Abstract: An ensemble effect is produced in a digital tone generator by providing a master data set of words having values corresponding to the relative amplitudes of equally spaced points along one cycle of a waveform of a musical tone in which the fundamental frequency is deleted. These values are read sequentially and repetitively from a memory to produce a first analog tone. A second analog tone is produced by multiplying a data set corresponding to the fundamental frequency by a low frequency sinusoid. The first and second analog tones are summed to yield a musical tone having an ensemble effect.

Abstract: A reverberation effect is produced in a musical tone generator of the type in which waveshape data points are sequentially and repetitively read out of a memory at a rate corresponding to the fundamental pitch of a musical tone. The reverberation effect is obtained by having a second memory storing waveshape points which are read out simultaneous with those from the first memory. The second data set is scaled by the ADSR envelope function and at selected echo time spacings is pointwise added to the data stored in the first memory. The data read out of the first memory is converted to an analog musical signal having a reverberation effect during the attack or release phase of the musical tone.

Abstract: An electronic musical instrument of the type producing pipe organ-like sounds including a circuit for simulating wind noise by causing a random perturbation from the nominal frequency of tune, which an organ flue pipe exhibits when sounding, through the use of digital noise generators which are utilized to approximate an analog white or random noise source. The digital noise generators produce digital noise signals which are used to frequency modulate the instrument tone generator to produce substantially random perturbations in tbe generator output signal frequency. The present invention may be used with musical instruments having a single tone generator system composed of either a multiplicity of oscillators with a vibrato input, or a top octave frequency generator integrated circuit and a single oscillator with a vibrato input, or a transposer system.

Abstract: A two-phase, period-proportional voltage-controlled oscillator circuit is provided for clocking an analog delay line which can be used, for example, in an electronic musical instrument. The voltage-controlled oscillator circuit provides two clock output signals of opposite phase and having a period directly proportional to the control voltage, i.e., the frequency of the two clock signals is inversely proportional to the control voltage. Since the delay provided by the analog delay line is directly proportional to the period of the clock signals, the delay is directly proportional to the control voltage thereby eliminating a source of distortion in a delay modulation system.

Abstract: A keyboard operated electronic musical instrument in which a number of tone generators are assigned to actuated keyswitches. When a keyswitch is actuated, a tone generator is assigned with a musical waveshape selected from a library of waveshapes which are ordered in a predetermined arrangement. The assignment of waveshapes is made in a priority order according to the musical frequencies associated with the actuated keyswitches so that a chorus effect is obtained in which each note of a group of simultaneous notes has its own tone color. The assignment of waveshapes is made in an adaptive manner so that the melody line retains its own distinctive sound even when the number of notes played simultaneously on a keyboard changes. Vibrato effects can selectively be applied to any of the set of waveshapes.

Abstract: A detuning control circuit is provided for producing a pitch variation effect in an electronic musical instrument. The instrument includes at least one integrated circuit tone generator chip having at least one tone generator and a detuning circuit responsive to a predetermined detuning control signal for detuning the signals produced by the tone generator. The detuning control circuit comprises a detuning control signalling circuit for producing a predetermined detuning control signal and for selectively applying the predetermined detuning control signal to the detuning circuit of the tone generator chip so as to produce a predetermined pitch variation effect.

Abstract: The present invention relates to economically fabricated means for the generation and processing, member selection, and acoustic radiation of pluralities of individual tone currents originating from at least one high frequency source and formed by note-information temporarily transferred through key depression, from permanent electronic memories to temporary memories in small numbers of standard tone units, in precise duplication of properties of pipe organ sound.There is described an electronic transfer organ for duplicating twenty-six known properties of pipe organ sound. The illustrative, inventive instrument employs completely standardized circuitry except for automatically programmable memories for each organ voice, which contain all the information required to form, switch and variously decouple all the notes in that voice.

