AFMG Network Forum

Vanesa · Member

Hello EASE Community!

I'm trying to find out the ways I can display how a good a room "mixes" sound with EASE.

For this I've started with a very simple example, a shoebox 7 x 7 x 3 m with all surfaces sound reflective (5 % absorption). I've set an audience area at 1,20 m height covering all the floor surface and a "sphere" loudspeaker in the center of the room at 1,60 m height.

I run then an AURA simulation with "intermediate resolution" and "long window" (to get the "aftermath" of long lingering reflections). I proceed then to inspect the T30 expecting to obtain a distribution with a considerable variation along the audience area (this is the epitome of a non mixing room, right?). To my surprise this doesn't happen as I expect since the T30 distribution barely varies.

There come my questions:

- Am I tackling this from the wrong perspective? It might be that it is easier to see this with other parameters than T30 or TSPL, or even that the room proportions aren't representative?

- What do you consider an acceptable T30 deviation in a room? After some literature and measurement standars research I couldn't find any specific values.

- Another way I can think about this is to compare the statistical Sabine value and the one obtained with AURA... but still, which would you consider and acceptable deviation?

Some food for your thought Smile

Lindsay S · Member

I think part of it is that reverberation is defined as a diffuse field that is consistent throughout the space. There will be variations but in a simple box they probably won't be significant. What does significantly vary are early order reflections which have an enormous impact on acoustic quality. So, while I'm not sure what you are trying to show, reverberation time variance by location in a simple space is not going to tell you much.

Lindsay Smith
Seattle

Vanesa · Member

Lindsay, thanks a lot for your reply!

What I'm trying is to compare how the positioning of absorptive materials in a room affects the distribution of the sound field. Therefore I start from an empty, all reflective situation, in order to test differente ceiling, floor and wall configurations.

If reverberation is defined as a diffuse field that is consistent throughout the space, which is the point of a ray tracing calculation? Do you maybe mean reverberation time statistical formulae (like Sabine and Eyring)?

Your are right, in such a simple box variations apparently aren't significant. I'll take a look at the early order reflections then!