Conference PaperPDF Available

Authoring complex Ambisonic soundfields: An artist’s tips & tricks



When first working with Ambisonics, the artist is usually presented with encoding (panning) tools intended to spatialise single point sources. When complex soundfields are generated through this approach, the results may be regarded as created via a sound-scene based paradigm in some way modelling a real- world scene. In contrast, this paper presents a sound-kernel paradigm and techniques for the generation of complex soundfields. This approach instead focuses on the direct generation of complex soundfield kernels as a starting point. A number of spatial authoring approaches, ranging from time/spatial-domain to frequency/spatial-domain techniques, are presented, discussed and illustrated with sound examples—which include musical excerpts from the author’s catalogue. Strategies to ‘upgrade’ well known two-channel stereo effects to Ambisonics and soundfield kernel processing are also introduced. Additionally, spatial imagining transforms from the author’s Ambisonic ToolKit (ATK) are described and demonstrated, enabling the artist to control the generated complex soundfields. Keywords: ambisonics, surround sound, spatialisation, spatial filtering, digital audio effects
Sounds in SPACE Symposium
Friday, 17 June 2011
University of Derby
Derby, England
Joseph Anderson
independent artist
Authoring complex Ambisonic soundfields:
An artist’s tips & tricks
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 2/11
Epiphanie Sequence
Kyai Pranaja (1998)
Mpingo (2003)
Pacific Slope (2002)
Composed in full 3D (periphonic) B-format
Using B-format source recordings
Published by Sargasso Records
UHJ Stereo on CD
B-format versions available (on request!)
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 3/11
Ambisonic Encoding
OUTRS tetrahedral microphone array, courtesy Stephen Thornton
Soundfield microphone, courtesy Soundfield Ltd.
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 4/11
The Trick: A-format
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 5/11
The Trick: Ambisonic Toolkit (ATK)
Audio Effects
Process in A-format!
… in A-format!
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ATK Imaging: Zoom
Zoom Transform
Reshape Soundfield
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ATK Imaging: Focus
Focus Transform
Reshape Soundfield
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ATK Imaging: Push
Push Transform
Two metaphors:
Spatial Shelving-Filter
Re-align Tetrahedron
Reshape Soundfield
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Listening & Discussion
Ambisonic Toolkit
(SuperCollider Library)
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 10/11
[1] J. Anderson, Epiphanie Sequence, vol. 28056. London: Sargasso, 2008.
[2] J. Anderson, “Introducing... The Ambisonic Toolkit,” in Proceedings of the Ambisonics Symposium 2009, Graz, 2009.
[3] J. Anderson and J. Parmenter, “The Ambisonic Toolkit,” Ambisonic Toolkit (ATK), 2011. [Online]. Available:
[4] J. L. Anderson, “Portfolio of Compositions,” PhD Thesis, University of Birmingham, 2003.
[5] C. Dodge and T. A. Jerse, Computer Music: Synthesis, Composition, and Performance. New York: Schirmer Books, 1985.
[6] K. Farrar, “Soundfi eld microphone: design and development of microphone and control unit,” Wireless World, pp. 48-50 (Oct.), 99-
103 (Nov.), 1979.
[7] R. Furse, “Sound System: Methods and systems for using transforms to modify the spatial characteristics of audio data,” U.S.
Patent GB 2467534 A11-Aug-2010.
[8] M. A. Gerzon, “Periphony: With-Height Sound Reproduction,” Journal of the Audio Engineering Society, vol. 21, no. 1, pp. 2-10,
Feb. 1973.
[9] M. A. Gerzon, Artifi cial Reverberation and Spreader Devices. NRDC, 1975.
[10] M. A. Gerzon, Panpot and Soundfi eld Controlls. NRDC, 1975.
[11] M. A. Gerzon, “Ambisonics in Multichannel Broadcasting and Video,” Journal of the Audio Engineering Society, vol. 33, no. 11, pp.
859-871, Nov. 1985.
[12] D. G. Malham and A. Myatt, “3-D Sound Spatialization using Ambisonic Techniques,” Computer Music Journal, vol. 19, no. 4, pp.
58-70, 1995.
