|AudioMulch Help > Contraption Reference > Signal Generators
Synthesizes a continuously ascending or descending tone.
RissetTones produces the acoustic illusion of a gliding tone (glissando) that seems to move continuously up or down in pitch in one direction. The tone is created by mixing a number of sine wave oscillators together.
See the Adjusting Contraption Properties section for information about using sliders, knobs, presets etc.
Controls the speed and direction of the frequencies of the individual sine wave oscillators. Rate ranges from -5 to 5 Hz. At 0 Hz (default) the tone is stationary. At negative rates (between -5 and 0 Hz) the tone sounds like it is continually descending. At positive rates (between 0 and 5 Hz) the tone sounds like it is continually ascending.
Defines the pitch spacing between individual sine waves in the tone in cents. The lower the Spacing setting, the greater the number of oscillators required to complete the acoustic illusion for a given Range.
Defines the upper and lower frequency limits of the tone. The wider the Range setting, the greater the number of oscillators required to complete the acoustic illusion for a given Spacing setting.
Defines the maximum number of oscillators used to synthesize the tone. Lets you limit the number of oscillators in use at one time, helping avoid CPU overload. The recommended number of oscillators is displayed to the right of the text box. This number will ensure that the illusion is maintained. A lower setting than the number recommended may result in irregularities or gaps in the tone, which will spoil the illusion. A higher setting has no effect on the quality of the illusion. However, lowering this number will help prevent CPU overload while adjusting other parameters.
Relevant Example Files
The following file provides an example of how RissetTones can be used:
To open the Example Files directory, go to the File menu, select Open, and double-click on the Examples folder. Read descriptions of the example files here.
The RissetTones contraption is based on the acoustic illusion originally developed by Roger Shepard in the 1960s and later developed by Jean-Claude Risset. The Risset tone illusion has been likened to the aural equivalent of the “barber shop pole” on which spiraling lines appear to continuously move from one end of the pole to the other as it spins.