AFMG Network Forum

E Aden · Member

I have been an EASE Jr user for quite a while, and have recently upgraded to EASE w/ EARS and AURA. Given the increased options and resolution available for acoustical investigations I am pondering some of the elements within my models.

How does everyone model seating areas? In the past I have used 2D double-sided faces coated to the floor, double sided faces elevated off the floor, single sided faces built into the floor, all with absorption coefficients of course.

Would it be a more accurate representation to construct 3D cubes or large boxes to simulate the entire area?

Does a 2D face with scattering coefficients accurately simulate an actual audience?

Thanks!

Ron Sauro · Member

Eric.... This is a controversial area within the modeling community... I have been involved with EASE since V1.0 or V1.1... Currently we are operating a measurement lab that is measuring speakers for EASE and other programs but one thing we are doing that is not done anywhere else in the world is we measure scattering coefficients in Full scall products. We have measured seats in our laboratory and found they do NOT have a scattering coefficient... The reason is that scattering is a measurement of surface Roughness... when the roughness exceeds a dimension that is beyond 1/16 of the sample size being measured then the scattering coefficient goes away and specular reflection becomes predominate... This then makes the reflections fall into an area that can be modeled gemetrically... So in this case I recommend that you model the seats like pews.... long continuous planes showing the seat itself AND the seat back as a long plane. ... these may float in space in the correct position and will provide the 1st and 2nd order reflections that will cause the majority of your problems....If you have a curved set of seats they will have a tendency to focus the seat back reflections as in real life rather then just randomly distributing the energy in random directions such as the scattering coefficient will do...

This area will change in many ways in the next few years now that we can actually measure these characteristics of materials....The research is ongoing and yields new information daily.
Sauro
NWAA Labs