Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Don W. <don...@ya...>]

You might want to take a look at Ambisonics as a good starting point:

    http://en.wikipedia.org/wiki/Ambisonics

The Furse-Malham set extend this to 2nd and 3rd order SH:

    http://www.muse.demon.co.uk/3daudio.html

This kind of tech was effectively used in DiRT by Codemasters:

    
http://blog.ambisonia.com/2007/08/30/interview-with-simon-goodwin-of-codemasters-on-the-ps3-game-dirt-and-ambisonics/


And of course, you can rotate them... ;)

Cheers,
- Don

    





________________________________
From: Oscar Forth <os...@tr...>
To: Game Development Algorithms <gda...@li...>
Sent: Sat, July 17, 2010 9:22:26 PM
Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling

Sweet!  I'll take a look, ta :)

You wouldn't happen to have any links that would save me a bit of time and 
google trawling?  No worries if not :)


On 17 July 2010 21:03, Deano <de...@ra...> wrote:

Search for wave tracing in the literature. For acoustics, wave behavior is vital 
unlike most lighting equations, as such you need to model waves transfer and 
also for most audio surfaces unlike visual surfaces they are not 100% reflective 
and so subsurface scattering is way more important.
> 
>There is some interesting work out there, including at least one GPGPU real-time 
>system.
> 
>Deano
> 
>From:Oscar Forth [mailto:os...@tr...] 
>Sent: 17 July 2010 20:10
>To: Game Development Algorithms
>Subject: [Algorithms] Spherical harmonics for room acoustic modelling
> 
>I will admit first off I don't have a great knowledge of things like 
>Pre-computed Radiance Transfer but I was having a chat with a colleague recently 
>on how audio research lags behind video research in gaming.
> 
>One idea that we were talking about is using spherical harmonics in a similar 
>way to PRT to do some sort of Pre-computed Acoustic Transfer.
> 
>Basically you'd add a new material type to a room that would give you the sound 
>reflectivity of a given surface.   You could then use the same techniques 
>(obviously calculated with something like OpenCL) to give you a good model of 
>how sound moves round a room.  Has anyone done anything like this?
> 
>It kinda struck me that you'd be able to model things like acoustic reflections 
>off a hard surface, acoustic dispersion from soft surfaces as well as getting 
>things like occluders thrown in as a bonus.  Add to that you could use the same 
>techniques as are used for translucent surfaces to model sound transfer through 
>a surface and the slight bending of audio round corners.
> 
>Are there any papers on the subject at all?  It struck me as something worth 
>finding more out about as it would give the ability to create truly rich sound 
>scapes with very little actual fiddling needed to get it right.  You'd just pass 
>the model through your PAT calculation engine then play sounds and get them 
>playing right.
> 
>Any thoughts?
> 
>Cheers!
> 
>Oscar
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