Echo Moiré by Matteo Marangoni

robot loudspeaker sound movement space
The two sonic vehicles used in Echo Moiré by Matteo Marangoni © Matteo Marangoni

Echo Moiré (since 2011) by Matteo Marangoni is an exploration of space, sound and movement in the form of a robotic opera ballet. Two sonic vehicles drive around the space. These two robots perform a sophisticated choreography, gradually investigating the audible responses of the room and creating complex patterns of acoustic reflections. The title Echo Moiré is referring to these patterns, in the visually domain called Moiré patterns. These patterns occur by overlaying two images containing black and white stripes or other motives.

moire pattern
A visual Moiré pattern.

To create sonic patterns manipulated by the acoustics of the space Matteo used two vehicles emitting sound to create similar phenomena in the audible domain. Simply said these vehicles are loudspeaker horns on wheels. These speaker horns diffuse the sound very directionally and are therefore very suitable for discovering and playing the acoustic qualities of a space. He made three different sizes of them. The smallest ones (see pictures below) were prototypes and are not used any more. The medium and big sonic vehicles are both performing, depending on the size of the space; the larger pair is used for the larger space, and the medium pair for smaller spaces. Similarly as you need a bigger PA for a larger room, you need a larger and quicker robot to play a larger room.  The larger pair of robots has different horn sizes, one horn being slightly larger than the other, which results in slightly different resonances.

sonic vehicle robot sound movement space
The small sonic vehicles used as prototypes. © Matteo Marangoni
robot sound movement space
A medium-sized sonic vehicle for smaller spaces. © Matteo Marangoni
robots sound space movement
The largest sonic vehicles (a male and female, with different horn sizes). © Matteo Marangoni

The robots are built with speaker horns, small audio amplifiers, geared motors, wheels and batteries. Since the horns are very energy efficient, only a relatively small amplifier and battery is needed for a loud result. An arduino board with dedicated motor controllers and encoders controls the wheel movements. The Sense/Stage system developed by Marije Baalman is used to connect the arduino wireless to a computer. The audio is transmitted wireless as well, and  from the same computer, which makes it possible to perfectly synchronise movement and sound of the robots. The whole performance is played by Matteo in real time from this computer using midi controllers. The movements and sounds created by the sonic vehicles are all programmed in the music software Max.

The choreography and composition have “fixed overall structure, but it is always adapted to the space, the robots play the architecture, so it’s never the same in two different places.” All movements and sounds are composed for each other and therefore inseparable. The sonic vehicles play the space. As Matteo explains: “the sound I send out from the loudspeaker is not very interesting at all, what makes it interesting is the interaction with the space. In the first 5 minutes I am just basically scanning the room with one rotation, listening to how the sound changes based on the direction of the speaker. I then adjust the sound that I am emitting to highlight certain characteristics of this sound-movement interaction.” The starting point for this seems to be Matteo’s interest for sonic reflections in spaces, and how audible features can trigger new ways of awareness: “I find great pleasure and amazement in listening to how sounds echo in the open spaces of a city, or how gradually scanning the acoustics of a completely dark, silent and reverberant room can open up a totally new way of perceiving a space.” (as he explains in this  interview on his work by DIGICULT).

The loudspeaker robots are exploring the space, as Matteo explains clearly: “I use them as projectors, to illuminate the space, which is something very different of using them to reproduce or amplify a sound. You can think of this as the difference between a film projector showing a movie in a cinema and a flashlight that you use when you go camping, they are both making light but the similarities end there.”

These are some excerpts of the 20 minutes performance:

The video below of the complete choreography of the performance (20 times sped up) gives a good impression of how carefully staged the performance is. In contrary to for example driving vehicles like toy cars, these ones really seem to know where they are going, and create a real ballet (look at the virtuosic pirouettes in the end!). Evidently Echo Moiré can only be experienced by being there, sharing space with the robots and especially discovering by ear what would not be audible without them. During their performance the robots open up our ears and make them extremely sensible for sonic phenomena of resonance and echo in the performance space. As an audience the composition guides you through beautiful ways of using your ears, which are not only very different as the one we use in our everyday life, but can also only exist in this purposely designed situation.

Thank you, Matteo, for answering my questions!