Archivi tag: sound

“Polifonia liquida” – sound and light installation (video documentation and project description)


(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).

(Thanks to Fabriken Malmö and its crew for plexi-cutting the discs. The work was hosted and created for Inter Arts Center Malmö.)


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:

Transforming a wooden floor into a multichannel sound system: “Wooden waves”, video documentation


Finally I prepared the video documentation of “Wooden Waves”, an installation originally conceived for the beautiful windmill of Harplinge, which is now turned into a hub for experimental arts (HarpArtLab), for the BZZZ! international sound art festival (July 2015).

(You may also take a look at the pictures I uploaded to a previous blog post.)

Eight contact speakers are attached to the floor’s wooden planks.

The listener lays down on the floor, transformed in a resonating surface.

Sound is perceived not only through the ears, but mostly through the body of the listener.

By stimulating the body in 8 different areas, a spatialization of the tactile sensation is put into play. This makes it possible to shift the use of space – typical of the electroacoustic composition approach – from the external dimension of the environment to the internal dimension of the body of the listener.

Tools for an enlightened dictatorship: embedding sound logos into people’s body

…or: territorialization of people’s body by means of soundmarks.

A soundmark is a landmark made of sound. In the frame of acoustic ecology, it characterizes an area, but in this very case it characterizes a body/a person. See the studies of Murray Schafer about soundscape and acoustic ecology, namely the book from 1977 The Tuning of the World (ISBN 0-394-40966-3), where he defines the soundmark.

  • Context

1. Let’s imagine a dictatorship (enlightened?) where every individual is forced to have a multimedia device installed in his/her body.

2. This device is controlled by the dictatorship and receives commands or data via wireless network.

3. The dictatorship decides to apply a particular sound (a sort of soundmark) to people, based on their behaviour. For example, tax evaders would be characterized by a special sound and everybody would recognize it.
4. The sound-logo may vary, depending on the behaviour of the citizen.

  • An example at Cittadellarte, November 6th 2015, 22:00
    (Performance by Alessandro Perini)

1. The logo of Third Paradise by Michelangelo Pistoletto, founder of Cittadellarte, has been rearranged so that the two symmetric curves, enchained one to each other, would form a sound wave:

2. This sound wave is a sort of DNA which generates a particular soundscape. Not only it constitutes the timbre of the sound (microscopic level), but it aso controls amplitude envelopes, pitch and rhythm structures:(2:30 excerpt from the generative sound environment. Note the accordion-like timbre derived from the Third Paradise logo-waveshape.)

3. This sound environment is worn by the designed individual, by means of a mobile device capable of receiving sound-streams wirelessly. Cittadellarte has incorporated his sound-logo into the inhabitant. The body of the inhabitant has been territorialized by a superior entity.

(A portable Bluetooth speaker was used in the performance.)

➥ A hacker could sneak into the software or the streaming system, so that the value of the soundmark could be sabotaged or tweaked.

This (provocative) project was elaborated at a residency module (2nd-6th of November, 2015) at Fondazione Pistoletto – Cittadellarte in Biella (IT), called Creating Territorialities (part of Unidee – Territoriality, Identity, Place and Possession; mentors G. Checola and T. Gliardi).

Cool patterns created on water surfaces by vibration

“Polifonia liquida”, sound and light installation exhibited at Inter Arts Center for the Gallery Night of Malmö (Sweden) on the 26th of September, 2015.

Eight plexi plates mounted on vibration speakers are filled with water, which receives the vibration.

Photo shots from a close distance show patterns created by vibration on the liquid surface.

General view of the installation.

Overview of the installation (Credit: Kristin Warfvinge)


Close-up at 23 Hz


Close-up at 24 Hz


Close-up at 26 Hz


Close-up at 28 Hz


Close-up at 30 Hz


Close-up at 31 Hz


Close-up at 35 Hz


Close-up at 43 Hz


Close-up at 55 Hz


Close-up at 56 Hz


Close-up at 64 Hz


Close-up at 72 Hz

Using a wooden floor as an eight-channel tactile sound system

BZZZ – International Sound Art Festival took place for the second time in the old windmill of Harplinge (near Halmstad, Sweden) from the 3rd to the 5th of July 2015.

I participated with a new installation, called “Wooden Waves”, in which eight vibrating devices were transforming the wooden planks of the 4th floor of the windmill in a resonating surface. People was asked to lay down on the floor to experience the vibrating waves and percussive sounds flowing along their body.
For now only some pictures are available, but a video and a more detailed post will follow during next weeks or months.




Touch my string. “Perturbance” for double bass and embedded electronics

Ghost studies, no. 2 “Perturbance” for double bass and embedded electronics

Jonathan Heilbron, double bass

47° Darmstadt Ferienkurse

August 15th, 2014, Kunsthalle Darmstadt

A series of three works with vibration devices embedded in musical instruments has been produced in the frame of the 47° Darmstadt Ferienkurse (“Expanded Music” workshop, coordinated by Simon Steen-Andersen).

