Cbs Corporation

Marmon Company

Paul H Sharp

Donald J Leslie

A stereophonic electronic organ system having two electrical-acoustic channels each including a loudspeaker separated from the other, note generating means for producing for each note in a musical range two time-displaced electrical signals of substantially the same frequency corresponding to the note, and means for coupling one of the two signals for each note to one of the channels and means for coupling the other of the two signals to the other of the two channels. The two time-displaced signals for each note may be produced by providing two digital tone generators for each note and time-displacing one note from the other.

Stereophonic system for electronic organs

An electronic system for controlling the speed of a shaded-pole single-phase induction motor provides increased power during speed increase and automatic braking during slowdown by regulation of half-wave D.C. braking current applied to the motor. Speed control during normal operation, and braking control during slowdown and stopping, are implemented by means of dual feedback loops interactively connected to the gate electrode of a triac in the A.C. current line of the motor. The speed control loop utilizes a frequency/phase detector to adjust the time delay of triac gating relative to the zero crossing points of each half-cycle of A.C. voltage until the tachometer-sensed speed of the motor corresponds to a desired speed set by a voltage controlled oscillator. The braking control loop adjusts the time delay of the triac gating relative to the zero crossing points of every alternate half-cycle of A.C. power thus decelerating the motor by an impressed half-wave pulsed D.C. current.

Variable speed motor system

An improved mounting for an acoustic pulsato rotor for suppression of spurious sounds utilizes a spring bias for axial thrust between the shaft ends and bearing cups. In one form, a plurality of thin spider legs extend from a rotor mounting panel in surrounding relationship to the rotor to provide the spring characteristics while being acoustically transparent to the sound radiation pattern that sweeps past. The spider legs have a quick fit, anti-noise twist lock connection to a central hub. Improved rubber-like grommets provide anti-shock and anti-noise mounting for the shaft. Improved rubber-like grommets in cooperation with a two part motor mounting provide anti-shock and anti-noise motor mounting without sacrifice of simple belt tension adjustment capability. A light weight back enclosure for the speaker acquires sound isolation characteristics of a sturdy structure by imposing stress on the enclosure.

Universal pulsato unit

A signal animation system for an electric organ or other electrical musical instrument which utilizes frequency-proportional detuning wherein the percentage detuning is progressive and uniform, to provide celeste and other musical effects. Detuning is accomplished by a shift register through which sampled electrical representations of an input tone signal are shifted progressively through the register from the input to the output, which delays the signal. The trigger pulses which time the shifting function are frequency-modulated in a manner such that the period of the trigger pulses, rather than their frequency is proportional to a control voltage supplied to the trigger pulse generator. In a system for producing celeste animation, a shift register in each of two channels are controlled to progressively and uniformly phase-shift the musical signal in opposite directions simultaneously on a slow cyclical basis, and to produce abrupt reversal of the direction of phase shift of the two signals substantially simultaneously so as to provide two input signals one of which is slightly musically flat and the other slightly musically sharp for substantially identical periods at the end of which the two signals are abruptly reversed so that the first becomes sharp and the other flat. This cycle is repeated as long as a note is held, and when the two signals are acoustically combined, a very pleasing celeste is produced. In another embodiment, a shift register and modulator is provided in only one of two parallel sound channels which progressively and uniformly phase shifts the musical signal in opposite directions on a slow cyclical basis and produces an abrupt reversal of direction of the phase shift so as to provide an output signal which is alternately slightly sharp and slightly flat for substantially identical periods. When this output signal is acoustically combined with the unmodified tone signal, a musically acceptable celeste effect is produced.

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South Pasadena, CA, United States of America

Paul H Sharp