I don't see an updated materials database available for download...seems that would be nice to have as a crowd-sourced thing or maybe just restricted to official Bose employee generated ones (maybe only the Germans to make sure they're accurate...).
That being said, we're working on a tricky gym and the ends of the bleachers have a vinyl triangular banner thing that deploys with the bleachers.
Anyone have a good idea for absorptive coefficients for this ?
May 20, 2020
thanks for checking in.
We currently have no plans to update the Materials DB. In my personal opinion, there’s so much manufacturer-specific stuff that is also locally very different, it wouldn’t make much sense to me to compile it all. Sure enough, should anybody be interested particularly in German manufacturers, drop me a line and I can check what we have already created in terms of local databases.
The material you asked for is a good example of something you won’t find in a textbook anyway. If I understand your description correctly, then it more or less boils down to some kind of acoustically semi-transparent fabric (porous absorber) in front of a large (non-standard) airspace. An airspace that might also be characterized by some kind of diffuseness: in essence, you have sound going through the fabric, then get exposed to a scattering reflection underneath the bleachers and then the scattered sound travels back through the fabric into the room.
Because of all these combined effects, there’s really no way to model all of them accurately in Modeler. My starting point would probably be a scattering surface with an alpha of like 0.5. Depending on their total size, these surfaces might qualify to be included in RT matching, should any measured RT data be available.
I hope this answer is somehow useful. Pls. let us know if you have any other remarks.
Tks Thomas...I was actually referring to the German Bose employees....we are working on an 'educated guess' for this material and we'll include your input.