Abstract: A piano action keyboard for an electronic musical instrument or the like wipes a switch actuator (or other mechanical component of electric signal translation means) across switch contacts on a printed circuit board to generate signals indicative of the position and motionof a key when played. The keyboard provides a highly realistic piano "feel" through an array of paired depressable playing keys and arms. Each such arm supports a switch actuator or the like, with varying force transmission at different stages of depression of its corresponding key, the overall electrical-mechanical combination affording a response in terms of both actual results and kinesthetic feedback simulating a manual piano action.

Abstract: In a musical instrument having one or more tone generators in which a plurality of data words are transferred sequentially from note registers in repetitive cycles at rates proportional to the pitches of tones being generated, apparatus is provided for varying the spectral content of tones having both harmonic and nonharmonic overtones. Control signals are used to vary the amplitudes of the overtones. An independent formant control signal causes the tones to have a time variant spectral quality.

Abstract: Apparatus for producing signals of varying volume and pitch which are functions of the magnitude and distribution respectively, of weight (or weights) placed upon a platform hinged at one corner and swingable in mutually orthogonal directions. Sensors convert the physical displacements occurring at first and second corners opposite of the platform adjacent to the hinged corner into signals for controlling the volume and pitch of an output signal. Alternatively, displacement of the platform may be controlled by the application of varying pressure by means other than full body weight, such as the operator's finger(s).The apparatus may be utilized as a unique means for producing music or musical sounds responsive to a person dancing or otherwise moving upon the platform to provide an entertainment form which is both unusual and enjoyable.

Abstract: This is an electronic organ drawbar circuit in which selection of the footage volumes is accomplished by means of a switch matrix; and sets of footage/volume correlations so chosen are stored in a memory. Another group of switches is used to select among several different memory fields, so that various sets of footage/volume data can be stored while another set of data is in use, and each stored set can be recalled for subsequent re-use.

Abstract: An electronic musical instrument of a type capable of producing a musical tone corresponding to the tone pitch of a depressed key by controlling oscillation frequency of a voltage-controlled type oscillator by a pitch voltage corresponding to the tone pitch, wherein musical tone elements such as tone pitch and tone color are controlled in accordance with a control voltage which is produced for each individual key but is different from the pitch voltage.A temperature curve can be determined by controlling the tone pitch of the musical tone by this control voltage as well as by the pitch voltage. A desired temperament curve can be obtained by suitably adjusting the values of the control voltage for the respective keys. The tone color control is effected by varying the cut-off frequency of the voltage-controlled type filter in accordance with the aforementioned control voltage.

Abstract: A piano-action keyboard for an electronic musical instrument or the like wipes a switch actuator (or other mechanical component of electric signal translation means) across switch contacts on a printed circuit board to generate signals indicative of the position and motion of a key when played. The keyboard provides a highly realistic piano "feel" through an array of paired depressable playing keys and arms. Each such arm supports a switch actuator or the like, with varying force transmission at different stages of depression of its corresponding key, the overall electrical-mechanical combination affording a response in terms of both actual results and kinesthetic feedback simulating a manual piano action.

Abstract: In a musical keyboard instrument of a type having a number of tone generators substantially less than the number of keys, one of the tone generators being assigned to a key when activated, the pitch of the tone generator being set by the particular key, apparatus is provided for maintaining a constant audible loudness level to the listener from the tone generator regardless of the pitch of the tone generator. A plurality of sets of amplitude values are stored in a memory, each set including one value for each key. Each set of values corresponds to a particular loudness level. The envelope amplitude of the tone generator output is controlled to produce the same loudness level for all notes by addressing a set of values according to the selected loudness level and addressing a particular value according to which key is activated. An amplitude value is selected which is then used to control the envelope amplitude of the tone generator output signal.

Abstract: The electronic musical instrument is provided with a plurality of musical tone generating channels of a number smaller than that of the keys and a channel processor for randomly assigning key information representing depressed keys to the musical tone generating channels. Furthermore the musical elements including the pitch, the tone color and the envelope of the musical tones generated by respective channels are made to be different thereby imparting a random property (casualness) to the generated musical tone.

