http://ambisonictoolkit.net/
http://supercollider.sourceforge.net/
- Brief introduction to Ambisonics
- Introducing the Ambisonic Toolkit
- Examples (Authoring, Imaging, Monitoring)
Ambisonics is a series of recording and playback techniques invented by Michael Gerzon (among others) in the early 1970s. Some of its features includes:
- Full 3D surround (with only 4 channels - First order B-Format)
- Hierarchical - from mono to 3D surround and binaural
- Arbitrary speaker setups. The ambisonic signal (B-Format) carries its directional information independently from any loudspeaker setup. This means that you can easily decode the B-Format signal into another loudspeaker configuration, without having to worry about altering your final mixdown.
To view more of advantages of working with ambisonics, visit for instance Wikipedia
To learn more about ambisonics in general, check out these links:
Wikipedia
http://en.wikipedia.org/wiki/Ambisonics
Ambisonic.net
http://www.ambisonic.net/
D.G. Malham, Spatial hearing mechanisms and Sound reproduction
http://www.york.ac.uk/inst/mustech/3d_audio/ambis2.htm
F. Hollerweger, An Introduction to Higher Order Ambisonic
http://flo.mur.at/writings/HOA-intro.pdf/view
A first order B-Format signal contains four channels of information, which are called: [ W, X, Y, Z ]. Each of these channels can be thought of as having a corresponding microphone polar pattern. If one uses this analogy this would mean that:
- W – 'pressure' the output from an omnidirectional microphone.
- X – 'front/back' the output from a figure-of-eight microphone.
- Y – 'left/right' the output from a figure-of-eight microphone.
- Z – 'up/down' the output from a figure-of-eight microphone.
The Ambisonic Toolkit (ATK) is a SuperCollider library which provides a set of different tools and transforms for working with ambisonic surround sound.
ATK has a production model, or paradigm, which is breaks down the task of working with Ambisonics into three separate elements:
- Author - Capture or synthesise an Ambisonic soundfield.
- Image - Spatially filter an Ambisonic soundfield.
- Monitor - Playback or render an Ambisonic soundfield.