Abstract: A continuously varying electrical signal representing an original musical sound is divided at a selected mid-frequency of about 800 Hertz to provide upper and lower frequency signal bands which are then frequency-modulated with separate modulation signals that differ in frequency or amplitude or both, in order to produce a vibrato or tremulant effect and thereby enrich the harmonic content of the musical sound.In order to inject the vibrato or tremulant into each signal band, the modulation process utilizes a pulse sampling and delay circuit which minimizes clock pulse noise by selecting only the central part of each delayed pulse, and which also senses the original amplitude envelope of the unmodulated wave in order to augment the envelope that is recreated from the delayed pulses after they are recovered.

Abstract: In an electronic organ including at least two frequency controlled delay circuits controlled by varying frequency output signals from individual voltage controlled oscillators, an analog modulating and intermixing circuit provides an even vibrato effect by controlling the input signal to the voltage controlled oscillators. The amplitude of a vibrato signal which is mixed with a main voltage control signal for a voltage controlled oscillator to provide a vibrato effect is modulated by the primary voltage control signal. The primary voltage control signal is amplified and passed to the control input of a voltage controlled amplifier which receives the vibrato signal. The amplified primary voltage control signal is mixed with the output of the voltage controlled amplifier to generate the control signals for driving the voltage controlled oscillators.

Abstract: An electronic musical keyboard instrument that is controlled by a digital processor. Key and stops/effects statuses are sampled, during successive time intervals, and read into random access memory associated with the digital processor. After manipulation and/or supplementation of the status information to effect implementation of various features, key-representative signals are read out to tone generation and voicing circuits.

Abstract: A timbre-select type electronic musical instrument in which the application of a sound effect unsuitable for the selected timbre is automatically blocked. This instrument includes means for detecting that a certain timbre is selected and means responsive to the signal from said detecting means for preventing the unsuitable effect for the timbre from being applied to a sound.

Abstract: The operation of the chorus generator of FIG. 3 may be summarized as follows. The generation of a realistic chorus tone depends upon the simultaneous amplitude and phase modulation of a tone signal which initially has little or no choral characteristics. When a tone signal generator is so modulated, the derived audio tone from a loudspeaker will exhibit choral characteristics. A random low frequency signal generator serves as an input to both the amplitude and phase modulation channels. The amplitude modulation signal is merely a suitably delayed replica of the low frequency signal. The phase modulation signal is derived from the low frequency signal by first modifying its amplitude excursions by means of a function generator and then filtering the derived signal by means of a suitable non-minimum phase shift filter.

Abstract: An electronic tone or note generator capable of providing improved musical and tone quality and special sound effects by mixing the outputs of a plurality of note-signal-producing circuits is provided. The electronic tone or note generator of the invention is characterized by the use of a primary electronic note circuit for producing a primary note signal which is a portion of a primary melody, and a secondary electronic note circuit for producing a secondary note signal that is musically related to the primary melody. The relationship between signals can be a time lag between the outputs of the two note signal circuits or a small difference in frequency between the signal outputs of the two note circuits. Additionally, each note signal circuit can output alternate notes of a continuing melody such that a note from one circuit may persist while the next note from the second circuit is played.

Abstract: An electronic musical instrument employing top octave synthesizer circuits (TOS circuits) for generating the musical tones to be reproduced by the instrument employs a single master oscillator common to all of the top octave synthesizer circuits for supplying the trains of clock pulses to the synthesizer circuits for their operation. To prevent phase-locked conditions from existing in the frequencies produced by different synthesizers, the clock pulses from the master oscillator are supplied to the synthesizers through coincidence gate logic circuitry which is controlled by means of a low frequency oscillator and a divider or shift register circuit to delete different ones of the clock pulses from the clock pulse signal trains for each of the different synthesizers. This causes all of the frequencies obtained from the synthesizers to be slightly different from one another, independent, and not phase-locked.