Abstract: A keyboard for a monophonic musical instrument has a plurality of touch sensitive keys which function as variable capacitors, the capacitance depending on the force applied to the keys. The variable capacitance is detected and used to produce a variable control voltage which is used to execute one or several of various control functions, such as controlling the volume of the sound produced by The instrument, controlling the cutoff frequency of a low pass filter in the output system of the instrument, controlling the amount of vibrato or other periodic modulation introduced into the sounds produced by the instrument, controlling the frequency of the vibrato or other periodic modulation, or controlling the amount of "bend" in the pitch of a sound produced by the instrument, i.e. shifting the pitch slightly from its nominal value. The variable capacitors employ a conductive elastomer which is deformed in response to the force applied to the keys.

Abstract: Pedal control circuits for use with an electronic musical instrument, such as a piano, which provide control functions analogous to the actions of a sustaining pedal, of a sostenuto pedal, and of a volume pedal of a conventional piano. Damper circuits operable in conjunction with a sustaining pedal provide an effect analogous to the action of the sustaining pedal in a conventional piano, a latching circuit actuated by depression of a sostenuto pedal operates in conjunction with the damper circuits in a manner analogous to the action of a sostenuto pedal in a conventional piano, and a volume pedal and associated circuitry is operative to determine the level of the output tones only at the moment of strike of the keys, an action analogous to that of the volume pedal in a conventional piano.

Abstract: A binary interpolator circuit is embodied in an electronic musical instrument for producing a relatively smooth, inaudible transition between steps of different amplitude in a stepwise advancing or decreasing waveform, such as an envelope signal for a note from a percussive type instrument or voice such as a piano. The binary interpolator circuit includes a counter circuit for producing a sequence of stepwise changing binary coded signals and a combining circuit for combining the interpolating signals, in the sequence produced, with a binary coded scaling signal corresponding to the amplitude difference between the two points in the stepwise changing waveform between which interpolation is desired. A comparator circuit compares the interpolating signals, in the sequence produced, with the scaling signal and produces an output control signal for indicating whether the binary coded numbers corresponding to the respective interpolating and scaling signal are equal.

Abstract: The device of the invention extracts a fundamental frequency from signals coming from a played musical instrument. From this is synthesized a waveform with the same fundamental frequency which can be given an arbitrary form, so that an audical impression of e.g. a violin, a trumpet or a guitar can be given to sound produced by the waveform. The waveform is produced by making a pulse train with frequency n times the fumdamental frequency, leading the pulse train to a counter activating cyclically and sequentially n different outputs. The outputs are summed with different and adjustable weights, and the waveform is determined by adjusting the n weights. The number n can be any number. An embodiment is shown with n=16.

Abstract: Electrical circuitry for varying the relative distinctiveness between the lead and rhythm audio signals produced by an electrical guitar, or the like, according to the strength with which the musician picks the guitar strings. The rhythm signal is compressed in response to how hard the player strums or picks the guitar, while the lead signal is expanded as a direct function of rhythm signal compression. An electrical signal is generated from the rhythm signal for controlling the extent of compression and expansion of the audio signals.

Abstract: The present invention is an electronic musical instrument the type in which information of the actuation of keys is detected by scanning the keys of a keyboard. The electronic musical instrument includes keys selectively actuable for producing sounds which correspond to respective musical scale notes, circuitry for sequentially scanning these keys for detection of the information of the actuation of these keys, and a memory circuit corresponding to each of the keys so that the information of the actuation of the keys is stored in the memory circuits.

Abstract: Linearly binary-coded digital control signals representing specific time segments of musical sounds are used in part to control stepped ramp signal generators in a digital synthesizer which runs continuously on a fixed program. The ramp signals are used to control amplitude and frequency parameters of multiple digital oscillators that produce respective constituent tones of the musical sound segments. The synthesizer is operable in response to time-multiplexed digital control signals for multiple musical voices, one voice portion of which is also being computed in real time for multiplexing with previously computed and stored digital control signals for other voices. The indicated computations are effected by known techniques on a commercially available computer to translate performer-actuated transducer output signals, designating notes of a composition, into the aforementioned binary-coded digital control signals.