The piece shown in the video is the Ghost Study number two, called Perturbance, and written in close collaboration with the double-bassist Jonathan Heilbron.

After a session with the performer, where I recorded a number of percussive interventions he made on the body and strings of the instrument, I reordered these gestures from the most inharmonic to the most stable spectrum (the A string of the double-bass). While building the electronic track (which was supposed to be played back through the vibration speaker), I created different reverberations of the percussive gestures. Some of this reverberations were infinite, and I could use them as static sounds which were triggered by the percussive interventions of the performer. The overall path of the piece lead to the final, loud 55 Hz sine wave emerging from some bowed notes. The A string was thus shaking, and placing the finger on the string made the timbre of the resonance change with the pressure of the finger. At the end of the piece, this resonance seemed to be stopped — as torn off — and re-activated by sudden gestures of the hands of the double-bassist “muffling” the whole instrument. Both this theatrical situation and the reverberations in the previous interventions were quite effective in giving to the instrument a life of its own. The interaction between the performer and the double-bass (the man and the artifact) was not anymore one-directional, but the instrument responded almost consciously to the stimuli of the instrumentalist, and seemed to make decisions of its own.

Being the instrument itself, and not a separated speaker, the resonating surface (electronic tracks can be sent to contact transducer embedded in the instruments) which emits sound, it’s often difficult to perceive (acoustically) the difference between an instrument played by a human and an instrument equipped with vibration capabilities. This way of augmenting the capabilities of an instrument leads to new possibilities in composition for instruments and tape and live-electronics, in a way reconsidering and reframing the live-electronics practice.

“Tactile headset”, listen with your head

This is the second work created at the residency at Park in Progress (Mons, Belgium), September 2nd-11th 2014. The other installation was “Subverted spatialization interface”, described in a previous post: check it out here.

“Tactile headset” is an installation that explores tactile perception of sound as vibration.


I built a cluster of four vibrating polystyrene spheres, hanging from the ceiling. Sound was traveling from sphere to sphere and the audience could experience it with the bones and skin of their head, as in a tactile quadraphonic headphone set. This work was a way to reference headphone listening (even binaural listening, since there were four sources), but translated into the tactile domain.


Picture by Zoé Tabourdiot


Picture by Zoé Tabourdiot

Spectral and vibration response tests on wooden planks

These are tests made on eight wooden planks (silver fir), ca. 10 cm wide, 2 cm thick, length variable between 150 and 230 cm. They were placed on a bubble wrap.

2014-06-18 10.55.39.jpg

I sent two different signals travelling through the eight vibro speakers (Mighty Dwarfs, attached to the planks via tape). Both signals were controlled via a Max/MSP patch (something between a drum machine and a granulator) which could modulate the pitch and amplitude envelope of each grain, and the duration and tempo over time.

1. Sine wave (varying around 60 Hz) continuously travelling from channel 1 to 8.

  1. Download here the 8-channel file used for the test.
  2. Download here the stereo mixdown of the previous file used for the sonogram.
  3. Download here the stereo recording (ZOOM H4) of the wooden planks resonating.

Sonogram of the original file (stereo mixdown):

Sine - clean

Sonogram of the resonating wooden planks:

Sine - wood

As you can see, the wood resonates with a lot of harmonics and side-noises (other objects were probably resonating as well) even if we send a “pure” sine wave.

2. Sawtooth wave, two sets: one around 60 Hz, travelling from channels 1 to 4; the other slightly higher (one semitone), traveling from channel 5 to 8.

  1. Download here the 8-channel file used for the test.
  2. Download here the stereo mixdown of the previous file used for the sonogram.
  3. Download here the stereo recording (ZOOM H4) of the wooden planks resonating.

Sonogram of the original file (stereo mixdown):

Sawtooth - clean

Sonogram of the resonating wooden planks:

Sawtooth - wood

Research mission

Tonight I’m starting this blog where I’ll post articles about my research project on tactile devices.
You can have a glimpse of the author at


THE MISSION (in short)

Contact speakers are sound devices which turn any surface into a resonant instrument. My research will focus on the possibilities given by the use of multiple contact speakers, connected with their tactile capabilities: multiple sources of vibration can stimulate our tactile perception in different parts of our body (what I call “spatialization of the tactile sensation“), for example if applied on a chair. Sound can then not only be heard, but also “touched”. Being able to separately control multiple vibration devices means also to identify spatial implications of sound movement, which opens up the path for an artistic use of the sound system.

On the other hand, making objects vibrate may lead to create even visual results…


This research project is funded by Kulturbryggan (Sweden). The activities at the Darmstadt Ferienkurse (August 2014) are also supported by Kungliga Musikaliska Akademien (Sweden).


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