Chorus

White branching lines radiate from a dark circular centre across the illuminated facade of Storkyrkan at night.

A sound-reactive work projected onto Uppsala Cathedral for Allt ljus på Uppsala in 2021 and onto Storkyrkan for Nobel Week Lights the year after.

Tove Alderin reached out through our mutual friend Sophia Wood. The piece played Dona nobis pacem alongside NASA's "Chorus", a VLF recording of electromagnetic waves in the Earth's magnetosphere. Anyone standing outside could sing into their phone and become a voice in the work. Pitch analysis at the Stockholm University Phonetics Laboratory drove particles that formed a pattern across the facade.

Both years we worked out of a freezing cargo container on the square, aligning the mapping as our breath fogged the laptops.

The tricky part was making hundreds of simultaneous voices still feel personal. With anyone in the city able to join from a phone, each singer needed to recognise their own particle, a few pixels moving the way their voice moved.

The work was created by Tove Alderin. I handled the projection mapping, composition and socket data. Mattias Heldner at the Stockholm University Phonetics Laboratory did the pitch analysis, Sol Sarratea wrote the shaders, David Giese did the video, and Scenteknik ran the rig in Stockholm.

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