Abstract: In a digital touch response circuit or touch signal processing circuit for producing a control waveform signal to control a musical tone to be produced in response to a player's finger touch on a key, digital touch data representing a player's instantaneous finger touch on a key is compared in a comparison circuit with digital output data from an operation circuit such as an adder circuit, which varies at a rate as the result of addition of a rate value to input data applied to the adder. A selection circuit is responsive to the comparison circuit to selectively couple the output data of the adder and the digital touch data to a temporary memory circuit such as shift registers. The output data from the memory circuit is coupled to the adder as the input data thereto.

Abstract: An echo effect in a polyphonic digital tone synthesizer in which a musical tone is repeated at a controlled repetitive rate but decreasing peak amplitude when a key is depressed. The tone is repeated until the peak amplitude decays to a predetermined level regardless of when the key is released. If the key remains depressed, the peak amplitude decay recycles so that an echo effect will be repeated. The echo effect is obtained on a plurality of overlapping notes that need not be keyed in unison. The echo control includes an echo envelope register which stores a control word for each key that is depressed. The control word includes bits coded to identify the current amplitude of the echo decay envelope. The value of the control word is decremented at a control rate to provide a decaying echo amplitude. An echo delay register stores a control word for each key depressed, the control word being incremented at a controlled rate.

Abstract: An electronic organ in which a manually adjustable potentiometer varies the control voltage supplied to a voltage controlled amplifier interposed between a source of tone signals and an organ output circuit with the potentiometer being connected to the amplifier by a circuit which eliminates scratching and discontinuity in the potentiometer output. The amplifier can be bypassed by circuitry for supplying lower frequency bass signals to the amplifier output under conditions of high attenuation of the incoming signal in the amplifier.

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: The disclosure describes improved apparatus for synthesizing an audible note from its volume, attack-decay envelope and waveshape characteristics. By employing multiplying analog-to-digital converters, the characteristics can be rapidly generated and combined in real time, thereby enabling the use of the synthesis in performing instruments.

Abstract: In an electronic musical instrument comprising a keyboard including a plurality of keys, a frequency information memory device for storing frequency informations corresponding to respective keys, a plurality of musical tone forming means including a waveshape memory device for forming musical tones in response to the output of the frequency information memory device, and a shift circuit interposed between the frequency information memory device and the musical tone forming means for effecting a footage change of an octave unit, there is provided a preset circuit for applying a plurality of preset footage signals to the shift circuit and for applying another preset signals which are necessary to form musical tones to the musical tone forming means.

Abstract: There is disclosed a system for encoding of bass and treble expression effects while recording from the keyboard of an electronic player piano wherein the intensity of the music being recorded is reflected in variations in the power of the acoustic waveform produced thereby. The key note or key switch actuations are multiplexed in a serial bit stream of data and stored in a shift register and then separately combined with the bass and treble expression data bits in a format which, upon re-creation of the original musical presentation, results in a more faithful rendition of the original performance.

Abstract: A system for the selection and phase control of humbucking coils in electromagnetic guitar pickups to permit the musician to easily select different sounds using digital memory means for storing different combinations of gate control bits to select the pickup coils to be used, the phase of the coils selected and the output level of the selected coils combined. A three-way switch is used to count up, count down or hold a memory address for selection of a combination. The address is displayed for verification. Memories may be prestored ROMs, or alterable RAMs in which write enable control is controlled by a three-way switch. Three address counters may be provided to permit the musician to quickly select from three predetermined combinations through operation of a three-way switch.

Abstract: There is disclosed a method and apparatus for encoding of expression while recording from the keyboard of an electronic player piano wherein the intensity of the music being recorded is reflected in variations in the power of the acoustic waveform produced thereby. There is a delay between the time the key is struck and the time that the note is sounded or heard by the listener. The apparatus measures the changes in power by performing a digital integration of a waveform. The key note or key switch actuations are multiplexed and a serial bit stream of data and stored in a shift register and then combined with the expression data bits to form the data stream which is encoded in a bi-phase encoder to be recorded on tape.