Abstract: A digital technique for triangular musical waveform generation is disclosed. A musical scale value corresponding to a selected note is repetitively added to produce an ascending series of non-consecutive numbers which is stored in a latch. A carry output from the limited modulus latch is used to switch a flip-flop which then enables an inverter to reverse the slope of the number series. Alternating reversals produce a rising and falling numerical staircase of controllable slope. This can be directly converted into a smooth triangular waveform, or alternatively it can be used as a series of memory addresses for table look-up purposes. The triangular waveform may be symmetrical, or it may have a controlled degree of asymmetry. Duplicate triangular waveforms with a small frequency mismatch may be used to produce a chorus effect. Or plural triangular waveforms with octavely related frequencies may be used as footages related to a single note, again with a slight frequency mismatch for chorus purposes.

Abstract: An electronic musical instrument of a partials synthesis type and the partials are processed in a time division multiplex fashion. One cycle of the time division multiplex sequence consists of a plurality of processing time slots, which are divided into two to four groups. Each group of time slots are used for processing partials which form a discrete musical tone. Thus two to four types of musical tones can be formed at the same time, which realizes an ensemble performance.

Abstract: When the frequency of an input sound signal applied to a shifting type echo-machine is close to that of the shift pulse thereof, a false signal appears at the output terminal of the echo-machine, in addition to the other type of noise signal caused by inclusion of the shift pulse component in the output of the same. The present invention is an echo-machine provided with first and second low pass filters, arranged before and after the delay element included in the echo-machine respectively, with a variable cut-off frequency which varies in accordance with the frequency of the shift pulse thereby eliminating such an erroneous signal and the shift pulse component from the output signal of the echo-machine.

Abstract: For generating tones in an electronic musical instrument, there are provided multiple master frequency sources, a different source for each octave, differing in frequency from each other by a factor which differs from two by at least one semitone, each of which is coupled to a respective frequency synthesizer all of which have the same dividing ratios, to divide down the frequency of its master frequency source to pitches of the twelve notes in the intended octave. In one embodiment the sources are separate master clock pulse sources, and in another embodiment a pulse train derived from a single clock pulse source is applied to the frequency synthesizer for the highest octave, and the pulse train applied to each of the other synthesizers is derived from the pulse train supplied to the frequency synthesizer for the next highest octave by dividing the pulse repetition frequency thereof by a factor which differs from two by one or more semitones.

Abstract: The disclosure describes improved apparatus for use in an electronic musical instrument having a keyboard including a group of keys corresponding to the notes of a musical scale. Electronic circuitry is used to generate simultaneously with respect to each of the keys first and second electrical tone signals, the repetition rates of which are detuned with respect to each other so that the sound of a chorus is simulated.The disclosure also describes circuitry useful in an electronic musical instrument having a keyboard including twelve keys corresponding to the twelve notes of a chromatic musical scale. The circuitry generates simultaneously a first series of twelve tone signals corresponding to a first tempered scale and a second series of twelve tone signals corresponding to a second tempered scale different from the first tempered scale.

Abstract: In an electronic organ of the time-sharing type, a single clock source drives a number of variable divisor frequency dividers which are assigned different divisor values to produce different musical tones at different times. In order to prevent phase synchronism between two simultaneously operating dividers, and thus achieve a rolling phase relationship which is perceived as a chorus effect, divisor values are employed for the two frequency dividers which are not in a whole number relationship. If the two dividers are generating octavely related notes, the divisors used have a ratio not quite equal to the nominal 2:1 value which musical theory requires. Moreover, the exact value of the ratio varies from note to note within each octave so that the rate of phase roll is not monotonously the same for all notes. Alternatively, if the two dividers are both generating the same note, then the divisors used have a ratio which is not quite equal to the 1:1 value which musical theory requires.