[13] D. Menzies, “W-panning and O-format, tools for object spatialization,” in Proceedings of the Audio Engineering Society 22nd
International Conference on Virtual, Synthetic and Entertainment Audio, Espoo, Finland, 2002.
[14] SoundField Ltd., “SoundField Technology and B-Format,” SoundField: SoundField Technology and B Format, 2001. [Online].
Available: http://soundfi eld/technology.php. [Accessed: 09-Jun-2011].
[15] S. Thornton, “Tetrahedral Recording Session Images,Michael Gerzon Audio Pioneer, 2009. [Online]. Available: [Accessed: 17-Apr-2011].
[16] “Tetrahedron,” Tetrahedron - Wikipedia, the free encyclopedia, 11-May-2011. [Online]. Available: [Accessed: 09-Jun-2011].
[17] “SuperCollider: real-time audio synthesis and algorithmic composition,” SuperCollider » About. [Online]. Available: [Accessed: 15-Dec-2010].
Joseph Anderson — 17 June 2011 Sounds in SPACE:Authoring Soundfields 11/11
... The encoded 2nd order ambisonic signal is converted to a 12-channel A-format signal and convolved with a B-format RIR which has been upsampled to 2nd order and converted to A-format impulse spectrum, a process that is performed automatically on first initialisation. A final step converts this reverberated A-format signal back to 2nd order B-format for decoding and audition (Anderson, 2011). ...
Conference Paper
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Mosca is a software extension class of the SuperCollider language for sound synthesis and algorithmic composition. It produces three-dimensional sound fields via an intuitive graphical user interface controlling a variety of hidden internal methods. Drawing from ambisonics' adaptable form of surround sound applicable to wide-ranging loudspeaker configurations and headphones, Mosca is suitable in a variety of applications. Recent improvements to the software include the incorporation of high-order ambisonics and the OSSIA/score project, enabling sophisticated control of audio spatialisation and synchronisation with a variety of media. Additionally, current development will bring location sensitivity to Mosca. Together with existing head-tracking capacities for binaural audio reproduction, the software will be highly useful in mixed and virtual reality projects. Mosca est une extension pour l'environnement de programmation audio SuperCollider. Cette extension permet la production de champs sonores tridimensionnels à travers une interface graphique intuitive et différentes méthodes internes. Tirant profit de la flexibilité du format ambisonique, compatible avec le rendu au casque et une large gamme de configurations d'enceintes, Mosca peut s'adapter à un grand nombre d'applications. Ce programme est actuellement développé par les auteurs pour intégrer des ordres ambisoniques supérieurs, et davantage de techniques de spatialisation, ainsi que le projet OSSIA/score, permettant un contrôle sophistiqué et la synchronisation, avec différents médias. En outre, les développements actuels apporteront à Mosca une localisation GPS de l'auditeur. Avec les possibilités actuelles de suivi du mouvement de la tête pour le rendu binaural, le programme pourra facilement être utilisé pour des projets de réalité virtuelle et mixte.
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This article describes artistically and technically, “Botanica”, a sound art work for gardens by the author. In the work, participants, together with a guide, use headphones and a laptop-equipped shoulder bag to explore an immersive sound composition overlaid on the landscape. The sounds heard are, for the large part, derived from nature and involve audio recordings from the cerrado environments of Brazil’s central west. As participants walk through the garden, their movements are tracked by GPS and this allows them to hear a variety of sounds mapped to different locations. The overlapping soundscapes encountered are 3-dimensional and head-tracking on the headphones helps to deliver a interactive immersion responsive to the finest movements of the listener. Sounds may be fixed in space, acting like beacons, or may follow their own trajectory through the garden. The headphones are of an open type, allowing the natural sounds of the environment to blend with those of the overlay. Botanica is presented as a sonic fantasy. It is inspired by landscape, the biosphere and the elements and is returned to the environment in a form to be explored in a specific setting, the garden, another fantasy of and for nature. It is a sound composition organised in space rather than time and as such interacts directly with the environment and with human presence. Botanica is an outcome of his research in the field of ambisonics (a form a surround sound) and specifically the project “Ambisonic Cerrado” which involves the use of ambisonic field recordings of the cerrado in theatrical contexts. The author’s open source computer software “Mosca” (an ambisonic extension class to the “SuperCollider” music language) was created in the research and forms the technical basis of Botanica.
