An analog sample playback machine, similar in basic concept to the Mellotron. The Optigan was originally produced by toy maker Mattel, starting in 1971. In 1973, Mattel sold the rights to another company which continued production until 1976.
The Optigan used a clear Kodak mylar or acetate(?) process to create disks as its playback medium. Waveforms were encoded on the disk as light and dark variations, in the same manner as a movie film with an optical sountrack. Each disk contained 37 note samples for a particular instrument, each of which was mapped to a note on the three-octave keyboard. Additional tracks were dedicated to the chord buttons to the left of the keyboard, plus some for intros, variations, vamps, and percussion, all of which could be triggered by panel switches. Variation of the tempo on these tracks could be done by changing the motor speed; however, this of course threw off the pitch of the other tracks. The instrument held only one disk at a time, so to change sounds, the user had to stop the drive motor and change disks.
The Optigan was designed as a mass-produced home amusement, and was not meant to be used by professional musicians. As a result, there were a number of compromises in design which gave the Optigan a reputation as a "cheesy" instrument. The fidelity of the optical playback system was poor, and the quality of plastic used for many of the disks was also poor, which resulted in surface noise akin to vinyl phonograph records. All of the instrument note and chord tracks were looped and the disk spun continuously; this made it difficult to reproduce the sound of plucked-string and percussion instruments since the user had to watch the built-in metronome to know where the note attack was, and playing syncopations and odd time signatures was only feasible with using non-percussive sounds such as strings and organs. The selection of chords on the chord buttons was incomplete and common keys such as E and A could not be played without changing the motor speed and then transposing. The motor drive mechanism was cheaply built and unreliable, and the disks did not hold up well to heavy use, tending to stretch out of shape.
Nonetheless, the Optigan has seen a certain amount of cache among performers looking for something different. A group of owners and collectors has developed software that allows new disks to be printed using transparency media and laser printers, making a much wider variety of sounds available. In the late 1970s, Moog Music's David van Kovering developed a professional version called the Orchestron, with an improved drive mechanism and electronics, glass disks, multi-disk capability, and features such as envelope generators, VCAs, and VCFs for improved sound shaping capability.
Tricks: Extremely slow speeds can create ominous tones with some orchestral disks. Placing two copies on a spindle out of alignments creates complex waveforms. A disk can be placed upside down to reverse envelopes, but sadly many disks use a simple on/off square waveform which is the same either way, however banjo sing-a-long (used by Devo) does not. Sought after disks include big top circus, banjo sing-along, some country disks and vocal disks and anything orchestral, such as polynesian village. Pea Hicks prepared a sold out series of unusual modern disks at Optigan.com.