Materials, Building Components and Structure Testing
ISO-354 & ASTM-C-423
NWAA Labs tests for absortion coefficient using both the ISO-354 and the ASTM-C-423 standards. The results are then delivered to the customer as a detailed report along with a chart of coefficients and a graphic display.
Scattering Coefficient is defined as the result of subtracting the specular reflected energy from the total reflected energy.
Diffusion Coefficient is a measure of the "quality" of the diffuse field and Scattering Coefficient is a measure of the "quantity".
Our clients insist that the scattering data NWAA Labs has already delivered to such companies as Armstrong World Industries, MBI, Pyrok,Wenger Corporation, and Auralex Acoustics has provided insight into their products' performance -- and that allows for not only finer-tuned development, but also better informed marketing and business decision making.
NWAA Labs has earned a reputation for developing innovative and ground-breaking methods for the testing of acoustic parameters. As a result of inquiries, we found that only one or two academic labs in the world were conducting small scale experiments with scattering coefficients. NWAA Labs has a reverberation chamber that is fortunately one of the only chambers in the world large enough to comply fully with the ISO-17497-1 Scattering Coefficient standard. Because of this serendipity, and the innovative mindset of Ron Sauro, we decided to offer "FULL SCALE" ISO-17497-1 Scattering Coefficient testing to manufacturers and users of acoustic materials world wide. Even though no one had yet offered clients full scale testing previously, NWAA Labs broke through the obstacles that invariably occur when moving from small-scale theory to real-life results. After many long and repeated experimentations, a corrected technique was developed to accurately and consistently perform these tests.
The answer is that most of the simulation programs used for acoustics use coefficients to model sound fields in a more correct way. Until now, the programs were "tweaked" by knowledgable users by adding a "scattering coefficient" or "absorption coefficient" based on experience.
Only scattering and absorption are used in simulation programs at this time.
Even though NWAA Labs normally uses the more prosaic test procedures described, the unique perspective and obsessive attention to detail taken by NWAA Labs' Ron Sauro in dealing with test preparation, has unearthed even more innovations in approach -- and even some discoveries that very well may shock the entire acoustics industry! More information -- and techncial presentations at conferences -- will be following soon!