Abstract: An envelope waveform generating apparatus comprising a key code generating device composed of a means for releasing key code data and a means for outputting first and second control signals, a key assignor composed of a means for outputting a third control signal, a level setting means, and a function generator. The envelope waveform generating circuit is provided with a touch response so that the level of envelope waveform may readily be set.

Abstract: A sustained repeat control in a digital polyphonic synthesizer for gradually decreasing the amplitude of one or more notes generated repetitively in response to operation of a single key. The sustained repeat control includes a digital register storing a plurality of control words in digitally coded form, there being one control word assigned to each note being generated at any one time. Each word includes bits coded to indicate the current relative amplitude of the associated note. When a key is depressd, the control word or words for the note or notes assigned to that key have bits initialized to a predetermined value. When the key is released the amplitude values represented by the bits are counted down periodically. The bits in turn control the amplitude of the repetitively generated notes, a zero detector terminating the operation when the bits are decremented to zero.

Abstract: An amplitude curve generator for use with an electronic organ or the like to control the musical shape of an audible tone. The generator utilizes a simple binary down counter driven from a clock source to produce a sequence of decreasing binary numbers that approximate the relative amplitudes of equally spaced points along an exponential decay curve. The count condition of the least significant bits of the counter correspond to the mantissa of number expressed in binary floating point notation. The most significant bits represent the power. The bits of the mantissa are transferred to a parallel shift circuit and shifted a number of times determined by the bits of the power to convert the number in the counter to fixed point notation. The output of the shift circuit is used to control the envelope amplitude of a musical tone. The output may be subtracted from one (2's complement) to produce a set of values that correspond to an exponential attack curve rather than a decay curve.

Abstract: A plurality of tone signals corresponding to one note and having the same fundamental frequency and different harmonic components are modified in amplitude according to the shape of an envelope signal generated upon key depression and having an amplitude proportional to the key depression speed. One of the amplitude-modified tone signals is clipped at a predetermined level and then mixed with another amplitude-modified tone signal. The frequency spectrum of the resultant tone signal varies with time like a piano.

Abstract: Spatially separated high frequency tonal effects from an electronic musical instrument having less tone generators than keys selectable. A high frequency speaker system is provided in addition to the normal audio system. The audio signals produced by the tone generator are applied to a high pass filter-amplifier circuit before application to a tweeter switch. Digital logic is provided to demultiplex the note generator capture signal for note generator assignment information. The demultiplexer information is applied to the tweeter switches to effect the activation of a tweeter switch and permit the sounding of the tweeter speaker. Thus it may be seen that the present invention permits the separate soundings of the high frequency range in a directional fashion, creating the movement of sound sources and changing spatial relationships in response to key activity.

Abstract: There is disclosed an expression system for playback of a magnetic tape record rendition of a musical presentation. The detected intensity level for the bass and treble halves of the keyboard are assigned different data bit positions in the frames of recorded data bits of a time division multiplexed record system. The binary bits are weighted and used to modulate the width of pulses supplied to selected solenoids which actuate the striker-hammer members of the instrument so that the average drive energy applied to the solenoid is proportional to the desired intensity thereby more faithfully reproducing the manual action of the original performer.

Abstract: A keyboard operated polyphonic tone synthesizer which is touch responsive to the force applied to the keyboard mechanism. Operation of a key operates through a pneumatic transducer to provide an air stream having a velocity proportional to the force applied to the key. A transducer responsive to the velocity of the gas produces an output pulse having a peak amplitude proportional to the peak velocity of the air. This voltage in turn is used to control the peak amplitude of a musical tone generated in response to the operation of the key so that a direct relation exists between the force with which the key is operated and the amplitude of the resulting sound generated by the instrument.

Abstract: A frequency generator for a keyboard operated electronic music instrument using a single master clock source for selectively producing all the notes of the musical scale. A set of frequency numbers corresponding to each of the notes of a diatonic scale are stored in a memory. A frequency number is selected from the stored numbers according to the note to be generated when a key on a keyboard is activated, the selected number being applied to an adder-accumulator periodically at the master clock rate for incrementing the contents of the accumulator. Overflow pulses from the adder-accumulator shift amplitude values sequentially from a set of values stored in a shift register through an adder to a digital-to-analog converter. The adder modifies the amplitude values by applying a fractional part of the incremental difference between each value and the next value in the sequence to the adder. The fractional amount is determined by the content of the adder-accumulator and changes with each master clock pulse.

