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.

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. 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.

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. 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.

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