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IKO history

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THE IEM ICOSAHEDRAL LOUDSPEAKER (IKO) consists of an icosahedral housing carrying 20 individually driven loudspeakers. IKO has been built in 2006 by Franz Zotter at IEM Graz, originally with the idea to holographically mimic musical instruments.

Gerriet K. Sharma and Franz Zotter started working on turning the IKO into an instrument and composition tool from 2009-2012 targeting a new manifestation of spatial sound in contemporary computer music. As a result of this fruitful composer acoustician dialogue, the compositions grrawe (10’26’’) and firniss (11’23’’) could be developed. These two pieces were stepping stones to thinking about the technical device and its acoustical principles as a means of artistic expression and orchestration of sounds in space.

From 2014-2018 “Orchestrating Space by Icosahedral Loudspeaker” (OSIL) became a research project funded by the Austrian Research Fund within the framework of the Programme for Arts-based Research (FWF/PEEK) at the Institute of Electronic Music an Acoustics Graz (IEM). Members of the research team were: Franz Zotter, Gerriet K. Sharma, Matthias Frank, Florian Wendt, and Markus Zaunschirm supported by Frank Schultz and supervised by Robert Höldrich.
IKO was tested and performed in over 40 international concerts and subject to over 30 scientific and artistic research publications.

In 2016 the Graz based start-up sonible developed a new amplification and loudspeaker system taking the IEM concept to a state of the art production, performance, and marketing level.

THE IEM-sonible ICOSAHEDRAL LOUDSPEAKER (IKO) is now a new musical instrument with unique and characteristic features in the field of spatialisation and sound sculpting

sonible and the new IKO

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COMMON SPATIALIZATION SYSTEMS for computer music employ loudspeaker arrays that surround the listening area, such as the BEAST (University of Birmingham), the Espro (IRCAM), the Klangdom (ZKM), the CUBE and the MUMUTH (KUG). They either use the psychoacoustic phenomenon of a phantom source to create auditory objects between the loudspeakers, e.g. VBAP and Ambisonics, or aim at recreating a physically accurate sound field, e.g. wave field synthesis.

THE NOVELTY IN IKO in contrast to common surrounding loudspeaker systems lies in controlling the strengths of the wall reflections that could be excited from a single performer’s location. Namely an icosahedral loudspeaker is employed as an instrument of adjustable directivity at this location.

In electroacoustic music, the notion of adjustable-directivity loudspeakers was introduced in Paris in the late 1980s by researchers at IRCAM. For the renowned concept study “la timée”, a cube housing six separately controlled loudspeakers was built to achieve freely controllable directivity. Despite the ingenious idea and theory, loudness and focusing strength weren’t convincing enough to be employed in concerts. In 2006, researchers at IEM (University of Music and Performing Arts Graz) reconsidered theory aiming at an acoustically correct and powerful reproduction of musical instruments in their lower registers, including the entire 3D directivity pattern. The resulting icosahedral loudspeaker (IKO) is more powerful, of larger size, and larger number of loudspeakers. Moreover, a success in quality was achieved by reconsidering algorithms and acoustic calibration to control sound beams that are three times narrower than beams of earlier systems.

THE IKO TRULY PERMITS TO FORM THREE-DIMENSIONAL AUDITORY OBJECTS. Its strongly focused sound beams can be projected onto floors, ceilings and walls. The direct sound from the IKO is often attenuated so that instead, sounds from acoustic room reflections become audible. Beams are freely adjustable in terms of direction. As alternative ways to spatialize, different beams can be blended, or their beam width manipulated. Sculptural auditory objects created by the IKO can be moved around towards the reflecting surfaces or collapse onto the IKO. What is more, objects can be composed as to include useful gradation of depth, which was recognized in research with audience/listener-responses.