Mark Esper

MATERIALS: Steel and wood pendulums with neodymium magnets, electromagnet coils with soft steel cores and polycarbonate structural parts, circuits with voice chips, speakers mounted in PVC pipe enclosures, and text.

SIZE: pendulums are nine or ten feet long; the twenty-four electro-magnet units are arranged in a circle eight feet in diameter. Beyond this circle are twenty-four speakers arranged in a circle of about twelve feet.

Gathered Voices is an exercise in self-organizing form through the use of coupled oscillators. It will generate a sort of music from a variety of recorded voices.
There is a phenomenon we are all familiar with; we remember the voices of people who are or have been close to us with perfect fidelity. Even if it has been decades since we last heard that person’s voice, the timbre and inflection of that voice is perfectly reproduced in our memories. To some extant, we are our memories. In this way we embody the personalities of even people long gone. These voices can at times form an internal music heard only by the one who remembers.
This is the text that is used in this project;

Voices are heard from where I am most still.
Not as intrusive ghosts to unseat peace,
But come invited as an act of will.
Listen within, old friend’s spirits release!

How true they sound, as if my ears behold
remembered friends as if each one were here.
Their very tone, timbre and cadence fold
into a deeply layered image dear.

Returning echoes paint a landscape felt,
of recalled sounds and texture of the soul.
All them in memory together melt 
And cast themselves into my own life’s role.

Gathered voices, some who have gone before
live still, and still speak to my inner core.

There are twenty-four units. Each unit consists of a pendulum assembly, an electromagnet, control circuitry, and a voice chip with a speaker.
Pendulums consist of an eight-inch by five-eighths inch lag bolt at the bottom of an eight-foot long wooden pole a half-inch square. The wooden pole is connected to the horizontal supporting ring with steel wire. At the bottom of the lag bolt is a powerful neodymium magnet.
The electromagnets are about four inches in diameter and seven-eighths an inch thick. They have soft steel cores one and five eighths inch in diameter.
Placed at the top of each electromagnet is a Hall effect device, which is a switch that is activated by the proximity of a magnet. When the pendulum with its magnet swings near the Hall effect device, the device switches two electrical circuits. 
One of the circuits that the Hall effect device switches is one that turns on the electromagnet for a brief pulse. A magnetic field is thus generated around the electromagnet. The polarity of the generated magnetic field is the same polarity as that of the magnet at the bottom of the pendulum. 
Because like polarity magnetic fields repulse each other, the pendulum is pushed a little by its interaction with the electromagnet, keeping its movement going.
The other circuit that the Hall effect switches is the sound component of the unit. It allows a pre-recorded voice reciting text to play on a speaker for a brief time, about a second.
Each of the twenty-four voice chips has the same text spoken in unison but with a different voice on each chip. There will be understandable continuity in what is heard, but the voices reciting the text will constantly change.
Because the magnets at the bottom of the pendulums are all the same polarity, the pendulums interact with each other because they repulse each other. They will fall in and out of patterns of movement. They are weakly coupled oscillators. In this way, the swinging of the pendulums determines a self-organized music out of the speaking voices.