | 0.97 | 0.86 | 0.95 |
| Noiseblock (STL) - 4" | 0.60 | 1.13 | 1.12 | 1.09 | 1.03 | 0.91 | 1.00 |
| Noiseblock (HTL) - 4" | 0.60 | 1.13 | 1.12 | 1.09 | 1.03 | 0.91 | 1.00 |
Sound Transmission Loss per ASTN E90-70
| Octave Band Frequency | 2 | 3 | 4 | 5 | 6 | 7 | STC |
| Center Frequency (Hz) | 125 | 250 | 500 | 1000 | 2000 | 4000 | ---- |
| Transmission Loss | |||||||
|---|---|---|---|---|---|---|---|
| Noiseblock (STL) - 2" | 17 | 23 | 34 | 47 | 55 | 57 | 37 |
| Noiseblock (STL) - 4" | 21 | 28 | 39 | 48 | 56 | 58 | 40 |
| Noiseblock (HTL) - 4" | 27 | 34 | 48 | 61 | 66 | 70 | 48 |