I am really trying to figure out how to use the 3d audio features of houdini, which I think are a potentially great idea.

I am trying to figure out how you apply the acoustic chop to geometry. I would like to be able to position a microphone in space and move the mic behind a wall with the audio source on the other side of the wall and have the wall filter out specific frequencies say the hi frequencies so that only the bass end gets through the wall to the microphone.

I am not sure if this is even possible, maybe I am misunderstanding the function of the node. I can't even out how to apply it to geometry.

I also can't figure out how to get audio to bounce off of geometry, which seems to be a feature of the acoustic audio chop. Any suggestions would be greatly appreciated.

I have purchased andrew lowells book and it is useful but have not be able to find clear documentation of these feature.


Thanks in advance for any advice or suggestions

You will need this

http://www.andrew-lowell-productions.com/andrew-lowell-productions/resources.html [andrew-lowell-productions.com]

R

For some reason, the sound material was moved into the Obsolete 8.0 geometry parameters, even though it is live & well. In the geometry you wish to add an acoustic CHOP to:

1) click on the gear icon in the parameter dialog header
2) select ‘Edit Rendering Parameters’
3) expand Obsolete Houdini 8.0, then Shading
4) add a Sound CHOP (chop_soundpath)
5) Accept
6) enter the path to the Acoustic CHOP in the new parameter (it appears in the Render/Shading tab of the Geo object)

Then it's just a matter of adjusting the curves in the Acoustic CHOP to pass (1) or filter out (0) the desired frequencies (they are /1000 on the X axis). ‘transmit’ is the filter applied to sound going through the object, while ‘reflect’ is the filter applied to sound bouncing off the object. ‘absorb’ is there as an extra handle to help adjust the first two; it isn't applied as a filter to anything.

Twod, thanks for the reply, that helps alot, I would have never found it. But after trying to work it for a while, I must still be doing something wrong, as I can't hear any difference yet.

I have set my acoustic node to only transmit sound, and the frequency range is set to 0-400. In the motion view I have set the transmit graph points to 1. I have loaded and reload my spatial audio into the audio panel chop in an effort to reset it and still no luck. I should only be hearing the bass end of my sound but instead I hear the full range of frequencies.

I am wondering if I need to set the spatial audio node to detect obstacles or does anything need to be selected in the filter chop in the microphone node.

Also I am not sure what you mean by

(they are /1000 on the X axis)

what gets divided by 1000 on the x axis and the x axis of what.

do you mean that the frequency range is divided by 1000.

Again any help is really appreciated,

yeah please put the sound material out of the obsolete !!!

Here's an odforce thread where I hacked into these features.

http://forums.odforce.net/index.php?showtopic=6244&hl=acoustic [forums.odforce.net]

Spatial recording is covered in depth in the book but I didn't get into the sound absorption stuff since the chapters were so large anyway and it isn't as valuable as good stereo placement. It's working in that hip file on the thread though, works great.

The trick is to get the softness very low so the occlusion object actually absorbs sound, a value of 1 will absorb very little which might make you think it's broken (but it is working fine).

It certainly shouldn't be obsolete though there's tons of applications for it .. there was just too much to cover

:twisted:

Thanks Andrew for the files, they were a big help. But now I seem to be having trouble with the acoustic node. whenever I use it in a project. When I try to reload that project. I get the error message Missing token: { acoustic1.acous“. and if I try to enable audio in the audio panel the project crashes.

I even get the error message if I just create an empty project with just and acoustic node inside of a chopnet.

I am wondering if this is a bug of 9.5.241 apprentice. or a mac bug. I seem to be getting a lot of crashes. Does the audio side of houdini runs smoothly for you.

I can open the file you posted ”sound_and_occlu_H9" just fine put if I save it in 9.5 and try to reopen again same error message.

Now that I am writing this I see that version 9.5.3 is out I will download and give it a try.

same problem with 9.5.3

could you post the file that consistently crashes?

Here is a file typical of the problems I am having.
It give that same load error and on this one if I try to display the transmit and absorb handles on the motion view pane. The file crashes.

In the next major release of Houdini, the chop_soundpath will be moved out of Obsolete H8 parms.

Jenny.

yipieeee!!

does this mean that all of the reflection and absorption features will be working. I am really interested in experimenting with setting up virtual spaces and see how sound bounces and is absorbed by different surfaces

hmmm, they should be working .. sorry I wasn't able to check out that file but I'll try to sometime this week