| Frequency (Hz) | 125 | 250 | 500 | 1K | 2K | 4K | NRC | 
|---|---|---|---|---|---|---|---|
| 
													Absorption Coefficients, Type A Mount												 | 
													0.22												 | 
													0.21												 | 
													0.23												 | 
													0.22												 | 
													0.20												 | 
													0.22												 | 
													0.20												 | 
| Frequency (Hz) | 125 | 250 | 500 | 1K | 2K | 4K | 8K | 
|---|---|---|---|---|---|---|---|
| 
													Scattering Coefficients, AES-4id-2001												 | 
													0.0												 | 
													0.002												 | 
													0.012												 | 
													0.056												 | 
													0.779												 | 
													0.877												 | 
													0.691												 | 
| 
													* Unlike sound absorption testing (ASTM C423) and sound transmission testing (ASTM E90), there is no standardized ASTM (American
Society for Testing of Materials) test for sound diffusion. The Audio Engineering Society has suggested guidelines for characterizing
the uniformity of scattering produced by surfaces from predictions of scattered polar responses. These suggestions are from
informational document AES-4id-2001 and has yet to be adopted by ASTM industry use nor does it present a standardized, verifiable
reference for the comparison of products. Currently, diffusion calculations are used for predicting test results and are a product of
each manufacturer’s interpretations. AVL Systems recognizes AES-4id-2001 as a tool for product development and performance
predictions.												 | |||||||