Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method and apparatus for altering the solenoid drive during playback in a reproducing piano to prevent double hammer strikes. The key is depressed by a solenoid under constant velocity until the point of let-off, and the velocity is then increased to accelerate the continued movement of the key and action so that the hammer rebounding from the string will fall without rebounding from the action against the string a second time. In a preferred embodiment, a microprocessor evaluates the key velocity drive value, and if the velocity called for is above a predetermined level, then no boost is applied to the solenoid.

Abstract: 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.

Abstract: 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.