Author: Marlon Schumacher
Funding:
NSERC/ CCA (Spatialization)
CIRMMT Inter-Centre Exchange Grant
CIRMMT/GREAT travel awards
Status:
ongoing
OMPrisma is a library for spatial sound synthesis in the computer-aided composition environment OpenMusic. In addition to the control of spatialization-processes using pre-existing sound sources it permits the synthesis of sounds with complex spatial morphologies via processes developed in OpenMusic in relation to other sound synthesis parameters and to the symbolic data of a compositional framework.
The OMPrisma system-architecture separates authoring and description of spatial sound scenes from rendering and reproduction (see the ISASA2010 paper). This approach allows a user to render alternative realizations of the same spatial sound scene using different rendering techniques and loudspeaker arrangements.
While OMPrisma 1.0 focused on compositional control of sweetspot-based spatialization techniques (such as VBAP or Ambisonics), OMPrisma 2.0 introduces new classes for spatialization techniques for non-centralized audiences (such as dbap, babo or ViMiC), allowing for arbitrary loudspeaker arrangements, e.g. on stage, between the audience, for installations, etc. The screenshot below shows a patch in which an OMPrisma class for Virtual Microphone Control (ViMiC) is used to simulate the spatialization technique employed in K.H.Stockhausen's “Kontakte” (1959/1960), using a rotational table with a mounted directional speaker (sound source) and four stationary microphones placed around it*.

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* A detailed description of this technique can be found in: Braasch, J., Peters, N., and Valente, D. L. (2008). A loudspeaker-based projection technique for spatial music applications using Virtual Microphone Control. Computer Music Journal, 32(3):55 – 71.
OMPrisma has been used for the composition and realization of a number of works, most notably: