What does architect provide for acoustical prediction?

[Daniel Postilnik]

Hi gents,

Assuming I have access to some acoustical prediction software, generally what is the type of file I would request from an Architect in order to simulate the dispersion of sound in a room given a certain number of boxes with a certain coverage pattern hung at a certain position? Thanks.

 

[Randy Pence]

Re: What does architect provide for acoustical prediction?

Hi gents,

Assuming I have access to some acoustical prediction software, generally what is the type of file I would request from an Architect in order to simulate the dispersion of sound in a room given a certain number of boxes with a certain coverage pattern hung at a certain position? Thanks.

dxf, dwg, pdf, jpg, a napkin - anything which gives you the dimensions of the room, which you would then build a new model with with whichever drafting software your prediction software uses. A proper architectural drawing provides far more detail than necessary.

 

[Ivan Beaver]

Re: What does architect provide for acoustical prediction?

Hi gents,

Assuming I have access to some acoustical prediction software, generally what is the type of file I would request from an Architect in order to simulate the dispersion of sound in a room given a certain number of boxes with a certain coverage pattern hung at a certain position? Thanks.

Randy nailed it.

However it is VERY important to realize what the preduiction can and can't provide.

how high of a freq do you want to predict to? You need ot model to at least (at a minimum) 1/2 wavelength. So if you only want to go to 2Khz (not very high) you will need to model everything 3" or larger. That is A LOT of detail that most people do not even attempt to do.

The other thing is the data available for your wall materials. The specs that are available are generally assuming an incident angle of 90°. So when sound strikes the panel at a different angle (which is most of the case) the data is invalid.

Just things you have to consider. The results you get are only as good as the data that is inputed-on all fronts.

You also need to careful of the data of the loudspeakers used. There are a number of products that have values for 1/3rd oct 5 degree polars. However they are not actually measured that way. A lot of 1 oct 10 degree data is actually measured, and then the averages between each of next points are used as the 1/3rd 5° values. Which is not the actual data.

And then some data is just "smoothed" to look better than it actually is.

You really have to dig a bit deeper sometimes.

 

[Grant Conklin]

Re: What does architect provide for acoustical prediction?

Hi gents,

Assuming I have access to some acoustical prediction software, generally what is the type of file I would request from an Architect in order to simulate the dispersion of sound in a room given a certain number of boxes with a certain coverage pattern hung at a certain position? Thanks.

Depends what prediction software you're using. I believe EASE will import Google Sketchup files. I typically redraw in LARA.

Grant

 

[Daniel Postilnik]

Re: What does architect provide for acoustical prediction?

Ivan, this is all really helpful info, but the level of detail you're talking about is way beyond what the client would require. Really they want to see that our setup will reach a maximum of audience positions in an "ideal" situation. It seems that the free program (GPA/Ray-end) might be the way to go.

 

[Ivan Beaver]

Re: What does architect provide for acoustical prediction?

Ivan, this is all really helpful info, but the level of detail you're talking about is way beyond what the client would require. Really they want to see that our setup will reach a maximum of audience positions in an "ideal" situation. It seems that the free program (GPA/Ray-end) might be the way to go.

Then you are not talking about acoustical prediction, but rather a simple coverage map.

Those are VERY VERY different animals-with lots of difference in skill needed and accuracy in prediction.

HOWEVER- you need to be sure to use a 3D model. As far as I know (the last time checked anyway) the GPA was only a 2D model. As such, it will only predict what will happen if the loudspeakers are in the same plane as the audience. Not usually the case with an install in which the speakers are up in the air (a different plane.). If I am wrong on the availability of a GPA 3D model I appologize.

You will also need to be sure the data for the particular loudspeaker choice is available in the particular model you want to use.

Not all loudspeakers with the same "specs" have the same coverage maps.

 

[Brad Weber]

Re: What does architect provide for acoustical prediction?

If all you care to model is the direct coverage then do you really care about the room? If you're just looking at direct coverage then unless you have architectural elements that might interfere with the direct sound path, the purpose of the room drawings would basically be to identify the audience areas and where you could put speakers. You could model the listener areas and the speakers relative to those, anything beyond that would be required only if you want to assess the effect of the room/environment or to make it look pretty.

It is interesting how many people build elaborate models and then only look at the direct sound (and often without interference considered).

 

[Ivan Beaver]

Re: What does architect provide for acoustical prediction?

If all you care to model is the direct coverage then do you really care about the room? If you're just looking at direct coverage then unless you have architectural elements that might interfere with the direct sound path, the purpose of the room drawings would basically be to identify the audience areas and where you could put speakers. You could model the listener areas and the speakers relative to those, anything beyond that would be required only if you want to assess the effect of the room/environment or to make it look pretty.

It is interesting how many people build elaborate models and then only look at the direct sound (and often without interference considered).

An often overlooked element in so many different aspects.

"what am I here to do". or WHat do I want to know from a particular model/measurement etc.

Knowing what you want to know-really helps to know the approach in what you are doing.

The tools are there-but using wrong-they really don't do much good.