NRC (Noise Reduction Coefficient) is the average of a material's sound absorption at 250, 500, 1,000 and 2,000 Hz, rounded to the nearest 0.05. It is measured under ASTM C423. 0 means everything reflects; 1.00 means nearly everything is absorbed. Panels can exceed 1.00 because their edges absorb sound too.
| Material | NRC |
|---|---|
| Painted concrete | 0.00–0.05 |
| Drywall | 0.05 |
| Carpet on pad | 0.30 |
| Mineral fiber ceiling tile | 0.55–0.70 |
| 1 in fabric panel | 0.80 |
| 2 in fabric panel | 1.00 |
| 4 in fabric panel | 1.15 |