Abstract: A device for producing an ensemble effect in an electronic musical instrument. The device has a plurality of parallel electronic delay circuits adapted to be supplied with a musical tone signal, delay time modulating circuits coupled to each of said delay circuits for modulating the delay time in each delay circuit, a modulating signal generating circuit arrangement coupled to the delay time modulating circuits for supplying modulating signals to the respective delay time modulating circuits which are different from each other and the frequencies of which are in an integral multiple relationship to each other. Amplifiers are coupled to each of the delay circuits for amplifying the output thereof, and the amplifier outputs are mixed either electronically or acoustically.

Abstract: An ensemble effect is produced in a digital tone generator by providing a master data set of words having values corresponding to the relative amplitudes of equally spaced points along one cycle of the waveform of the audio tone. These values are transferred sequentially during repetitive cycles at a rate proportional to the pitch of the desired musical tone to a digital-to-analog converter for converting the master data set to an audio signal of the desired waveform and pitch. The ensemble effect is produced by transferring the words of the master data set to a second converter at the same pulse rate but having one value deleted or repeated once in the second set. Because the second set :has one less or one extra value in the set, the resulting audio tones from the two sets change phase with each successive cycle of the audio signals.

Abstract: A device for producing a chorus effect for an electronic musical instrument. The device has two sets of parallel time delay modulating circuits with each set having two circuits therein and the circuits being adapted to have the musical tones from the electronic musical instrument supplied thereto. Saw-tooth wave generators are coupled to the respective time delay modulating circuits for supplying the respective time delay circuits in each set with a saw-tooth modulating wave having a gradually increasing slope and a sharply decreasing slope, the saw-tooth wave supplied to one circuit in the set having the gradual slope increasing in the positive direction and the saw-tooth wave supplied to the other circuit in the set having the gradual slope increasing in the negative direction so that the waves in the set have opposite polarities, and the saw-tooth waves for one set of modulating circuits being 180.degree. out of phase with the saw-tooth waves for the other set of time delay modulating circuits.

Abstract: A two-speed motor drive system for an acoustic rotor includes two simple, relatively inexpensive motors cooperatively arranged to drive the acoustic rotor at either a pulsato speed or a slower chorus speed, and also to provide automatic braking of the rotor from full pulsato speed to either slow chorus speed or to a fully stopped condition.

Abstract: An electronic musical instrument system comprising an electronic musical instrument body and a separate tone cabinet connected together by a cable. The electronic musical instrument body includes a plurality of tone coloring circuits to produce different musical tone signals, a musical tone signal selection circuit to select at least one of the output signals of these tone coloring circuits, and a musical effect selector; and the tone cabinet includes a musical effect imparting circuit to impart the selected musical tone signal or signals with a selected musical effect, a sound system having at least one loudspeaker connected to the musical effect imparting circuit, and a control circuit responsive to the musical effect selector for producing control signals to cause the musical effect imparting circuit to impart a selected musical effect to the selected musical tone signal or signals.

Abstract: Apparatus for chorus effect in an electronic musical instrument in which a passing circuit for a musical tone signal is obtained from a musical tone signal generator by operation of a key. The passing circuit is connected to a plurality of variable delay circuits which are individually controlled by a plurality of delay control signals generated by a delay control signal generator. The passing circuit for the musical tone signal has a format filter, as well as a keying signal generating circuit. An output terminal of this keying signal generating circuit is connected to a voice production initial stage change control signal generator. The latter control signal generator has an output terminal connected to the musical tone signal generator or the delay control signal generator.

Abstract: This invention relates to tone generating systems for polyphonic electronic musical instruments. The system includes a plurality of programmable tone generators each of which is assigned to a different note to be sounded. For a preferred embodiment, one of the programmable tone generators is designated as a solo high tone generator, and is always utilized to produce the highest note to be sounded. Another generator may be designated as the solo low generator, and will always be utilized to generate the lowest note to be sounded. Additional solo note generators may be provided if desired. Tone generators are interconnected in a priority scheme with one generator at a time being designated as the next generator to be assigned a note to be sounded, and the designation being advanced in a predetermined manner as notes are assigned successively to the generators.

