Mesa Musical Shadows is the most recent interactive piece by Montréal’s venerable Daily tous les jours studio. Unveiled this past spring, the “singing pavement” is installed in the north plaza at the Mesa Arts Center in Arizona. True to it’s name, shadows cast within the sensor- and speaker-laden plaza trigger melodic and percussive sounds, allowing individuals and groups to engage in spontaneous exploration, play, and composition across the geometrically tiled surface. “Sound – and in our case music – is of course a universal language,” Daily tous les jours co-founder Mouna Andraos says of the plaza’s universal appeal. “It helps us reach as wide an audience as possible. As an interface, it allows for immediate feedback, regardless of the time of day and speaks less to our cognitive brain and more to our emotions.”
Controlled by a MaxMSP patch linking Arduino Mega boards via OSC, Mesa Musical Shadows features four modes which change depending on the time of day. Morning, midday, evening and night scores were composed by sound designer David Drury to reflect varying atmospheres and — pragmatically — shadow lengths throughout the day. “The morning track, when shadows are still long and stretched out is slower and more ethereal; the midday track plays with very small shadows, and is made up of short percussive and dynamic sounds; the dusk track brings back longer sounds, for longer shadows that trigger a lot of elements at the same time, that bring together rich harmonies that compliment one another when they are superimposed.” The sensors constantly recalibrate themselves in order to define new threshold values to determine what is a shadow and what is not. And since one can’t count on there being shadows 24 hours a day (and sometimes it is overcast) sounds are also triggered when the sensors are stepped on.
Originating from a robust public consultation process, workshops helped the studio collect feedback and ideas from community members and Arizona State University architecture students.“From simple post-it notes to fully interactive mats, we brought different prototypes on site to get direct feedback and help refine the project,” Andraos says of the hands- and body-on sessions. “These consultations helped us figure out what the project’s essence had to be and hopefully the results honour that process and reflect the community’s various contributions.”
The installation’s 47 sensors are run through six control nodes, comprised of an Arduino Mega, ethernet shields, and custom connector shields – each of which is protected in a waterproof enclosure, placed underneath the tiling. Each sensor unit has a custom PCB with a light sensor on top and an LED on its bottom, for nighttime illumination and the more sensitive gear (computers, amplifiers, etc.) is all installed in the museum.
One of the major design challenges of Mesa Musical Shadows was determining how to install the speakers underground. An “out of site out of mind” kludge would not cut it, as the installation needed to pass city inspection. Furthermore, the selected speakers were weatherproof not waterproof and even in Arizona it rains sometimes – like the sensors, they needed to be protected – so the audio was bounced off a 45° deflection plate, to keep the speakers safely tucked away from the path of any water that enters the assembly through the grill.
When questioned further about the project’s engineering Andraos brings the discussion back to first principles. That intricate assembly is executed with an effect in mind, right? “Sound provides simple straight-forward rewards for the least engaged, or first time participants, but also allows for a gradual increase in the level of interaction as people choose to further explore.” In carefully calibrating the plaza it becomes a (literal) platform for experimentation, and this is where Daily tous les jours is rewarded: in sitting back and listening. “From the office worker who stumbles on the plaza by chance and takes an extra step or two to play along, the group of bar hoppers who spend an hour playing together in a semi-organized fashion, or even young teens on their bikes strolling around creating more unusual shadows … it’s the variety of people and their experiences that are always the most exciting to us.”