Yamaha Corporation

Nippon Gakki Seizo Kabushiki Kaisha

Rokurota Mantani

Takashi Tamaki

Shinya Koseki

Nobuo Sugiyama

Yasutoshi Kaneko

Hanzo Taguchi

Masatosi Murayama

Toshihiro Nishino

A grand piano generates acoustic tones through vibrations of strings and sound board so that the acoustic tones are converted to analog audio signals at recording points over the sound board, and a group of waveform data sets are produced from the analog audio signal through sampling and analog-to-digital conversion; when electronic tones are generated, delay parameters and volume parameters are determined on the basis of differences between the recording points and tone radiating points occupied by loud speakers, the sets of waveform data series are sequentially read out from the group of waveform data sets and are modified with the delay parameters and volume parameters so that the electronic tones become close to the acoustic tones.

Method for making electronic tones close to acoustic tones, recording system for the acoustic tones, tone generating system for the electronic tones

A servo-controlling system incorporated in an automatic player piano selects detecting signals each indicative of actual status of a key or a pedal to be manipulated from all of the detecting signals, and sequentially fetches the selected detecting signals in a time sharing fashion for comparing the selected detecting signals with reference signals each indicative of target status of the key or the pedal, thereby promptly controlling actuators associated with the keys and pedals to be manipulated without complex wiring network.

Servo-controlling system incorporated in keyboard instrument for

A circuit is provided for detecting abnormal conduction of current conducted through a solenoid in response to the pulse width modulation signal. The circuit includes a measuring means, for detecting conduction current conducted through the solenoid in response to the pulse width modulation signal and measuring continuous conduction time of the conduction current, and determining means, for determining a conduction to be an abnormal conduction when the continuous conduction time is longer than a predetermined time. Thus, the circuit can be miniaturized and the accuracy of the circuit is not affected by the accuracy of its components. And, the circuit is capable of detecting the half short state of the transistor driving the solenoid and not malfunctioning even if tile power is turned off.

Circuit for a detecting state of conduction of current through a solenoid

A photosensor controller is described comprising sensor units 17-0 to 17-7, 18-0 to 18-7, 19-0 to 19-7 and a circuit 16 driving light emitting diodes by a method of time division. Each sensor unit comprises pairs of an LED and a photodiode. After the driving circuit 16 turn on the proceeding LED, if turns off the next LED for a period corresponding to the delay time constant of a detected signal from a photodiode which corresponds to 'OFF', making a completely to '0' in this off period of turning off, even in case of waveform rounding. Following this, the next LED is turned on.

Photosensor controller for musical instrument having a driving means for

An acoustic keyboard musical instrument such as a piano includes a keyboard, a mechanical musical tone generating mechanism, a fallboard, and an operation panel for an external electronic musical tone generating unit. The keyboard includes a plurality of keys aligned on a musical instrument body. The fallboard is pivotally supported by the musical instrument body and to be closed/opened so as to cover/uncover the keyboard. The musical tone generating unit electrically generates a musical tone signal in response to a key depression on the keyboard under the control of control information which is provided by switches on the operation panel. The operation panel is located at a position opposite to a performer in the inner surface of the fallboard when the fallboard is open so that the performer can operate the operation panel during his performance at the keyboard.

Acoustic keyboard musical instrument

An octave conversion system of the fundamental frequency of an audible tone signal produced by electrically picking up mechanical vibration of a musical instrument in which the audible tone signal and an audible modulation signal having a frequency in a preselected relation to the fundamental frequency of the tone signal are applied to a multiplier which is preferably constituted by a voltage-controlled amplifier. When the modulation signal has a frequency half that of the tone signal, the tone signal is one-octave down-converted, while, when the modulation frequency is equal to the tone signal frequency the tone signal is one-octave up-converted. With this frequency conversion system the fundamental wave component of the octave-converted tone signal has the same envelope as that of the original tone signal. This frequency conversion system is advantageous in attaining small size versions of electric musical instruments and extension of inherent compasses of electric musical instruments.

Frequency conversion system of tone signal produced by electrically

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.

Electronic musical instrument system having independent tone cabinet

A waveform converter for an electronic musical instrument wherein an input rectangular wave tone signal is supplied to a frequency-voltage converter to generate a D.C. voltage control signal having a voltage level corresponding to the frequency of the input rectangular wave tone signal; and a one-shot multivibrator is triggered by the input rectangular wave tone signal to produce an output rectangular wave tone signal having the same frequency as the input rectangular wave tone signal. The one-shot multivibrator comprises duty factor control means responsive to the D.C. control voltage signal for determining the duty factor of the output rectangular wave tone signal.

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Hamamatsu, Japan

Rokurota Mantani