Software Tools for Flexible Control of Radiation Synthesis

Compact spherical loudspeaker arrays are new tools for the creation of auditory objects in a space. Originally designed for musical and performance purposes – as a substitute for conventional cabinet loudspeakers lacking naturalness in playback – they intent to promote spatial presence and to emulate lifelike directional features of natural sources such as acoustic instruments and performers. They are typically used to reproduce the measured radiation pattern of sound sources, or to steer directional sound beams in order to excite the acoustic environment. The directivity pattern of the sound beams can be adjusted, in orientation and shape, by modal beamforming techniques.In electroacoustic music, it is most often desirable to apply dynamic beamforming, i.e. to vary the directional attributes over time, in order to effectively enable a sense of spatial presence or immersion. This paper presents a software tool, intended for creative applications, for the flexible design and intuitive manipulation of spherical beampatterns. In particular, we propose a simple parametric model that allows to synthesize a variety of high-order radiation patterns, and to smoothly transition between shapes. The tool is implemented in the Max environment, making it easy to extend and to interface with remote controllers for interactive applications.