The Very Large Array - FAQ
Q. What are those things on the ends of the VLA modules?
A. Those are speakers. Each VLA module emits a monophonic sound - due
to circuit exigencies, using two speakers turned out to be convenient.
Q. Is that little black thing on top of the VLA module a button?
A. No, it's a light sensor. Please don't press on it!
Q. Is the VLA solar powered?
A. No. Each VLA module has its own battery, which stores enough power for
about 5 nights of operation.
Q. I visited the VLA during the daytime, and it wasn't working. What's
wrong with it?
A. The VLA is quiet during the day, and makes sound at night.
Q. Are the VLA modules connected?
A. No. The modules of the VLA are completely independent.
Q. How does it work?
A. The VLA is based on a sound record/playback integrated circuit
Information Storage Devices. This integrated
circuit is like a tape recorder on a chip. In addition, each VLA
module contains an IR phototransistor for light detection, a battery, two
speakers, some random passive components, and a simple microcontroller
made by Microchip Technology Inc.
Q. Are all the sounds different?
A. The sounds are all different, but many similarities exist. I find
that using subtle differences between adjacent modules leads to
the most pleasing effect.
Q. Where do the sounds come from? How are they arranged?
A. Several arrangements of sound have been used:
Nov. 2, 1997 and before: various sounds of natural origin were used
to create a collage. Cosmic background noise, radio noise from various
celestial bodies, bird song, the whooping of gibbons, insect sounds and
dripping water all found a voice. The square grid of modules was structured
as concentric squares, with a tendency to have noisier, more random sounds
in the outer layers, and more musical sounds in the inner layers.
July 4, 1998 on Black Rock: 16 distinct but similar sounds were created
using the fmvoice instrument in the fine software synthesis
program, Csound, v 3.477. See
here for more
info on Csound.
Burning Man 1998: using the experience gained on July 4, I created a
much more complex set of sounds using Csound. The VLA was
arranged as 4
outer 4x4 grids around an inner 6x6 grid. Each 4x4 grid had a distinct
theme, with subtle variation among modules; the 6x6 inner grid contained
Csound-synthesized sounds, as well as a collage of sounds taken
from a recording made for me at Davenport Beach on Oct. 5, 1997.
Q. When will the VLA make its next appearance?
A. I have no current plans to set the VLA up again. The difficulty of
finding a proper location, the sheer work involved, and my disgruntlement
at the theft of 4 VLA modules at Burning Man 1998 argue against it. Maybe
on Black Rock in 2000!