A Spatial Composition

for two pioneering instruments

Helder Tenor Recorder & Icosahedral Loudspeaker


by Susanne Fröhlich (*) and Gerriet K. Sharma (*)


Semaphor was developed for Helder Tenor and Icosahedral Loudspeaker (IKO) in a cooperation between sound artist and composer Gerriet K. Sharma and the musician Susanne Fröhlich. The piece attempts to discover the shared perceptual spectrum of both instruments in dialogue and thus to expand the aesthetic possibilities to spatial composition in the present. The time frame of two years, the step-by-step growth of the piece as well as the unique setting of two prototypes joining a dialogue, exploring the aesthetic possibilities of spatial composition, are what makes this work special and forms its strength.


This collaboration was characterized by the fact, that I was allowed to fail.
Susanne Fröhlich





At the center of all artistically researching efforts is the question of "Shared Perceptual Space" (SPS). It is the space in medially mediated music where the perceptions of composers, musicians and the audience overlap with regard to the three-dimensional sound objects.

The research work attempts to limit this space through artistic actions or to provoke its emergence in the confrontation with other disciplines. It also aims to find a poetic approach to contemporary sound art as music in order to artistically incorporate complex sound-space environments. It is an invitation to the listener to participate in an expanded ontology of auditory space arts in the present.

Understanding both instruments as sound projectors, sound textures in sculpturally entangled states, spatially demarcated sound layers and scenographies can be composed and perceived in a way, scarcely producible in this ensemble constellation until now.

The Ikosahedral Loudspeaker (IKO) is a compact playback device that uses acoustic algorithms to project sound beams into freely adjustable directions, using wall reflections leading to the listener.

These „beams“ are not only freely adjustable in terms of their radiation angle, also different ones can be blended, or their beam width can be increases. In this way, the sound sources on the reflecting surfaces can be moved around, or collapse into the IKO.

On doing so, three-dimensional sound objects „appear“ that are hardly describable with common terminology

The bore of the Helder Tenor Recorder is based on the principle of pure harmonics for a balanced range of three octaves. It has extra keys for a strong sounding low register and an overall good intonation as well as a piano key for dynamic playing and stabilizing the third octave.

The block system is flexible for varied sound colours and adjustments regarding humidity and temperature.

The next step was to discuss various performance modi of the IKO, which Gerriet K. Sharma has developed during his artistic research project and which could be now used in the combination with Susanne Fröhlich as a live performer. These performance modi were very helpful for Fröhlich’s improvisations with the IKO and include the follwing:


to raise or lower
to fill
to masque
to add
to imitate

The two artists structured Semaphor in ten distinctive sections and in each of them Susanne Fröhlich was exploring special features of the Helder Tenor, respectively on the "Helder-Jahn" Tenor.

These sections are based on their first experimentations with the Helder Tenor in combination with electronic sounds composed by Gerriet K. Sharma which include also samples of Susanne Fröhlich playing the Helder Tenor.

Working trough a sort of „list“ of each of them, they at the end could create their „compositon-list“. This list could then be put into a time frame and compositional form.


to play counterpoint
to have a dialog
to start/trigger
to stop

The biggest challenge for both of them was to develop a piece with an electronic device as second performer on stage.

Sharma who has written several papers proving the instrumentality of the IKO and its ways of orchestrating space, was now confronted with a task which could nihilate everything he found out within one performance. But the contrary happened. Already in their first session Susanne Fröhlich got the feeling of playing chamber music, perceiving the IKO not as a usual loudspeaker, but rather as a colleague and partner on stage. This was only possible due to Sharma’s expertise on how to perform with the IKO as well as his ideas and openness to bring the IKO into context with another live-performer, understanding both instruments as sound projectors that make sound spatially tangible.

During their working process they got more and more aware of how and how much the Helder-Jahn Tenor can interact with the IKO. What felt first as a complete reduction of Fröhlich’s physical presence, turned out to reach the maximum concentration and optimum balance in presence and sound quality of both performers, of course depending on the scene and dramaturgy. They for example realized as soon as the IKO starts to make a lot of movement on stage, the physical body can allow itself to movements as well, but always in relation to the IKO.

This had also a great impact on the placements of the body on stage.

They were experimenting a lot with transitions from one section to the other, thus from position to position.

At the end Sharma and Fröhlich choreographed the whole piece following the dramaturgy of the music, creating an overall sensual experience. The next challenge was then to dare taking freedom and risks again, to make every performance a unique event, no show being alike.