Abstract: A string chorus generator in an electronic musical instrument that accepts a single audio input signal, applies it to three separate delay lines, and provides delay modulated outputs to be used in producing an ensemble musical effect resembling a group of strings in a string orchestra. Each of the three delay line channels is identical and comprises an analog shift register driven by a high frequency voltage-controlled oscillator along with appropriate filters and buffers. The frequency of the voltage-controlled oscillator of each channel is controlled by the filtered output of a microprocessor, thereby providing precise control over the modulation of each voltage-controlled oscillator. The modulating waveshape is generated by using a lookup table within a microprocessor and comprises a sine wave of 6.25 Hz superimposed on another, larger amplitude, sine wave of 0.78 Hz.

Abstract: Wrapped strings for musical instruments having a predetermined speaking length, wherein the wrapping wire is wound on the core wire to provide uniformly spaced helical convolutions spaced from each other by a distance at least as great as the diameter of the wrapping wire, the wrapping wire having a diameter smaller than the diameter of the core wire, said wrapped strings being so wrapped only within the speaking lengths of the strings.

Abstract: Means for adjusting the touch force required to depress the keys of a piano within the range normally preferred by pianists, comprising a plurality of spring member means having a relatively small spring constant (low stiffness). Each spring member means is connected at one of its ends to one of piano keys near the fulcrum thereof. Each spring member means is connected at its other end to a beam located above the keys and extending transversely thereof the full length of the keyboard. At least one of the connections of each spring member means is adjustable. The beam may be a single continuous member, or it may be made up of segments corresponding to groups of adjacent keys. In the initial adjustment each spring member means is typically prestressed by means of its adjustable connection to set the static touch force of its respective key to the desired value.

Abstract: A cymbal stand is taught comprising upper and lower tubular members in adjustable telescoping relationship. A pedal frame is affixed to the bottom end of the lower tubular member. The rearward end of a foot pedal is pivotally connected by a pair of arms to the pedal frame. The forward end of the foot pedal is pivotally attached directly to an actuating rod assembly extending upwardly through the pedal frame and the upper and lower tubular members. The pivotal attachments of the foot pedal arms to the pedal bracket and the forward end of the pedal to the rod assembly are coaxial, so that the pedal is swingable beneath the pedal frame between an operating position to one side of the pedal frame and a stowed position alongside the pedal frame and the lower tubular member on the other side of the pedal frame. The structure is provided with a set of pivotally attached legs terminating in footed free end.

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. Time division multiplex digital logic signals representative of the played keys are applied to a memory circuit and a comparator circuit. If the information stored in the memory from the previous scan cycle is unchanged the comparator provides an enabling signal to a monostable and enable logic circuit. A priority selector circuit provides logic information to the monostable and enable logic circuit which outputs this information and information representative of the total number of keys played.

Abstract: A developer device for electrostatic copiers includes a housing in which toner is circulated. The circulating toner is dropped in free fall at a predetermined location. Underneath that location are two side-by-side lengthwise extending channels into which the falling toner is substantially uniformly distributed. Guide baffles in one channel direct the incoming toner along the channel in one direction, and guide baffles in the other channel direct toner in the opposite direction.

Abstract: The present invention provides a system in an electronic musical instrument for measuring the setting of a variable resistor for controlling tempo, displaying the tempo to which the setting corresponds, and controlling the tempo so that notes are sounded in accordance with the setting measured and displayed. The tempo control comprises a tempo potentiometer that is self-calibrating by means of a microprocessor which automatically measures the resistance of both the current setting of the tempo potentiometer and the maximum setting of the potentiometer so as to maintain the desired correspondence between the mechanical position of the tempo potentiometer and the tempo selected. A non-linear relationship is introduced between the mechanical position of the tempo potentiometer and the tempo selected in order to maintain a desirable correspondence between the mechanical position of the tempo potentiometer and the tempo selected.

