(Photo credits Kristin Warfvinge)
“Polifonia liquida” (liquid polyphony) is a new sound and light installation exhibited at Inter Arts Center for the Gallery Night of Malmö (Sweden) on the 26th of September, 2015. See this previous post for some close-up pictures.
The work involves a series of 8 independent audiovisual systems (arranged as two groups of three and five), each one composed of a sound actuator (a contact speaker capable of inducing vibration into surfaces) and a point light source that passes through a water-filled plexi plate and projects the vibration-induced shape modifications of the water surface on the wall.
This project has a strictly musical focus: the compositional process takes into account both the sound material and the visuals generated by sound. Issues are raised in terms of relationship between the sonic and the visual perception, about the choice of the frequencies in relation to the images they will create and about the delay between the sound input and the visual response.
Eight independently-controlled Mighty Dwarf 26W vibration speakers (capable of low-frequency response) are equipped with custom-made plexi plates (laser-cut at FBRKN, in Malmö, and made concave thanks to a hot-air gun). These plates host a certain amount of water, which reacts to the frequency sent to the vibration speakers. Eight point-light sources (modified IKEA Jansjö LED lamps) project the shadow of water ripples on the walls of the venue. These lamps are turned on and off at will by a timed dimmer.
The work explores the idea of visualization of sound from a strictly musical perspective. The installation is not a bare game of more or less defined Chladni patterns but wants to investigate a possible re-contextualization of compositional parameters, structures and processes in the frame of an audiovisual system that is partly physical, and for this reason depending on the physical qualities of the materials involved. The response time of water to the vibrating stimuli is a fertile constraint that influences the development of the sonic and visual material along time.
There are some crucial musical aspects that have been explored — even partially — in the making of this installation:
- tension between monophonic and polyphonic gestures, controlling how independent each audiovisual system is from each other (not only in the rhythm parameter, but also in the frequency and amplitude domain, thus greatly influencing the visual result);
- tension between solo and tutti, also offering different subdivisions of the 8-elements ensemble and creating a dialogue between the groups and/or the soloists;
- time-related processes, typical of renaissance music, such as dialogue between two parts (“cori battenti”), canons and so on;
- figures of space, letting the sound and the images travel through defined paths in the exhibition space.
Another level of presence-absence of material is given by the DMX system switching on and off the lights (DMX controller+dmmer). In this case the tension between darkness and light is a filter on the visual aspect of the work and acts in the same way than the sound-silence dichotomy. Silence is not used in the installation; instead, high-pitched sine waves have been employed, for two reasons:
- to create a complementary (in pitch) material to the low frequencies needed to make the plates vibrate (silence would have been too “absent” and to similar to certain low sounds which are not perceived as belonging to the center of our optimal auditory space);
- to prevent the listener’s ear from getting used (and tired) of the prolonged presence of the low part of the audible range, thus giving the listener a sort of “blank space” — actually a dark space, being the high frequencies always associated with the shutting down of the lights (since the “ensemble” was considered as a sum of three plus five audiovisual systems, it happened that only three or five of the lights were off while the others were on, so in those cases the room was not completely dark).
Until the realization of the final project, many tests with synthetic waves (sines, square waves, …) have been carried out with different materials in order to visualize the shapes of the water surface. The best result was obtained with plexi plates. I recorded some test videos in which different frequencies and materials produce different results. Some of those videos are available clicking on these links:
- glass bowl;
- plastic CD spindle case;
- plexi surface (a little thicker than the one used in the final project);
- plexi surface, final version.