Special effects circuit for an electronic organ

摘要

A special effects circuit for use in an electronic musical instrument, preferably an electronic organ, including a filter circuit having variable bandpass characteristics and a tone source supplying a signal to the input of the filter circuit. The bandpass characteristics of the filter circuit are modified in accordance with a control signal. Upon the occurrence of an input signal, a control circuit provides the filter circuit with the control signal at a random or pseudo-random value. The instrument player may select the source of input signals from a variety of sources within the organ thereby determining the times or frequency at which the control signal changes but the value of the control signal is random or pseudo-random. The tone signal output from the filter circuit has randomly or pseudo-randomly attenuated frequency characteristics and is coupled to standard organ output circuits for audio presentation.