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 microprocessor controlled electronic capture combination action system for use in an electronic organ for selecting a predetermined combination of stops to define the organ voicing. The system includes a plurality of stop tabs for setting and resetting the stops, a plurality of pistons for setting a desired combination of stops to a predetermined condition, a random access memory for storing data associated with a selected combination of stops, a read only memory containing a permanently stored operating program incorporating a plurality of operating instructions, an indicator light associated with each of the stop tabs and a microprocessor responsive to the operating instructions. The stop tab and pistons are continually and sequentially scanned to detect the contact closures. Actuated stop tabs cause the associated stops to be selected and the indicator lights illuminated.

Abstract: Electronic and logic circuitry for an automatic tonal bass rhythm accompaniment feature and an automatic chord feature in an electronic organ. Automatic bass rhythm accompaniment produces a pattern of notes based upon a tonic note selected by the instrumentalist such that the desired musical effect is produced when the pattern of notes is combined with the notes being played by the instrumentalist. The electronic organ has stored in a memory various rhythm patterns which can be selected by the instrumentalist by closing rhythm switches. Electronic circuitry then causes notes for the selected rhythm pattern or patterns to be played automatically in response to the actuation of a pedal switch or keyswitch. The automatic chord feature of the present invention provides selectively major triad and dominant seventh chords or minor triad and diminished seventh chords automatically in response to the selection of a root note by the instrumentalist.

Abstract: A spur and stabilizer assembly for a bass drum. The assembly comprises a pair of tubular stabilizer elements with their upper ends mounted substantially adjacent each other to the inside surface of the bass drum shell. The tubular stabilizer elements extend downwardly, laterally and forwardly with respect to and within the bass drum shell. A pair of spur brackets are affixed to the outside of the shell and have portions extending through perforations in the shell. The lower end of each of the tubular stabilizer elements is operatively and adjustably connected to the adjacent one of the spur brackets. A pair of spurs is provided. Each of the spur brackets has a bore therethrough, coaxial with its respective tubular stabilizer element. Each spur is telescopically received in one of the spur bracket bores and the connected one of the tubular stabilizing elements. A set screw is mounted in each spur bracket to retain the spur therein in adjusted axial position.

Abstract: An arpeggio system, utilizing bipolar digital logic devices in all control and sequencing functions, generates a variety of arpeggio and strum note patterns. A key operated switch enables a NOR logic note gate, or a series of octavely related note gates, and activates a system clock which causes a pulse to be transmitted along a chain of shift registers, one of which corresponds to each note of the organ. If a given note gate has been enabled when its corresponding shift register is pulsed, the note gate is triggered. When a note gate is triggered, the system clock pauses for a preselected interval allowing the signal from a corresponding tone generator to be sounded through an appropriate system of filters and amplifiers. The system clock can cause the shift registers to scan in the up, down, or up and then down directions. An octave priming device can permit the sounding of notes in higher octaves which correspond to notes actually played.

Abstract: A stop tab mechanism for an particularly electronic organ of the type having a capture combination system. The stop tab mechanism includes an elongated stop tab having a front portion, a central portion, and a rear portion, a mounting bracket for the stop tab, spaced apart front and rear rests secured to the mounting bracket, guide means mounting the central portion of the stop tab for pivotal movement relative to the rests, including a spring urging the central portion of the stop tab into contact with the front and rear rests, and switch means operatively connected to the rear portion of the stop tab.

Abstract: An electronic musical instrument using continuous tone generators capable of simulating the sounds of a conventional acoustical piano. The instrument includes a gating circuit featuring a timed switch travel circuit having a double-time constant for improved control of the dynamic range from the keyboard, and a soft pedal controlling the keying voltage to produce more realistic emulation of the dynamic effects of an acoustical piano. The gating circuit produces a double-time-constant envelope of nearly harmonically related signals for a more realistic piano timbre. The tone spectrum is also controlled as a function of signal level by means of a resistor matrix feeding selected inputs of an active ladder filter, in order to reproduce timbre variation with dynamic level.