Birmingham ElectroAcoustic Sound Theatre

Birmingham ElectroAcoustic Sound Theatre, or as it is more commonly known, BEAST, is a sound diffusion system specifically designed for the performance of electroacoustic music. Created in 1982, it is a long-running project of the Electroacoustic Music Studios at the University of Birmingham under the directorship of Jonty Harrison. Simply put, it consists of a set of loudspeakers connected to a diffusion console.

The loudspeakers

BEAST can consist of up to over 100 channels of loudspeakers arranged in pairs, or more recently to allow the diffusion of octaphonic works, circles of eight, and includes ultra-low frequency loudspeakers ("bins") and custom-built trees of high frequency speakers ("tweeter trees") which can be suspended above an audience.

The minimum set-up that BEAST would ordinarily use for stereo diffusion comprises a set of loudspeakers which Jonty Harrison terms the "Main Eight"cite web
last = Harrison
first = Jonty
authorlink = Jonty Harrison
title = Diffusion: theories and practices
publisher = CEC Journal: eContact!
date = 1999
url =http://cec.concordia.ca/econtact/Diffusion/Beast.htm
accessdate = 2007-04-26] cite journal
last = Harrison
first = Jonty
authorlink = Jonty Harrison
title = Sound, space, sculpture: some thoughts on the 'what', 'how' and 'why' of sound diffusion
journal = Organised Sound
volume = 3
issue = 2
pages = 117–27
publisher = Cambridge University Press
date = 1998
doi = 10.1017/S1355771898002040 ] . These four pairs of loudspeakers, using BEAST nomenclature, are termed "Main", "Wide", "Distant" and "Rear". The "Main" and the "Wide" speakers together form the main, frontal sound image, the "Main" speakers being placed to act somewhat like the loudspeakers in a typical studio, and the "Wide" speakers acting to stretch that sound image out across the audience's sound stage. The "Rear" speakers, which are behind the audience, provide immersion and the possibility of movement around the audience. Finally, the "Distant" speakers, which are positioned to hold their image behind the "Main" speakers, create a sound whose perspective is distant to that of the "Main" pair. Other speakers are added to this "Main Eight" to allow additional possibilities for sound movement and differing sound perspectives.

The diffusion console

BEAST is a dynamic system: during a performance the performer operates an often custom-built console, called the diffusion console, with which he or she can individually and dynamically control the level of each loudspeaker, or groups of loudspeakers. This enables him or her to actively articulate the piece's implied spatial sound detail within the real space of the performance venue, in order to realise and interpret the composer's intentions.Harvard reference
Surname=Harrison
Given=Jonty
authorlink = Jonty Harrison
Year=1988
Chapter=Space and the BEAST concert diffusion system
Editor=Francis Dhomont
Title=L'espace du son
Publisher=Musiques et Recherches
Place=Ohain ] The system also includes equipment for the live processing of sounds so that, for instance, the sounds of a live violinist can be processed and incorporated into the soundstage.

The BEAST diffusion console has developed significantly over the years. The earliest systems depended on those commercially available mixing desks which had direct outputs from each fader. The stereo input signal from, for example, a tape-machine was split passively into the input channels on the desk, alternating left and right. The direct output from each channel fed the amplifiers for the loudspeakers, thus giving the individual control of each loudspeaker required for diffusion. The main disadvantage of this system was that it offered very little flexibility, making it difficult to move between sources in different formats (for example, quadraphonic, octaphonic or pieces with live input). In some situations complicated rewiring would required for each source format used, which could be prone to errors particularly during the stress of a performance.cite journal
last = Austin
first = Larry
authorlink = Larry Austin
title = Sound Diffusion in Composition and Performance Practice II: An Interview with Ambrose Field
journal = Computer Music Journal
volume = 25
issue = 4
pages = 24
publisher = MIT Press
date = 2001 ]

The first custom built console BEAST developed was still based on a commercially available mixing desk, but which had been extensively modified, adding a matrix input section and balanced outputs. The matrix input section allowed a number of inputs to be assigned to any fader input using a series of push buttons. Where multiple sources were used during a concert, this allowed each work to have their assignment preset on the matrix. BEAST's positive and negative experiences with this experimental desk led them to design a new one: their last analogue desk, still in use, called the "3D". This was a fully custom built console with an extensive matrix input which was very easy and flexible to use.

With the electroacoustic community's renewed interest in multichannel formats, and in particular octaphonic set-ups, came the need for BEAST to address how such pieces should be diffused. The diffusion of multichannel formats was too complex a task for the standard BEAST console, even the 3D, and BEAST turned to software solutions to solve these problems: first MAX/MSP and most recently, a system created in SuperCollider by Scott Wilson and Sergio Luque. Now, rather than using an analogue desk, a digital multichannel sound interface is used, and controlled via specially written applications using MIDI faders. This offers the maximum flexibility, with one fader, for example, being able to control only one loudspeaker, a stereo pair or an octaphonic circle depending on how the system has been configured. Using this system, multiple octaphonic groups, placed in different positions around the audience, can be used to diffuse octaphonic source material in a manner similar to that used for stereo. In this case, each fader controls one octaphonic group.

Performances

Since its debut in December 1982, BEAST has performed in over 140 concerts in the UK and Europe, both on its own and in joint performances with musicians from all over the world. BEAST has appeared at many notable festivals and concerts, including the Edinburgh International Festival, Huddersfield Contemporary Music Festival, Multimediale 2 in Karlsruhe, in the Purcell Room and the Royal Festival Hall, The Royal Dutch Conservatory in Den Haag, the Adrian Boult Hall in Birmingham and the Henry Wood Hall in Glasgow. It was acclaimed when used as the concert sound system at the 1990 International Computer Music Conference held in Glasgow, and at the Aspekte Festival in Salzburg.

ee also

*Acousmonium
*Surround sound

References

* [http://www.ea-studios.bham.ac.uk/ The Electroacoustic Music Studios at the University of Birmingham.] Retrieved on 22 April 2007.
*cite journal
last = Tutschku
first = Hans
title = On the Interpretation of Multi-Channel Electroacoustic Works on Loudspeaker-Orchestras: Some thoughts on the GRM-Acousmonium and BEAST
journal = Journal of Electroacoustic Music
volume = 14
pages = 14–16
publisher = Sonic Arts Network, London
date = 2002
*cite web
last = Dack
first = John
title = Diffusion as Performance
publisher = Centre for Electronic Art, Middlesex University
date = 2001
url =http://www.sonic.mdx.ac.uk/research/dackdiffusion.html
accessdate = 2007-04-22