Conference Paper
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The Ambisonic Toolkit (ATK) brings together a number of tools and transforms for the artist working with Ambisonic surround sound. The toolset in intended to be both ergonomic and comprehensive, providing algorithms to creatively manipulate and synthesise Ambisonic soundfields. The tools are framed so that the user is encouraged to ‘think Ambisonically’. By this, it is meant the ATK is not focused on the problem of auralisation or room modelling. Instead, by addressing the holistic problem of creatively controlling a complete soundfield, the ATK allows and encourages the artist to think beyond the placement of sounds in a sound-space and instead attend to the impression and image of a soundfield, therefore taking advantage of the native model the Ambisonic technique presents. A number of novel imaging transforms not seen in the literature are described.
Conference Paper
Full-text available
This demonstration provides a hands on introduction to the powerful soundfield authoring, transformation and playback techniques made available to the SuperCollider3 user through the Ambisonic Toolkit (ATK). The ATK brings together a number of classic and novel tools for the artist working with Ambisonic surround sound and makes these available to the SuperCollider3 user. The toolset is intended to be both ergonomic and comprehensive, and is framed so that the user is enabled to ‘think Ambisonic’. By this, the ATK addresses the holistic problem of creatively controlling a complete soundfield, facilitating spatial composition beyond simple placement of sounds in a sound-scene. The artist is empowered to address the impression and imaging of a soundfield—taking advantage of the native soundfield-kernel paradigm the Ambisonic technique presents. Along with powerful soundfield transforms (spatial filtering), the ATK provides a comprehensive set of Ambisonic encoders (including pseudo-inverse encoders) and decoders (5.1, binaural, UHJ, full-3D) allowing the artist to thoroughly leverage the potential of the Ambisonic technique. Keywords: ambisonics, surround sound, spatialisation, spatial filtering, digital audio effects Links:
Full-text available
INTRODUCTION The primary problem in spatialization is creating and controlling the perception of sound from different directions, since then in principle any soundfield can be simulated by mixing appropriate sounds in different directions. [1, 2, 3, 8, 10] are all focused on this objective. By contrast, little has been written about the secondary problem of simulating composite structures that generate a variety of sound from different directions over an extended space. The need for doing this arises very naturally from the sound produced by composite real objects, whether solid or fluid in nature. For instance, a passing vehicle emits a variety of different sounds from different parts, projected in various directions. A swarm of bees flying past the listener even creates a soundfield that completely envelopes the listener. One approach to modelling such complex audio scenes is to break it into a set of independent point sources. The game audio technology provider Sensaura [13] does t
The investigation on the application of ambisonics to the composition and performance of electroacoustic music is reported. Csound implementations of ambisonic encoding and decoding techniques that can be used in any computing platform supporting four or more independent audio output channels are also presented. Moreover, a variety of spatialization techniques is examined within a historical and technical context. This provides the basis for a review of ambisonic theory.
The FCC's effective deregulation of FM multichannel broadcasting standards, and the advent of multichannel audio via satellite, cable, and video systems, pose the question of the most effective use of 3 or 4 related audio channels. The Ambisonic UHJ hierarchy for transmitting total sound fields offers more varied mutually compatible applications than do other proposals (such as quadraphonics), with options up to and including full-sphere ('periphonic') directional reproduction. These options are detailed, including mono, stereo, 2-, 2 1/2, 3-, and 4-channel horizontal surround encoding, 4-channel periphony, and a range of user sound field adjustments in stereo and psychoacoustically optimized surround-sound reproduction modes.
Periphony (sound reproduction in both vertical and horizontal directions around a listener) may be recorded among others, via practical two-, four-, and nine-channel systems. matrix parameters and microphone techniques are described for 19 different systems, and a design procedure for other periphonic systems is given. Amplitude and energy directional resolution are discussed, as is compatibility with current horizontal-only systems.
Portfolio of Compositions
  • J L Anderson
J. L. Anderson, "Portfolio of Compositions," PhD Thesis, University of Birmingham, 2003.
Soundf i eld microphone: design and development of microphone and control unit Wireless World
  • K Farrar
K. Farrar, " Soundf i eld microphone: design and development of microphone and control unit, " Wireless World, pp. 48-50 (Oct.), 99-103 (Nov.), 1979.