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Author Topic: 3D sub prediction software  (Read 2500 times)

Darren Scaresbrook

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3D sub prediction software
« on: December 25, 2013, 11:50:06 pm »

Any suggestions for a 3D modelling software for subs? Needs to be able to include boundaries in the predictions also.

Cheers,
          Darren

Ivan Beaver

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Re: 3D sub prediction software
« Reply #1 on: December 26, 2013, 08:34:57 am »

Any suggestions for a 3D modelling software for subs? Needs to be able to include boundaries in the predictions also.

Cheers,
          Darren
There are a couple of issues with that.

First you need to have polar data for the subs.  Not many manufacturers have this-because there are limited programs to use it in.

Programs such as EASE only model down to 100Hz-not exactly sub territory.

Other programs that have boundaries are only 2D.

The data for the boundaries in the 2D programs is also suspect.  They assume a perfect reflector-which all walls are not.  They flex at different freq so they can also act as absorbers to an extent. I am not sure how much data there is for walls and such below 100hz-since nobody has it in a modeling program.

Danley DDT models subs in 3D-but is limited to Danley subs.  But for now does not have reflective boundaries in the 3D version (2D has boundaries).

There may be some programs that will do this in the future.

But as with any modeling program-the model is only as accurate as the data that is put in-ie how well you build the model.

So for now (as far as I am aware of) you are up to a lot of "guesswork" and experience and possibly looking at plan and elevation view of 2D models to attempt to get an idea of what is happening.
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Mac Kerr

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Re: 3D sub prediction software
« Reply #2 on: December 26, 2013, 11:38:41 am »

There are a couple of issues with that.

First you need to have polar data for the subs.  Not many manufacturers have this-because there are limited programs to use it in.

Programs such as EASE only model down to 100Hz-not exactly sub territory.

Other programs that have boundaries are only 2D.

The data for the boundaries in the 2D programs is also suspect.  They assume a perfect reflector-which all walls are not.  They flex at different freq so they can also act as absorbers to an extent. I am not sure how much data there is for walls and such below 100hz-since nobody has it in a modeling program.

Danley DDT models subs in 3D-but is limited to Danley subs.  But for now does not have reflective boundaries in the 3D version (2D has boundaries).

There may be some programs that will do this in the future.

But as with any modeling program-the model is only as accurate as the data that is put in-ie how well you build the model.

So for now (as far as I am aware of) you are up to a lot of "guesswork" and experience and possibly looking at plan and elevation view of 2D models to attempt to get an idea of what is happening.

In addition to what Ivan said, if you do some 2D modeling of subs with boundaries you will see how complex the interactions become. While they will be different for different rooms, there will only be gross changes that you can make to materially affect the coverage.

Outdoor prediction lets you play around with different sub arrays, indoors will be dominated by the reflections and will all be equally complex coverage grids of peaks and nulls.

Mac
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Ivan Beaver

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Re: 3D sub prediction software
« Reply #3 on: December 26, 2013, 12:09:32 pm »

In addition to what Ivan said, if you do some 2D modeling of subs with boundaries you will see how complex the interactions become. While they will be different for different rooms, there will only be gross changes that you can make to materially affect the coverage.

Outdoor prediction lets you play around with different sub arrays, indoors will be dominated by the reflections and will all be equally complex coverage grids of peaks and nulls.

Mac
Here are some quick models of a plan view that are 1 oct wide at 63Hz.  The upper one has the subs 15' on each side of center (30' apart).  The image on the left is with reflections and the one on the right is no reflections.

The lower image is with the subs 2' off center or 4' center to center.

You can see how the bass builds up along the walls and "fills in"-as compared to without reflections.
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Darren Scaresbrook

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Re: 3D sub prediction software
« Reply #4 on: December 26, 2013, 10:00:17 pm »

Thanks Mac and Ivan,

I have used GPA and other programs in the past and they do a good job of the basic modelling you are talking about.
I have a specific application I wanted to model in 3D. A directional array, outdoors, .5 pi loaded and using a close coupled (<.25wl) boundary to augment the pattern control.
While not truly 3D, any of the 2D programs should be able to give biplanar data by doing 2 simulations and substituting the y axis with a z axis for one of the simulations. As I said, this is not 3D, it is biplanar, but keeping this limitation in mind I may be able to get something useful.

Darren

ProSoundWeb Community

Re: 3D sub prediction software
« Reply #4 on: December 26, 2013, 10:00:17 pm »


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