Introducing the ATK: FOA examples | SuperCollider 3.13.0 Help

Getting started examples originally found in Introducing the Ambisonic Toolkit

Examples

The examples below are intended to briefly illustrate playback and imaging of soundfields with the ATK. The user is encouraged to explore the ATK's documentation to gain a deeper understanding of the flexibility of these tools.

As the Ambisonic technique is a hierarchal system, numerous options for playback are possible. These include two channel stereo, two channel binaural, pantophonic and full 3D periphonic. With the examples below, we'll take advantage of this by first choosing a suitable decoder with with to audition.

Choose a decoder

A number of decoders are defined below. Please choose one suitable for your system. Also, don't forget to define ~renderDecode !

NOTE: If you choose a kernel decoder, FoaDecoderKernel, be sure to free the kernel after use.

// ------------------------------------------------------------
// boot server
(
        s = Server.default;
        s.boot;
)

// ------------------------------------------------------------
// define convenience function to verify number of server outputs
(
~checkMyServerOutputs = { arg server, decoder;
    server.serverRunning.if({
        (decoder.numOutputs > server.options.numOutputBusChannels).if({
            "Number of Server output bus channels is less than number required by Decoder!".warn;
            "Server Outputs: %\n".postf(server.options.numOutputBusChannels);
            "Decoder Outputs: %\n\n".postf(decoder.numOutputs);
            "Update number of Server outputs as illustrated here: ".post;
            "http://doc.sccode.org/Classes/ServerOptions.html#examples".postln;
        }, {
            "Server has an adequate number of output bus channels for use with this Decoder!".postln;
        })
    })
}
)

// ------------------------------------------------------------
// choose a decoder

// stereophonic / binaural
~decoder = FoaDecoderMatrix.newStereo((131/2).degrad, 0.5) // Cardioids at 131 deg
~decoder = FoaDecoderKernel.newUHJ                         // UHJ (kernel)
~decoder = FoaDecoderKernel.newSpherical                   // synthetic binaural (kernel)
~decoder = FoaDecoderKernel.newCIPIC                       // KEMAR binaural (kernel)

// pantophonic (2D)
~decoder = FoaDecoderMatrix.newQuad(k: 'dual')             // psycho optimised quad
~decoder = FoaDecoderMatrix.newQuad(pi/6, 'dual')          // psycho optimised narrow quad
~decoder = FoaDecoderMatrix.new5_0                         // 5.0
~decoder = FoaDecoderMatrix.newPanto(6, k: 'dual')         // psycho optimised hex

// periphonic (3D)
~decoder = FoaDecoderMatrix.newPeri(k: 'dual')             // psycho optimised cube
~decoder = FoaDecoderMatrix.newDiametric(                  // psycho optimised bi-rectangle
    [[30, 0], [-30, 0], [90, 35.3], [-90, 35.3]].degrad,
    'dual'
)

// inspect
~decoder.kind
~checkMyServerOutputs.value(s, ~decoder)

// ------------------------------------------------------------
// define ~renderDecode
(
~renderDecode = { arg in, decoder;
    var kind;
    var fl, bl, br, fr;
    var fc, lo;
    var sl, sr;
    var flu, blu, bru, fru;
    var fld, bld, brd, frd;
    var slu, sru, sld, srd;

kind = decoder.kind;

case
        { decoder.numChannels == 2 }
            {
                // decode to stereo (or binaural)
                FoaDecode.ar(in, decoder)
            }
        { kind == 'quad' }
            {
                // decode (to quad)
                #fl, bl, br, fr = FoaDecode.ar(in, decoder);

// reorder output to match speaker arrangement
                [fl, fr, bl, br]
            }
        { kind == '5.0' }
            {
                // decode (to 5.0)
                #fc, fl, bl, br, fr = FoaDecode.ar(in, decoder);
                lo = Silent.ar;

// reorder output to match speaker arrangement
                [fl, fr, fc, lo, bl, br]
            }
        { kind == 'panto' }
            {
                // decode (to hex)
                #fl, sl, bl, br, sr, fr = FoaDecode.ar(in, decoder);

// reorder output to match speaker arrangement
                [fl, fr, sl, sr, bl, br]
            }
        { kind == 'peri' }
            {
                // decode (to cube)
                #flu, blu, bru, fru, fld, bld, brd, frd = FoaDecode.ar(in, decoder);

// reorder output to match speaker arrangement
                [flu, fru, blu, bru, fld, frd, bld, brd]
            }
        { kind == 'diametric' }
            {
                // decode (to bi-rectangle)
                #fl, fr, slu, sru, br, bl, srd, sld = FoaDecode.ar(in, decoder);

// reorder output to match speaker arrangement
                [fl, fr, bl, br, slu, sru, sld, srd]
            };
}
)

// ------------------------------------------------------------
// now we're ready to try the examples below!
// ------------------------------------------------------------

Produced via the Ambisonic Toolkit

The following three sound examples are excerpts from recordings produced via the ATK.

