Based on an idea by Gerhard Eckel, the Springer-Tempophone scenario design is prototypic for many EGM-scenarios and has a number of variations in tracked point placement, number of tracked points, and, in two basic versions, distinguishes between mapping absolute tracked point positions, or distances between them (relative tracked point positions), onto a window in a soundfile, with different soundfile placements across performance space. The Schwitters-scenario, for example, is based on a Springer-Tempophone prototype with sound material spanned across space in a single direction, involves the tracking of the absolute position of one point on the body, and uses an excerpt of Kurt Schwitters’s The real disuda of the nightmare as sound material.  Schwitters’s The real disuda of the nightmare is a piece of concrete poetry from 1946.[1]  The excerpt of approximately 9 seconds duration includes a number of fricatives (‘k’, ‘sh’, ‘ch’) together with some inhalation sounds. The sound generation algorithm is based on the method of granular synthesis and works as follows: a “window” into the above excerpt is repeated permanently. The size of the window is variable and ranges between 100ms to 22ms depending on the height (z-coordinate) of the tracked point.[2]  The window into the excerpt itself moves according to the horizontal position of the tracked point in performance space (x-coordinate). The looped sound material in the window is played at its original frequency. Effectively, one hears a short sonic moment being continuously prolonged. Motion of the tracked point means respective window motion. If one moves at the right speed continuously along the x-axis of the performance space, one traverses the entire material. Because of the looped sound in the window being played at a constant frequency, slow spatial motion does not lower the pitch of the sound as one might first expect. The mapping in this scenario is thus one from performance space (x-coordinate) onto window position (t-coordinate in soundfile). It is a case of direct linear mapping. The specific Schwitters setup presently described uses a second instance of identical sound material mirrored at the centre of the stage onto the other side. 12 metres of performance space are thus mapped onto 18 seconds of sound material: to traverse 1m in space is to traverse 1.5 seconds of sound material, or, inversely, one second of the excerpt is traversed in 75 centimetres’ motion.[3] 

The instrumentality in the above design could be described metaphorically as a type of “reading” or “traversing” the sound material spread out in space. A good comparison is the functionality of a head of a tape recorder: imagine dismounting the head of the device and directing it manually along a magnetic tape hung through space (a comparable installation by Nam Jun Paik was Gerhard Eckel’s inspiration to this instrumental notion behind the scenario). Add to this that the head is rotating, like the head of a Springer-Tempophone. The rotating head means that the pitch of the sound material heard stays constant, independent of the speed in which one moves along the tape. Now think of the rotating head and the hanging tape as invisible and immaterial. Moving the tracked spot on your body alone will mean to read or traverse the sound material as spread out in space. Without any physical contact with the sound source, a performer may thus exert minute control over time within waveforms. As motion along the depth of the performance space (that is, along the y-axis) makes no difference to the window position in the sound, there is much freedom in the way a performer may use spatial movement to achieve similar soundsequences. An even higher realm of potential movement without it being sound-producing action is due to only a single spot being tracked – if this spot is the top of the head, for instance, arm motion is (except for tiny but important indirect movement) nearly free. Simply put: moving towards the left side of the space will result in the sound excerpt being played forward in time, and moving towards the right will effect motion backward in musical time.

Different scenarios derived from the Springer-Tempophone prototype are: (1) Schwitters (single line, absolute); (2) Schönberg  and Lachenmann (single line, relative); (3) Delay (single line, absolute, delayed sonic response); (4) Cage Cross (two perpendicular lines, absolute); (5) Delay Cross (combination of 3 and 4); and (6) Boxes (numerous blocks of sound material positioned variably in space).


Peters’s idea behind the Spheres scenario (earlier called “perforation” because of its interior texture) was to (1) have a definable “timbre-space” in which a performer’s movement direction, speed and location could be discerned via smooth changes in sound quality which would still leave the impression of one being in a continuous space (rather than an architectonic structure) intact; and (2) to explore and improve the sonic-haptic illusion effect discovered in the Schwitters scenario, by realising it within a 3D-volume, and by giving it a varying tactile texture. The following attributes achieved this: The Spheres scenario features a variable number of volumes in the shape of circular or elliptic spheres. A sphere’s shape can be stretched from an even globe to a tube. It can be freely changed in size and positioned in performance space, even with its centre below floor level. A setup can include any number of spheres (a good balance was found with three spheres, one rather small, one medium size, and one large, each placed at different heights and in different areas of the stage; another interesting setup has spheres intersecting each other, disappearing partly into the ground or hanging partly out of reach). The sounds within each sphere are generated via FM-synthesis (frequency-modulation synthesis). The three spatial coordinates (Euklidian space) are mapped directly onto three FM-synthesis parameters (brightness, “roughness”, and fundamental pitch), with extremes of parameters matching the extremes of the sphere.

In effect, each sphere encloses within its volume a sort of timbral “colour wheel”, giving its interior space a smoothly changing timbral shading. To have a clear impression of the speed of traversing a sphere, and to make for a haptic effect, a sphere is perforated by holes with flexible overall size and distance (e.g. a sphere might be regularly  and symmetrically perforated with holes that are 5 cm in diameter and 15 cm apart in all directions). To have varying pseudo-tactility within a sphere, the “holes” are fully silent in the sphere’s centre, and becoming filled with sound (same as would be expected at the particular location within the general continuum) towards its surface. Sounds in a sphere have an even loudness throughout, except for the surface. Within an outer shell (definable in its thickness) ending in the immediate surface of the sphere, the overall loudness fades out, so that in approaching and entering the surface the sounds loudness gradually increases. Dancers (esp. Alex Gottfarb) have described the effect as that of a “membrane”, with varying levels of “fluffyness” and resistance.


[1]     Eberhard Blum, Kurt Schwitters Ursonate, The Real Disuda of the Nightmare, Ribble Bobble Pimlico, Ri
Ribble, Therwil 1992 (CD Helikon Hat 6109)

[2]     The shortest grain is 100ms (on the floor), the longest 22ms (at and above 2m height). Between this, the duration rises with the target height exponentially.

[3]     This proportion is due to a particular choice in scaling. The scaling between spatial and temporal change could of course be varied so that, for example, 50 seconds of sound material could be traversed in 2 metres. This, however, would mean an extreme zoom out of the sound material’s detail, or, in case of an opposite choice (1 second traversed in 10 metres, say) an extreme zoom into the fine-grain of the sound material. In each case the character of the appearing sound and its manipulation changes dramatically. The present aesthetic choice was motivated by the wish to have an identifiable phoneme Gestalt within the dancers’ gestural range, to precondition an intermedial playing with dance-supporting spatial distribution and some preservation of the original sonic character of this performance of The real disuda of the nightmare. The speed of traversing the scenario so that the material is heard in its original tempo is 0.67 metres/second, which corresponds non-hurried gestural or walking pace. This was empirically determined, using the dancers’ judgement of the workability and aesthetic interest of the scaling.