Directivity Extension

Version 35 (Nils Peters, 06/02/2009 04:21 pm)

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h1. Directivity Extension
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    * Orientation of entity (Yaw, Pitch, Roll)
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    * Directivity model ...... there are different models out there, what might be the best?
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          o AudioTwist
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          o Spatialisateur (aperture)
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          o Space Unit Generator
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          o openAL, directX 
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          o X3D (ellipsoids)
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          o CATT-Acoustics (SD0, SD1, SD2 file format)
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          o Common Loudspeaker File Format (CLF)
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h1. Review
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h2. [[Spatialisateur]] 
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h2. [[Space Unit Generator]]
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!SUG.gif!
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h2. ViMiC
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The source directivity can be modeled through a frequency independent gain factor between 0 and 1. for each radiation angle to a 1ยบ accuracy.     
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!ViMiC.gif!
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h2. AudioTwist
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h2. "OpenAL":http://connect.creativelabs.com/openal/default.aspx
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??ability to simulate realistic directivity characteristics by either *specifying parametric filtering associated to radiation angles*, or *triplets of angle, frequency and attenuation*.?? 
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       (Jean Marc Jot, "Scene Description Model and Rendering Engine for Interactive Virtual Acoustics", 120th AES Convention)
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h2. "X3D":http://libx3d.sourceforge.net/ISO-IEC-19775-X3DAbstractSpecification/index.html  Sound Node
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    * Inner ellipsoid defines a volume of space in which the maximum level of the sound is audible. Within this ellipsoid, the normalized sample data is scaled by the intensity field and there is no attenuation. The inner ellipsoid is defined by extending the direction vector through the location. The @minBack@ and @minFront@ fields specify distances behind and in front of the location along the direction vector respectively. The inner ellipsoid has one of its foci at location (the second focus is implicit) and intersects the direction vector at @minBack@ and @minFront@.
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* Outer ellipsoid defines a volume of space that bounds the audibility of the sound. No sound can be heard outside of this outer ellipsoid. The outer ellipsoid is defined by extending the direction vector through the location. The @maxBack@ and @maxFront@ fields specify distances