Abstract: A device for producing a chorus effect in an electronic musical instrument. An electronic delay circuit and a non-modulating amplifier means are coupled in parallel and the outputs are mixed in a mixing amplifier. A carrier oscillator is coupled to the delay circuit for controlling the time delay of the delay circuit according to the frequency of its output, and normally oscillates at a relatively high frequency in the range of 80-100 KHz. A modulation signal generator is coupled to the carrier oscillator for frequency modulating the carrier oscillator toward lower oscillating frequencies, and a control signal generator is coupled between the input to the delay circuit and the modulation signal generator for detecting the musical tone signal input to the delay circuit and producing a control signal only when a musical tone signal input is detected.

Abstract: Improved apparatus for use in an electronic musical instrument having a keyboard including a group of keys corresponding to the notes of a musical scale. Electronic circuitry is used to generate simultaneously with respect to each of the keys first and second electrical tone signals. The circuitry causes the waveshapes of the tone signals to deviate with respect to each other. In addition, the repetition rates of the tone signals are detuned and frequency modulated with respect to each other so that the sound of a string chorus is simulated.The disclosure also describes circuitry useful in an electronic musical instrument having a keyboard including twelve keys corresponding to the twelve notes of a chromatic musical scale. The circuitry generates simultaneously a first series of twelve tone signals corresponding to a first tempered scale and a second series of twelve tone signals corresponding to a second tempered scale different from the first tempered scale.

Abstract: A choral generator is formed from a plurality of delay channels, each including a modulated delay line which non-linearly varies the time delay imparted to a signal passing through it. The outputs of the delay channels are combined with the undelayed audio signal to form a composite output characterized by enhanced musical presence.

Abstract: Simultaneously played notes on a keyboard are automatically provided with different voice timbres. The assignment of voices to notes is by relative frequency-scale position within the chord. If four or more notes are played, the notes are scanned along the musical scale and the three lowest notes played and the highest note are sounded in different voices with the solo voice assigned to the highest note. Assignment of voices occurs automatically when fewer than four keys are played. One form of the system combines time multiplexed keying with priority coupling of the keying information to a plurality of voltage controlled oscillators through sample-and-hold memory circuits. Each oscillator has its own tone voicing circuits. In another preferred all-digital embodiment, the time division multiplex digital logic signals representative of the played keys are applied instead to a memory circuit and a comparator circuit.

Abstract: A musical ensemble effect results when two tones slightly out-of-tune with respect to each other are sounded together upon selection of a single instrument key. Herein, apparatus is disclosed for producing an ensemble effect in a polyphonic tone synthesizer of the type wherein musical notes are produced polyphonically by computing a master data set, transferring data set to buffer memories, and repetitively converting in real time contents of memories to notes. A multiplicity of master data sets are created repetitively and independently of tone generation by computing a generalized Fourier algorithm using stored sets of generalized Fourier coefficients. The phase of such master data sets are generated with time varying phase shifts to provide theout-of-tune ensemble effects. The phase shifted master data sets are combined and transferred to buffer memories from which such data is converted to musical sounds.

Abstract: In an electronic musical instrument, in particular an electronic organ, comprising a circuit for electrically modifying a musical tone by frequency modulation to provide an ensemble effect. The circuit comprises three series connected shift registers which operate as delay circuits and which are driven by three high-frequency oscillators. The oscillators are driven by three vibrato signals. The vibrato signals are out of phase with each other so that each of the clocks is driven by a differently phased signal. The outputs of the shift registers are filtered and are then recombined either electrically or acoustically or both so that a chorus effect is produced. Additionally, the output of the last shift register in the series combination may be fed back to the input of the first shift register in the series combination to introduce additional phase delay in the audio signal for richer ensemble effects.

