The
Optigan was a kind of home organ made by the Optigan Corporation
(a subsidiary of Mattel) in the early 70's. It was set
up like most home organs of the period- a small keyboard
with buttons on the left for various chords, accompaniments
and rhythms. At the time, all organs produced their sounds
electrically or electronically with tubes or transistors.
The Optigan was different in that its sounds were read
off of LP sized celluloid discs which contained the graphic
waveforms of real instruments. These recordings were encoded
in concentric looping rings using the same technology
as film soundtracks. (Remember that sequence in Fantasia
where the Soundtrack makes a cameo? Those squiggly lines
are actually pretty close to what the real thing looks
like.) As the film runs, a light is projected through
the soundtrack and is picked up on the other side by a
photoreceptor. The voltage is varied depending on how
much light reaches the receptor, and after being amplified
this voltage is converted into audible sound by the speakers.
The word "Optigan" stands for "Optical
Organ."
Optigan
discs have 57 rings of soundtrack- these provide recordings
of real musicians playing riffs, chord patterns and other
effects. (37 of the tracks are reserved for the keyboard
sound itself- a different recording for each note.) So
when you want to play a bossa nova, you don't get those
wimpy little pop-pop-chink-chink electronic sounds- you
actually hear a live combo backing you up! The problem
is that you only have a limited number of chords to choose
from- C, D, E, F, G, A and Bb major, plus their parallel
minor and diminished counterparts. (Actually, E and A
major don't really count, because for economic reasons
(or maybe avant-garde musical reasons, depending on how
optimistic you are) they decided to recycle the D diminished
chord for E major and the G diminished chord for A major.
I guess they felt that most of the notes matched anyway,
so why waste the extra disc space? Consequently, playing
anything in A or E major sounds really questionable at
best.)
Playing
back recorded instruments was a pretty unique concept
for the early 70's. Technically speaking, the Optigan
was a primitive sampler. Sort of. I tend to think of it
more like a poor-man's Mellotron
or Chamberlin. These are two famous keyboards from the
sixties which played back recordings of instruments on
lengths of magnetic tape. They became very popular despite
some huge drawbacks. For one thing, the tapes only lasted
a few seconds and, in the case of the Mellotron, could
not loop. If you wanted your flute to keep playing, you
would have to re-press the key after eight seconds. This
also involved waiting for the tape to rewind, so up-tempo
playing was generally not possible. Also, the racks of
tapes themselves were pretty huge and unwieldy- changing
from a choir to an oboe could take quite some time. Not
surprisingly, these instruments were quite expensive to
buy and maintain. But the sounds they made were worth
it- and apparently still are, seeing as the current street
value can easily exceed $2000.
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