Model 260e

Duophonic Pitch Class Generator

The Model 260e Duophonic Pitch Class Generator consists of two independent, voltage controlled pitch class generators. (A pitch class generator produces a singular pitch in every perceivable octave.) Frequency modulation inputs and a five band spectrum-shaping facility are provided.

When switched to the "barber pole" mode, an internal computer takes over pitch control of both generators, and issues pulses for triggering an external envelope generator (a model 281e, for example), which in turn can drive a voltage controlled amplifier (like a model 292e dynamics manager). When the 260e's output signals are gated through the latter, Shepard tones and other auditory illusions (such as the tri-tone paradox) may be produced.

The rate of change is variable to 2.5 octaves per second in either direction, and is voltage controllable. Additionally, the pitch intervals can be adjusted from quarter-tones to tri-tones to continuous (for Risset tones).

With its multi-voicing, equalization, envelope shaping, and frequency modulation capabilities, you will find the 260e musically more interesting than the standard Shepard tone generator employed in perceptual psychology experiments.

The settings of the 260e can be stored and retrieved as numbered presets with a model 225e or 206e preset manager.