Abstract: In an electronic musical instrument a key touch signal is generated in response to the operation of a key, and a plurality of control signals having different waveforms are produced from the key touch signal.Different control signals are used for independently controlling at least two of a plurality of musical tone elements that determine the tone pitch, color and volume of the musical tone generated by the musical instrument.

Abstract: A volume control arrangement for an electro-acoustic system, said arranget having an adjustable amplification factor and a frequency characteristic dependent thereon, and comprising a frequency selective circuit which has an amplitude/frequency characteristic curve having at least one maximum lying within the audio frequency range and equivalent to the pass range of a band filter, and a circuit arrangement for varying the frequency and amplitude of the maximum in dependence on the adjustment of the amplification factor.

Abstract: In an electronic musical instrument of the type having keys, a system for controlling the volume of the sound produced by the instrument when the keys are depressed or struck. For each key, the system comprises a tone generator, a gate coupled between the tone generator and the speaker of the instrument; and control means for producing a control signal having an amplitude which is a function of the speed at which its associated key is moved while being depressed. The control signal is applied to the gate to pass the output of the tone generator to the speaker and to control the volume of the sound produced by the speaker.

Abstract: An electronic musical instrument providing continuous cybernetic tone finding controlled by functions of the human mouth. The instrument includes a mouthpiece into which air is to be blown from the mouth of a player having a measuring apparatus at least partially mounted therein. The measuring apparatus includes an arrangement for producing a pitch determining signal representing a measure of the mouth cavity of the player and a volume determining signal representing the velocity or pressure of the air blown into the mouthpiece. Tone generating apparatus is provided for generating a tone signal whose frequency varies with the level of a control signal applied thereto with a control signal being applied to the tone generating apparatus in accordance with the pitch determining signal and having a level representing a measure of the mouth cavity of the player.

Abstract: A multiband speaker system means includes a high frequency section normally balanced with one or more lower freqency sections. A thermistor is serially associated only with the high frequency section whereby, for certain high power signal combinations, a lesser proportionate increase in output occurs in the high frequency section than the low frequency section. This not only makes possible a lower power rating, but also eliminates certain effects that are not musically desirable.

Abstract: A device for encoding the expression of a keyboard percussive instrument is disclosed. The apparatus places a suitable AC voltage on a coating applied to a hammer and positions a pair of capacitive coupled pads near the string to be struck by the hammer. As the hammer sweeps past the pads, signals are capacitively coupled from the hammer motion to the pads. Suitable latches are set and unset to form a signal which is coupled through a switch, a sample and hold amplifier, then to an analog to digital convertor which forms an expressive signal of N bits length. The signal is begun by depression of the key and is terminated by closure of the key upon release by the musician, the key of the instrument being provided with capacitive pickup pads coupled to the key and through a reset gate to the latches. Alternate embodiments are additionally disclosed.

Abstract: An instrument for producing musical sounds which includes a keyboard, means connected with the keyboard for producing a plurality of musical sounds and means shifting said keyboard in one or more of a plurality of linear and rotational directions to vary such parameters as pitch, loudness, and tone.

Abstract: A volume controller for an electric musical instrument of portable type, in which an audio-signal transmission circuit is provided in the signal path of the electric musical instrument. The audio-signal transmission circuit includes a variable circuit element. A pendulum is provided in a casing of the electric musical instrument so as to be swung about a supporting shaft. The value of the variable circuit element is controlled in accordance with the swing of the pendulum to vary the sound volume of the electric musical instrument. A level may be provided on the casing to indicate the controlled condition of the pendulum. A stopper may be provided to tempororily stop the swing of the pendulum.

Abstract: A tone-generating system for an electronic musical instrument of the percussion type is provided wherein an audible tone closely approximating the corresponding tone of a conventional instrument is generated electronically. A single-pole, double-throw switch is actuated by a key to initiate generation of the tone and a tri-level detecting circuit coupled to the switch is utilized to determine which of the three states the switch is in; that is, the two "throws" or positions of the switch which correspond to the released and depressed positions of the key, and the state in which the switch is between the other two positions. By detecting the three states and developing corresponding control signals, counting circuitry may be utilized to determine the intensity with which the key is depressed to enable generation by a read-only memory of digital scaling signals representative of the variations in amplitude of the initiated tone with respect to the intensity with which the key is depressed.