If you haven't already choosen a ~decoder and defined ~renderDecode, do so now.// ------------------------------------------------------------ // B-format examples, produced via the ATK // B-format soundfile read from disk // read a whole sound into memory // remember to free the buffer later! // (boot the server, if you haven't!) ~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Anderson-Pacific_Slope.wav") ~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Howle-Calling_Tunes.wav") ~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Pampin-On_Space.wav") ( { var sig; // audio signal // display encoder and decoder "Ambisonic decoding via % decoder".format(~decoder.kind).postln; // ------------------------------------------------------------ // test sig sig = PlayBuf.ar(~sndbuf.numChannels, ~sndbuf, BufRateScale.kr(~sndbuf), doneAction:2); // soundfile // ------------------------------------------------------------ // decode (via ~renderDecode) ~renderDecode.value(sig, ~decoder) }.scope; ) // free buffer ~sndbuf.free // ------------------------------------------------------------

NOTE: Soundfile Credits

Joseph Anderson, "Pacific Slope," Epiphanie Sequence, Sargasso SCD28056
Tim Howle, "Calling Tunes," 20 Odd Years, FMR FMRCD316-0711
Juan Pampin, "On Space," Les Percussions de Strasbourg 50th Anniversary Edition, Classics Jazz France 480 6512

Natural soundfields, with imaging transforms

This example illustrates the application of various spatial filtering transforms to natural soundfields, recorded via the Soundfield microphone.

The soundfield is controlled by MouseY, which specifies the transform angle argument (90 deg to 0 deg; top to bottom of display). With the mouse at the bottom of the display, the recorded soundfield is unchanged. At the top, the transform is at its most extreme.

If you haven't already choosen a ~decoder and defined ~renderDecode, do so now.

NOTE: See FoaTransform for further details.

// ------------------------------------------------------------
// B-format examples, natural soundfield with imaging transform
// B-format soundfile read from disk

// choose transformer
~transformer = 'zoomX'
~transformer = 'pushX'
~transformer = 'directO'

// read a whole sound into memory
// remember to free the buffer later!
// (boot the server, if you haven't!)
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Hodges-Purcell.wav")
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Leonard-Orfeo_Trio.wav")
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Courville-Dialogue.wav")
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Leonard-Chinook.wav")
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Leonard-Fireworks.wav")
~sndbuf = Buffer.read(s, Atk.userSoundsDir ++ "/b-format/Anderson-Nearfield.wav")

(
{
    var sig;                            // audio signal
    var angle;                          // angle control

// display transformer & decoder
    "Ambisonic transforming via % transformer".format(~transformer).postln;
    "Ambisonic decoding via % decoder".format(~decoder.kind).postln;

// gain ---> top            = 90 deg
    //           bottom         = 0 deg
    angle = MouseY.kr(pi/2, 0);

// ------------------------------------------------------------
    // test sig
    sig = PlayBuf.ar(~sndbuf.numChannels, ~sndbuf, BufRateScale.kr(~sndbuf), doneAction:2);   // soundfile

// ------------------------------------------------------------
    // transform
    sig = FoaTransform.ar(sig, ~transformer, angle);

// ------------------------------------------------------------
    // decode (via ~renderDecode)
    ~renderDecode.value(sig, ~decoder)

}.scope;
)

// free buffer
~sndbuf.free
// ------------------------------------------------------------

NOTE: Soundfile Credits

P. Hodges, "Purcell - Passacaglia (King Arthur)," Sound of Space: ambisonic surround sound. [Online]. Available: http://soundofspace.com/ambisonic_files/52 [Accessed: 03-Nov-2011].
J. Leonard, "The Orfeo Trio & TetraMic," Sound of Space: ambisonic surround sound. [Online]. Available: http://soundofspace.com/ambisonic_files/41 [Accessed: 03-Nov-2011].
D. Courville, "Comparative Surround Recording," Ambisonic Studio | Comparative Surround Recording, 2007. [Online]. Available: http://www.radio.uqam.ca/ambisonic/comparative_recording.html [Accessed: 26-Jul-2011].
J. Leonard, ""A couple of Chinook helicopters," Sound of Space: ambisonic surround sound, 20-Mar-2008. [Online]. Available: http://soundofspace.com/ambisonic_files/47. [Accessed: 03-Nov-2011].
J. Leonard, “Fireworks,” Sound of Space: ambisonic surround sound, 25-Aug-2009. [Online]. Available: http://soundofspace.com/ambisonic_files/37. [Accessed: 03-Nov-2011].
Joseph Anderson, "Near-field source," [unpublished recording]

helpfile source: HelpSource/Guides/Intro-FOA-Examples.schelp
link::atk-sc3/Guides/Intro-FOA-Examples::

Introducing the ATK: FOA examplesExtension

Examples

Choose a decoder

Produced via the Ambisonic Toolkit

Natural soundfields, with imaging transforms

Introducing the ATK: FOA examples
Extension