The Untempered Cosmos

A live, mathematically-tuned chord drawn from the stars and planets currently above your horizon. The sky changes. The sound changes with it.

The Untempered Cosmos is not a song. It is closer to a wind chime, or a fountain, or a room with a good view. You put it on and let it run, and over time you start to hear what it is doing.

Preview it now at theuntemperedcosmos.com. The app turns the piece into a room you can stand inside: each star anchored to its real position overhead, the chord holding still as you turn.

When you open it, the app reads your location, looks up which stars and planets are above your horizon at that moment, and assigns each one a sustained sine tone. The brighter the object, the louder. The higher in the sky, the more present. Each tone is placed in the space around you to match where its object is in the sky. As the Earth turns, stars rise and set, and the chord changes with them.

There is no playback in the usual sense. Nothing is recorded, nothing repeats. Two people listening at the same instant from different cities will hear something different. The same listener returning at midnight will hear something different from what they heard at dusk.

The piece is tuned to a single low D, with every audible tone a whole-number ratio above it. This is just intonation, the tuning choirs drift toward when no piano is forcing them to compromise. Sine tones have no harmonics of their own, so the only thing creating consonance between two of them is how cleanly their frequencies divide into each other.

Eighty-eight objects: the Sun, the Moon, the five naked-eye planets, and eighty-one named stars down to magnitude 2.5. Each constellation is treated as a chord and tuned with intent. Some carry shimmer pairs, two stars detuned by fractions of a hertz so they beat slowly against each other.

Best on headphones. The spatial design places each tone in three dimensions. On supported AirPods with iOS 18+, head tracking holds the chord locked to the world around you, so the stars stay where they are as you turn.

By R. Andrew Lee. A work in progress; the catalog will keep growing.