Norlin Music, Inc.

Norlin Industries, Inc.

Peptek, Inc.

Norlin Music Company

Robert A Moog

William Pepper, Jr

Richard M Walborn

Roger Flavius Cox

Selected touch point locating apparatus has an array of two or more electrical touch members constituted by impedance elements coupled to a circuit for causing electric current to flow through a selected touch point as the algebraic sum of separate currents through the electrical touch members. The relative amplitudes are translated into at least two signals corresponding to the location in two axes of the selected touch point.

Arrays of resistive elements for use in touch panels and for producing

A plurality of a signal peak detection circuits connected in cascade for operation on a complex waveform input signal, for generating a reference signal having peaks occurring in time with the peaks of the fundamental frequency component of the input signal. The reference signal is processed for producing a voltage proportional to the period between successive signal peaks, which voltage is successively stored and monitored at select times for comparison of the relative magnitude changes in the voltage, for updating an output control voltage.

Frequency following circuit

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. The changes in the capacitance are converted to a DC voltage which is used to control the amplitude of an output signal.

Monophonic touch sensitive keyboard

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.

Compressor-expander for a musical instrument

A distortion sound effects circuit producing an output signal corresponding to an input signal but containing one of four selected types of distortion. A compressor which includes a voltage-controlled amplifier first compresses the audio input signal within preselected limits, and the distortion operations are performed on the compressed audio signal to advantageously render the subsequent distortion operations insensitive to gross amplitude fluctuations of the input signal. The compressor includes means for full-wave rectifying the compressed audio signal. The full-wave rectified signal is provided as a distorted output signal containing hard-even distortion of the type commonly achieved by severely, asymmetrically clipping a signal. A distortion circuit includes single voltage controlled square-low amplifier to which the compressed audio signal is applied performs the other three types of distortion. Soft-odd distortion is achieved by slightly and symmetrically overloading the input stage of the amplifier by an amount less than would result in clipping at the output stage. Hard-odd distortion is achieved by symmetrically and severely overloading the input of the amplifier to cause clipping at the output stage. Soft-even type distortion is achieved by squaring the compressed audio signal through modulation of the amplifier gain with the compressed audio signal while it is also applied to the amplifier signal input. A mixer having three inputs respectively coupled with potentiometers respectively fed by the amplifier output, the full-wave rectifier output and the undistorted, compressed audio signal output of the compressor circuit enables a musician to mix the three signals in any desired proportion.

Distortion sound effects circuit

An improved frequency sensitive circuit capable of adjusting one or more of its parameters in order to shunt an adjustable amount of electrical signal to a current sink, thereby controlling the amplitude of the signal. The frequency sensitive circuit is connected to the wiper of a potentiometer that is placed across the inputs of a difference amplifier in order to control the peak value of the cut or boost in the signal. The frequency sensitive circuit includes a shunt impedance connected between the wiper of the potentiometer and the current sink. A resonant circuit is connected to the impedance and is tuned to an adjustable resonant frequency. A compensation circuit, such as a difference amplifier referenced to the wiper, couples the output of the resonant circuit to the shunt impedance so that the impedance of the frequency sensitive circuit approaches infinity as the frequency of the electrical signal is displaced from the resonant frequency. As a result, the frequency sensitive circuit has substantially no effect on the overall amplitude of the electrical signal at frequencies widely displaced from the resonant frequency.

Parametric adjustment circuit

In an audio amplifier for amplifying signals from an electric guitar or the like having a conventional tone control circuit for selectively emphasizing input signals in the bass, middle and treble frequency ranges of the instrument, a multifilter circuit for emphasizing input signals with frequencies in selected, relatively narrow, frequency bands in the upper portion of the frequency spectrum to minimize aural fatigue. The multifilter circuit comprises a plurality of parallel connected, two-pole, resonant filter sections with different, relatively narrow, resonant frequency bands separated from one another by an amount on the order of 1/4 octave and forms a signal path that supplements the signal path provided by the conventional tone control circuit. The signals produced on the output of the tone control circuit are mixed with the multifilter output signals. Potentiometers are provided to vary the amplitude of the output signals of the entire multifilter circuit or selected ones of the filter sections thereof. Both the amplitude and phase frequency response of the multifilter are characterized by a plurality of successive peaks and dips, such that as the musician plays different notes, certain number of harmonics are emphasized in some notes, while other harmonics are emphasized in other notes with respect to amplitude while variations in the pitch or frequency of the input signal result in the phases of the individual harmonics to be rapidly shifted which causes minute shifts in the pitch of the individual harmonics produced on the output.

Amplifier with multifilter

A sound effect circuit with a phase shifter producing a signal shifted in phase with respect to an input signal, a combining circuit for arithmetically combining the input and phase shifted signals to produce an output signal, an oscillator for periodically modulating a characteristic frequency of the phase shifter and a modulation control circuit. The modulation control circuit causes the modulation rate to gradually increase when modulation is manually switched on and to gradually decrease when modulation is switched off. The modulation control also causes the characteristic frequency to vary inversely with the modulation rate. The system defined by a part of the circuit producing a first output signal proportional to the sum of the input and phase shifted signals has a comb shaped frequency response curve and a part of the circuit producing a second output signal proportional to the difference between the input and phase shifted signals has a comb shaped frequency response curve inversely related to that of the summing part of the circuit. When the two output signals are fed to separate speakers, the total frequency response curve of the two systems taken together is substantially flat, but the distribution of energy in the frequency spectrum moves in space as the modulation proceeds to produce a new 'stereo phase shift' sound effect. A rotary potentiometer for mixing the first and second outputs signals with each of the input signal and the phase shifted signal in selected proportion provides a third output signal with selectively variable characteristics.

Phase shifting sound effects circuit

An electronic music synthesizer is disclosed in which the sound producing chain includes a voltage-controlled oscillator, band-pass filter, low-pass filter, and amplifier in which selected control currents are supplied to low impedance points within the synthesizer circuit from a resistor matrix. The synthesizer produces sounds approximating different acoustic musical instruments or having different tonal qualities by the application of a predetermined voltage to one of fifteen input columns of the resistor matrix with selected other columns being grounded. The currents provided by the resistor matrix in combination with other externally generated currents control the center frequency and bandwidth of the band-pass filter, the cutoff frequency of the low-pass filter, the gain of the voltage-controlled amplifier, the time constants of transient contour currents used to control the filters and amplifier, and the waveform produced by the voltage-controlled oscillator. Specialized keyboard, waveshaping, contour generating and modulating circuits are also provided.

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East Aurora, NY, United States of America

Robert A Moog