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: An electronic musical instrument incorporates one or more pressure sensitive push-button controllers actuable independent of the keys or other note selecting elements of the instrument to vary a corresponding number of musical parameters. The specific controllers provide a sensitive, smooth, repeatable parameter variation in response to both the location and the force of the player's touch.

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: 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: An inexpensive single bus keyboard circuit for voltage controlled electronic musical instruments. The keyboard signal voltage is sampled and stored after each depression of a key, or release of a key when other keys are held in a depressed state, and a gate detector is provided to prevent sampling and change of stored voltage when all keys are released, to thereby insure that the last stored signal voltage is retained when all keys are released. A program counter establishes the timing relationships between the generated control signals and provides adaptive timing to prevent response to spurious key switch signals. The circuit distinguishes in a simple manner between keyboard sample voltages corresponding to the depression of one or more keys and those corresponding to the condition in which no keys are depressed.

Abstract: A touch sensitive device is associated with at least one key of an electronic musical instrument such as an electronic organ, includes a layer of a pressure responsive, variable conductance material, and exhibits a switching action when subjected to pressure beyond a threshold pressure, any increase in pressure thereafter providing an increase in conductance up to a saturation pressure. The device may be used either as a combined switch and amplitude control or may be used in associated with one or more capacitors to provide either a high pass or low pass touch-control audio filter. In a totally polyphonic instrument a tone generator and touch-control filter are respectively associated with and responsive to each key depression, the output signal from each activated filter being coupled preferably to audio mixer circuitry.

Abstract: A low noise resonant filter of wide dynamic range and low distortion is formed from a number of series-connected filter stages, each comprising a current integrating amplifier driven from transconductance formed from a bipolar differential pair with feedback to one member of the transconductance pair to maintain its transconductance substantially constant. A further bipolar differential pair transconductance at the input stage operates with a widely variable transconductance and provides soft limiting and wide dynamic range, especially when the filter is operated in the resonant mode.

Abstract: The keyboard type instrument includes circuitry for controlling an envelope generator and a voltage controlled oscillator which in sequence operates a voltage controlled filter, and a voltage controlled amplifier both of which receive control signals from the envelope generator. The keys of the keyboard preferably have a common variable conductance touch sensor or transducer associated therewith which is responsive to key depression pressure in excess of a predetermined threshold pressure to control one or more audible characteristics of the played note. In one embodiment vibrato, pitchbend, brilliance and volume of the note are controllable. Associated with the keyboard is selection means including a plurality of audible characteristic selectors and variable means delimiting the range of the audible characteristics.

Abstract: The system of this invention is for use with an electronic musical instrument having a keyboard, and generally includes keyboard circuitry, audio waveform generators, envelope generators, static and dynamic filter circuitry and power amplifier and speaker apparatus. In accordance with one feature of this invention, the system comprises means for establishing different digital voice codes which are coupled to read only memories associated with the audio waveform generators, envelope generators and main voice circuitry. This voice code provides a limited number of program conditions to control such variables as audio waveform pulse widths, envelope attack, decay, sustain or release intervals, and instrument resonator control. Another feature of the present invention is concerned with the keyboard circuitry which operates from a digital key and octave code. Each code is sequentially interrrogated to determine if the corresponding key has been played.