Abstract: A pulsato generating system which is composed of a sequentially phase inverting signal generator for producing first, second and third sequentially phase inverting signals based on an input musical signal, a phase rotating signal generator for producing first and second phase rotating signals based on the first, second and third sequentially phase inverting signals and first and second speakers respectively supplied with the first and second phase rotating signals.Another pulsato generating system is disclosed which is composed of the abovesaid sequentially phase inverting signal generator and first, second and third speakers respectively supplied with the first, second and third sequentially phase inverting signals derived from the sequentially phase inverting signal generator.

Abstract: A circuit is shown for changing the frequency of a basic keyed oscillator by controlling the amount of keying voltage reaching the oscillator and the circuit used for vibrato. The purpose of this circuit is the achievement of true "pipe organ celeste" effect without using an added rank or set of oscillators. Circuits are described wherein the harmonic structure of the signal resulting from this modification of a basic keyed oscillator can be made to change by means of controlling the amount of keying voltage reaching the oscillator for the purpose of achieving the desired harmonic structure of the rank when operated in the "non-celeste" mode as opposed to the "celeste" mode. A circuit is also described for amplitude modulation and harmonic structure modulation at the vibrato rate to enhance the vibrato.

Abstract: This invention relates to a electronic chorus and tremulant system for an electrical musical instrument such as an electronic piano or an electronic organ. A plurality of different sub groups of tone signals representing musical notes are separately collected from a conventional tone generating system. A bucket brigade delay line vibrato system is incorporated in each of a plurality of transmission channels each having a loudspeaker at its output. The instantaneous pitch of the signals in each channel is cyclically varied by varying the time delay introduced by its bucket brigade delay line. The instantaneous pitch in each channel is caused to be different from the instantaneous pitch of every other channel so that a multiple voice chorus effect is produced.

Abstract: A circuit for producing a chorus effect in an electronic musical instrument. The circuit includes N separate channels, where N is an integer greater than one, with each channel having an analog delay line to which a tone signal is applied. Each delay line frequency modulates the applied tone signal at a subaudio rate in response to changes in the frequency of clock pulses applied to the delay lines. The delay variations in one delay line are out of phase with the delay variation in every other delay line by a selected amount which is normally 360.degree./N. Clock pulses are generated by means including a nonlinear circuit to compensate for the nonlinearity in the frequency interval between tones in the musical scale. The outputs from the delay lines after filtering of the clock frequency components are utilized to produce the desired chorus effect output from the instrument.

Abstract: An electronic musical instrument capable of producing a multi-system tone source effect which is an effect providing a musical tone with naturalness and resulting from simultaneous playing of a tone of a proper pitch and a tone of a pitch slightly different from the proper pitch. The inventive electronic musical instrument produces this effect with a smaller number of tone source devices than the number of systems.Composite musical tone waveshape amplitudes achieving the multi-system tone source effect can be represented by a single multiplication term of a sine waveshape function content corresponding to a certain pitch and a cosine waveshape function content corresponding to a pitch difference. According to the invention, the sine waveshape function content and the cosine waveshape function content are separately produced and these contents are multiplied with each other to produce the composite musical tone waveshape amplitudes.

Abstract: To provide a chorus effect in a digital musical instrument frequency separation between tones read out of two or more memories is effected by modifying the coded digital number which controls the rate of change of voice addresses in a memory by a predetermined value to produce a modified coded digital number, and then using said coded digital number and the modified coded digital number to read voices out of two or more memories.

Abstract: For use in an electronic musical instrument, such as an electronic organ, a first set of tone generators, preferably of the type where all of the notes of a musical scale are obtained by frequency division from a single frequency stable master oscillator, operates together with a second set of tone generators comprised of a plurality of individually tunable chorus oscillators for generating the notes of a musical scale in a frequency range where the sensitivity of the human ear to ensemble or chorus effect is appreciable. The chorus oscillators are individually adjusted to beat with and produce chorus effects with corresponding notes derived from the first set. In addition, the entire set of chorus oscillators is capable of being simultaneously and proportionally raised or lowered in pitch by applying a control voltage to a frequency control terminal.