Abstract: Classic organ sounds are produced by selecting plural loops of predetermined sound components, and combining the components in accordance with parameters readily adjusted by an operator, which parameters are maintained separately from the musical notes which are being sounded at any given time. In this way, the finishing of the organ sounds may be tailored to circumstances, such as particular organ sound qualities, particular organ styles and the like. Plural microprocessors allow organ sounds to be produced, and varied, in accordance with any desired finishing, under operator control.

Abstract: An apparatus for achieving the effect of air movement in instruments during replication and sounding of complex musical instruments by separating unstable frequency components, the quasi-periodic components, from stable fundamental and harmonic components, the periodic components, of compound voice waveforms, storing the respective component information pertaining to the quasi-periodic and periodic components in separate memory locations, and recombining the quasi-periodic component with one or more periodic components in appropriate fashion to form and sound the compound voice waveforms.

Abstract: An electronic musical instrument of a type wherein a plurality of systems are provided each system comprising memories storing respective harmonic component waveshapes which are read at the same reading rate and the read out harmonic waveshapes are suitably mixed to obtain a desired musical tone. Each system also comprises a circuit for controlling the envelope of the waveshapes read from the memories. In the first system, the envelope control is made in such a manner that the envelope will rise upon depression of a key, thereafter maintain a constant level as long as the key is kept depressed and decay upon release of the depressed key. In the second system, the envelope is controlled so that the envelope will rise in a short time and immediately decay thereafter. The respective harmonic waveshapes thus controlled in envelope in the respective systems are then suitably selected and mixed together.

Abstract: A percussion processor for an electronic musical instrument, such as an electronic organ in which information representative of the actuation of selected switches corresponding to associated notes of the musical scale is furnished in the form of a time-division multiplexed signal having repetitive sequences of time slots, includes a delay circuit comprising a shift register having a time delay period equal to the duration of one of the sequences of time slots or an integer multiple thereof. The multiplexed signal train is applied to the delay circuit and also is applied in parallel to an inverter circuit. The output of the inverter and the output of the shift register are connected to different inputs of a NAND gate.

Abstract: An electrical organ in which each of the keys of the organ is mechanically coupled to one single pole single throw electrical switch, and a plurality of said switches are each connected to a plurality of photoelectric tone sources through pulse shaping keying circuits, the keying circuits connected to each key switch being connected in a cascade circuit with the direct current potential source and the photocell of one of the tone sources, the other tone sources having photocells connected to the junctions of keying circuits in said cascade circuit. The tone circuits actuated by a given key of the organ may be at the same frequency or may comprise a chiff tone component or a noise-puff component, or may include a special decay circuit which activates a photocell modulated at a different pitch from the main-tone component.