Abstract: A piano having a sound-enhancing system incorporating transducers, amplifiers and loud speakers, all incorporated into or upon the piano.

Abstract: An electronic synthesizer instrument incorporates bass pedals for the notes of the musical scale, together with foot control apparatus adapted to select and modify the tone quality of sounds produced by operation of the bass pedals. The foot control apparatus includes push button switches which are operated by the toe of an operator's foot, and slide controls which are positioned by the operator's foot. At least some of the switches are preset switches for selecting and controlling multiple combinations of the functional units of the synthesizer. The control state of the instrument is at all times indicated by readily observable indicating lights.

Abstract: A musical instrument having a general body outline similar to that of a saxaphone. A front key panel having a plurality of keys mounted thereon is located for easy fingering access to the keys which are in the same general location as the fingering keys on a saxaphone. A rear control panel is provided for mounting instrument voice characteristic and special effects controls. A mouthpiece is provided for engagement by a player's mouth and a pressure transducer is carried in the mouthpiece for communication with the player's breath pressure and for producing a pressure signal corresponding thereto. The pressure signal is connected to a pressure attack circuit for producing a pressure attack signal. Finger pressure applied to predetermined combinations of keys provides predetermined combinations of key pulses for connection to a key decoder. The key decoder produces a binary output corresponding to the predetermined combinations of key pulses which ranges from zero to 1111.

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: A keyboard of an electronic musical instrument incorporates a plurality of variable capacitors, one for each key, with one conductor of each capacitor being connected for movement with an individual key of the keyboard toward and away from the other conductor, so as to vary the capacitance of the capacitor in accordance with the force with which the key is depressed.

Abstract: A musical instrument includes a multiplicity of circular endless magnetizable tapes with a plurality of different tracks, a multiplicity of pick-up heads for each of the tracks and a multiplicity of variable-gain amplifiers connected to the tracks, respectively. Keys having respective contact means for energizing each of the amplifiers, cause a multiplicity of magnetic elements to generate respective voltages in coils, each voltage being proportional to the force with which an individual key has been depressed. This voltage sets the gain of a respective amplifier, so that the loudness of a recorded tone heard is proportional to the actuating force of a key.

Abstract: This invention provides an electronic musical instrument capable of producing plural musical tones simultaneously and also capable of controlling the pitch, tone color and volume of the musical tones in response to a player's finger touch on a key.Transducers capable of electrically detecting the finger touch, i.e. factors including pressure and speed of depression and displacement of the key, are provided for respective keys. Analog outputs of these transducers are sampled and multiplexed in time sharing by each of channels of the number equal to a maximum number of musical tones to be produced simultaneously, and each of the multiplexed signals is held in a corresponding one of condensers provided in the respective channels. The pitch, tone color and volume are controlled in accordance with the magnitudes of voltages held in these condensers. Suitable discharging circuits are connected to these holding condensers.

Abstract: A rotary potentiometer is actuated by a pedal movement converted to rotary motion by a cable-sheave arrangement in which the sheave has a varying radius to its peripheral surface. The sheave is preferably mounted on the potentiometer shaft in an angular relationship that causes a minimum rotation of the shaft for a given pedal movement at a minimum resistance condition of the potentiometer.

Abstract: A music synthesizer produces pitch-proportional voltages in a novel resistor network, uses these voltage via keyboard control to generate in a voltage-controlled oscillator a high frequency signal, being a multiple of all the harmonic frequencies desired, separates the individual harmonics, converts them to sine waves with voltage-controlled tunable tracking filters, blends the waves in desired proportions, introduces transients of attack, decay, sustain, and release of key into each note, and introduces appropriate vibrato. An alternate apparatus accepts an external signal and converts it to voltages proportional to frequency, whereby accompaniment on pitch, in "close harmony" or more distantly related, is provided.