Upstairs the main space of the Pavilion was a 90-foot
diameter 210-degree spherical mirror made of aluminized
mylar. The artists conceived of this space as performance
area that could be used by many visiting artists during
The mirror fulfilled all our expectations. Our architect
John Pearce devised an ingenious way the mylar mirror
could be fitted inside an air tight cage structure. A
slight vacuum of less than 1/1000 of an atmosphere, which
could be handled by a couple of good sized fans, would
be sufficient to hold up the mirror. By having a negative
pressure air structure, there was no need for cumbersome
This optical effect in a spherical mirror of producing
a real image resembles that of a hologram. The difference
is that because of the size of our mirror, a spectator
looking at an image could walk around the image and see
it from all sides.
The space in the mirror was gentle and poetic, rich and
always changing. It was complex in spite of its simplicity.
We discovered new and complicated optical effects every
day. The slide to the right is projected upside down.
Once the visitors could see themselves as a real image
in the mirror, the reaction was incredible. It created
much more excitement than we ever could have expected.
David Tudor designed the sound system as an "instrument"
with 32 inputs and 37 speakers arranged in a in a rhombic
grid on the surface of the dome behind the mirror. Sound
could be moved at varying speeds linearly across the dome
and in circles around the dome. Sound could be shifted
abruptly from any one speaker to any other speaker, creating
point sources of sound. Or all speakers were capable of
giving out the same sound. The lights and sound could
either be pre-programed or controlled in real time by
the artists from a console at one side of the dome.
The floor was divided into 10 areas made up of different
materials, such as astroturf, rough wood, slate, tile,
asphalt. Through handsets, like the one held by the boy
in the left slide, visitors could hear specific sounds
on each different floor material. On the tile floor: horses
hooves and shattering glass; on the astroturf: ducks,
frogs, cicadas and lions roaring. These sounds were transmitted
from wire loops embedded in the floor.
Twenty 100-turn wire coils or loops 1 foot in diameter
were embedded under each of the floor sections and were
fed by tape recorders. The low frequency magnetic field
they generated was picked up and amplified through handsets
the visitors carried. The innovation in this system was
the use of a large number of coils for each area to obtain
an even distribution of the sound and not have sound spill
over to another area.