The Mathematical Transformation Of A Chapel: Q&A With David Letellier

Floating around in the Saint Sauveur chapel in Caen, France like some otherworldly entity, is the kinetic installation Caten by David Letellier. Unlike his previous installations Versus and Tessel, mechanical sculptures performing programmed movements in stark spaces, Caten is driven by simple motors and complements a more organic, sacred space.

The piece consists of 300 fine wires hanging from two ropes which are connected to rotating arms. As it shifts and glides at the mercy of gravity, looking like the ghostly belly of a whale, it guides the sound composition, a score inspired by medieval solmization prayers. The arching of the piece is a direct nod to the architecture of the chapel, while the ethereal aesthetic and the low resonating hum of the composition reflect the transcendental nature of the building.

In Letellier’s signature style, Caten is a physically simple structure that transforms a space with its presence, the minute details of its motion, and ambient sonic accompaniment. We caught up with Letellier to find out how he achieves these elements, and why his latest work sees a shift to a different setting.

The Creators Project: In Caten, you’ve used notably less technology than you have in your previous pieces. Was there any particular reason for keeping this piece technologically simple?
David Letellier:This was a site-specific piece. I have not been able to do any prototyping at this scale before, and we had only a couple of days to build it on location. It was a one-time shot, so I tried to reduce the complexity of technology involved as much as possible. There is no software for Caten, just four industrial worm gear motors, that’s it. Two of the motors are connected to relays which switch on and off from time to time in order to de-synchronize them and produce different shapes.

In order to determine the length of the ropes and the wires, I built a Rhino-grasshopper patch based on the catenary equation that computes the shape produced according to the size parameters of the church. This was a crucial point, as I could only enter the church four days before the opening, then take the measurements of the space, compute them with the patch on location, and come out with the three necessary dimensions—the ropes, the wires, and the rotating arms. The organizers provided me with ten motivated art students from the Art school of Caen. They built the net and tied the 600 nodes in two days. We used two kilometers of 3 mm black wires.

One of four worm gear motors.

You’ve also decided on a spiritual setting as opposed to a gallery. What was your thinking behind setting this piece up in a chapel?
The organizers of the Interstices Festival, proposed different locations to me. The space was the trigger to do the piece as it is—the slow motion, the lightness, the natural reverberation, the meditative atmosphere.

What is it about the catenary that interests you?
A catenary is the curve produced by gravity on a chain or a rope. It is the most simple yet beautiful creation of the forces of nature. It has been a serious mathematical and physics problem for a long time—the hyperbolic cosine function that describes it was only coined in the 17th century. From ancient Greece to now, this curve and the inverted catenary arch have had an immense impact on the history of architecture.

A sketch of Caten.

How does the accompanying audio relate to the physical component of the installation?
The composition is a slowly-shifting set of four notes/intervals generated by the movements of the rotating arms.The motors are fitted with piezo triggers. Each time the arm makes a full turn, it plays one of the first four notes of the Latin scale (Ut, Re, Mi, Fa ), with four sub-harmonics of the same notes, producing deep, low frequencies on the four channel sub-bass system. The sound source is a 1983 analog polyphonic synthesizer from Korg, bought on eBay.
I was inspired by a medieval prayer called “Ut Queant Laxis,” also known as “Hymn to St. John the Baptist,” used in the eleventh century to determine the names of the notes of the scale used in Latin countries.

The Latin scale.

You’re known for producing electronic music under an alias. Does the sound design for your installations come from the same part of your brain as Kangding Ray?
Kangding Ray? Never heard of him.

Your pieces are typically quite simple in appearance, but yet profound. What do you want people to walk away with after seeing Caten?
An abstract feeling of levitation. A synesthetic experience of sound and movement. The vision of a sculpture suspended to low frequencies

Are there any other settings you’re like to complement with an installation for a future project?
Maybe somewhere outdoors, a desert, or a former uranium mine…