Other

Yamaha Corporation

Wayne L Stahnke

Yuji Fujiwara

Rei Furukawa

Takashi Tamaki

Taro Kawabata

A piano is equipped with an actuator that moves the piano pedal mechanism in a manner that reproduces the pedaling effects of an original performance with high accuracy. The actuator comprises a solenoid, a permanent magnet, a velocity sense coil, and a Hall-effect sensor. The Hall-effect sensor provides an indication of the displacement of the solenoid plunger in accordance with an inverse-square law. Closed-loop feedback control is provided to effect a very true reproduction of pedaling effects. Automatic calibration allows for simple installation.

Pedal actuator with nonlinear sensor

A piano is equipped with an actuator that moves the piano pedal mechanism in a mariner that reproduces the pedaling effects of an original performance with high accuracy. The actuator comprises a solenoid, a permanent magnet, a velocity sense coil, and a Hall-effect sensor. The Hall-effect sensor provides an indication of the displacement of the solenoid plunger in accordance with an inverse-square law. Closed-loop feedback control is provided to effect a very true reproduction of pedaling effects. Automatic calibration allows for simple installation.

Method and system for automatic calibration of pedal actuator in a reproducing piano

A method and system for controlling actuators in a mechanical reproducing piano or other instrument. In one implementation, a single finite state machine is provided to control all the actuators. The finite state machine may be or include a shift register or a toggle register, which increases the operating speed. When a note is to be played, the desired dynamic is mapped into a start vector and a stop vector. The actuator is turned on when the state of the finite state machine is equal to the start vector, and is turned off when the state of the finite state machine is equal to the stop vector. Furthermore, the period of the finite state machine is adjusted to be directly proportional to the supply voltage. This allows notes to be played at the desired dynamics even when the supply voltage fluctuates.

System and method for driving actuators in a reproducing piano

The keys in a reproducing piano are actuated by a plurality of solenoids, one for each key to be played. The solenoids are arranged along the width of the keyboard and deviated from each other in the front-back direction of the keys in a staggered manner. A consequence of this arrangement is that the mechanical lever advantage of some solenoids is greater than the mechanical lever advantage of others, and as a result, some keys are played more loudly than others. In order to correct this problem, the drive applied to a solenoid is adjusted to compensate for the mechanical lever advantage, thereby allowing a performance to be accurately reproduced.

System and method for actuating keys with different lever advantages

System and method for driving actuators in reproducing piano

A hammer sensor incorporated in a keyboard musical instrument monitors a motion of each hammer assembly, and a controller not only determines a hammer velocity and an impact time for generating a set of music data codes representative of a music performance but also measures an actual distance between the hammer sensor and an impact point against a music string on the basis of a forward trajectory and a backward trajectory measured by the hammer sensor; thereby allowing a worker to easily adjust the hammer sensor to an appropriate position.

Keyboard musical instrument equipped with built-in distance measuring

A piano is equipped with electromechanical actuators which are individually associated with and operate the keys to reproduce a piano performance. The actuators are selectively energized according to the notes to be played to recreate a piano performance. When an actuator is energized, individual pulses of uniform width are selected from a pulse train and applied to the actuator, with the number of selected pulses varying the overall drive energy supplied to the actuator to closely approximate a desired drive or note intensity.

Method and apparatus for producing variable intensity in a piano

A reproducing piano is provided which is capable of reproducing the notes of a chord or a sequence of multiple intensity notes within several groups of common intensity. This is accomplished by sorting the notes into a plurality of groups and then assigning intensity levels to the various groups so that notes within a group will be played at the same intensity. A limited number of solenoid driver circuits are multiplexed among the solenoids according to the grouping of notes, thereby providing faithful reproduction of the music, but at a lower cost than by individual control of each key.

Multiplexed multiple intensity reproducing piano

There is disclosed a method and apparatus for reproducing in a player piano the pedal mechanism movements which approximate those of the original performance from a tape or other recording medium on which has been recorded data representative of the sequential positions of the piano pedal mechanisms during the original performance. A playback mechanism reads the desired pedal positions from a digitally encoded tape, and this is converted to an analog voltage representative of the desired pedal position. The voltage is then differentiated as a function of time to produce a voltage that is representative of the velocity of the pedal mechanism. A velocity sensor in the form of a permanent magnet within a coil senses the movement of the pedal mechanism in the reproducing piano to create a second signal proportional to the actual velocity of the pedal mechanism. These two signals are compared and applied through an operational amplifier to the solenoid which moves the pedal mechanism in the player piano, thereby approximating the movement of the pedal mechanism during the recorded performance.

Method and apparatus for reproducing pedaling effects in a piano

A grand piano or a vertical piano is equipped with a proportional sensor and a proportional actuator, both connected to the damper lifter tray (in a grand piano) or damper actuator bar (in a vertical piano). During a piano performance the instantaneous position of the lifter tray or actuator bar as the case may be is sensed and recorded, in addition to the keyboard activity. At a later time when the performance is reproduced, the actuator positions the lifter tray or actuator bar, as the case may be, in such a way that the dampers are positioned in an imitation of the way they were positioned during the original performance. The result is that subtle pedalling effects formerly lost are accurately reproduced. The method and apparatus of the invention apply equally well to the soft pedal as to the sustaining pedal, both of which affect the vibrating characteristics of the piano strings.

Method and apparatus for recording and reproducing pedalling effects in

The dynamics of a piano performance are measured by measuring the dynamics of each individual note played. This measurement is accomplished by measuring the 'near terminal velocity' of the hammer shank associated with each note, the velocity determining the 'loudness' of the note. In order to make this velocity measurement without affecting appreciably the 'feel' of the piano, a notched shutter is secured to the hammer shank for the particular hammer associated with each note for cooperation with an optical switch (light source and photo cell). When any one note is played, the corresponding hammer shank will move upwardly to cause the hammer to strike the appropriate piano string and in the upward movement, the top of the shutter will intercept the optical switch to generate an initiating signal. This initiating signal starts a count in an electronic counter. As the shank continues to move upwardly, the bottom edge of the notch will generate an end-of-count signal which will terminate the count in the electronic counter. The time increment defined by the count is inversely proportional to the 'near terminal velocity' of the hammer.

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Los Angeles, CA, United States of America

Wayne L Stahnke