Automatic player musical instrument, testing system incorporated therein and method for specifying half pedal point

A testing system is incorporated in an automatic player piano for specifying a half pedal point of a damper pedal at which the loudness of tones is lessened, and an automatic player moves the damper pedal to the half pedal point so as to lessen the loudness of tones in an automatic playing; the testing system accumulates pieces of experimental data expressing relation between the loudness of tones and a current pedal position of the damper pedal, and searches the pieces of experimental data for points of reflection; and the testing system determines the half pedal point through an internal division on the line between the points of reflection.

FIELD OF THE INVENTION

This invention relates to an automatic player musical instrument and, more particularly, to an automatic player musical instrument capable of re-producing a half-pedal in a playback and a method for determining half pedal region, a testing system for determining the half pedal point and a method for determining the half pedal point.

DESCRIPTION OF THE RELATED ART

An automatic player piano is a typical example of the automatic player musical instrument, and is broken down into an acoustic piano and an automatic playing system. The automatic playing system includes a controller, solenoid-operated key actuators and solenoid-operated pedal actuators, and the solenoid-operated key actuators and solenoid-operated pedal actuators are respectively provided in association with the array of black keys and white keys incorporated in the acoustic piano and the pedals of the acoustic piano. While the automatic playing system is reenacting a performance on the acoustic piano, the controller sequentially supplies key driving signals to the solenoid-operated key actuators so as to give rise to the key movements as similar to the original performance. The controller further supplies pedal driving signals to the solenoid-operated pedal actuators so as to move the pedals over the stroke equal to that in the original performance. Thus, the automatic playing system makes the predetermined pedal effects imparted to the acoustic piano tones.

One of the pedals is called as a “damper pedal”. Pianists can give two pedals effects to the acoustic piano tones by means of the damper pedal. A pianist is assumed to make the damper pedal remain at the rest position. The dampers are held in contact with the associated strings on the condition that the black keys and white keys stay at the rest positions, and the dampers prevent the strings from vibrations. The pianist is assumed to depress a white key. The white key causes the damper spaced from the string on the way toward the end position, and the damper permits the associated string freely to vibrate. When the associated action unit escapes from the hammer, the hammer starts to rotate toward the string. The hammer is brought into collision with the string, and gives rise to vibrations. The acoustic piano tone is produced through the vibrations of strings. The damper is brought into contact with the vibrating string on the way toward the rest position, and the vibrations and, accordingly, the acoustic piano tone are decayed. Thus, the dampers behaves as usual on the condition that the damper pedal stays at the rest position. Any pedal effect is not imparted to the acoustic piano tones. The region of pedal stroke to cause the damper fully to exert the weight on the string is hereinafter referred to as a “restricting region”.

When the pianist depresses the damper pedal to the end position, the damper remains spaced from the strings after release of the depressed keys so that the acoustic piano tones are prolonged. This pedal effect is hereinafter referred to as a “full stroke pedal effect”. The region of pedal stroke to make the dampers perfectly spaced from the strings is referred to as a “damper-free region”.

If the pianist keeps the damper pedal on the way to the end position, the dampers have removed part of the weight thereof from the associated strings, but are still in contact with the strings. In this situation, the depressed keys cause the associated hammers to be brought into collision with the strings, and give rise to the vibrations of strings. However, the dampers do not allow the strings freely to vibrate. As a result, the acoustic piano tones are produced from the weakly vibrating strings at small loudness. This pedal effect is hereinafter referred to as a “half pedal effect”, and the range of pedal stroke to impart the half pedal effect is referred to as a “half pedal region”.

In order to produce the acoustic piano tones at high fidelity, the pedals of acoustic piano are to be moved in such a manner that the pedal effects are exactly imparted to the acoustic piano tones. In case where an original performance is recorded on the acoustic piano combined with the automatic playing system, the controller is only expected to move the pedals over the stroke equal to that in the original performance. However, if the automatic playing system reenacts the original performance on an acoustic piano different from the acoustic piano used for the recording, there is a possibility that the pedal effects, which are different from those in the original performance, may be imparted to the acoustic piano tones, because the half pedal region of another acoustic piano is not equal to that of the acoustic piano used in the original performance.

In order to reproduce the acoustic piano tones at high fidelity, the restricting region, half pedal region and full stroke region are to be individually determined through a test before the automatic playing.

A prior art testing method is disclosed in Japanese Patent No. 2606616. According to the Japanese Patent, the controller stepwise increases the duty ratio of driving pulse signal, and measures the pedal stroke. Although the duty ratio is constantly increased, the rate of change in the pedal stroke is varied. Although the weight of damper is born by the strings in the restricting region, the load on the strings is gradually decreased in the half pedal region, and, finally, all the load are born by the foot of the player. For this reason, the rate of change is to be smaller in the half pedal region rather than that in the restricting region. The controller accumulates pieces of pedal stroke data expressing the ascent of the plunger of solenoid-operated pedal actuator, and searches the pieces of pedal stroke data for the point of inflection so as to determine the boundary between the restricting region and the half pedal region at the point of inflection.

However, the point of inflection is not clearly discriminative. Therefore, the result of the prior art test is not reliable. In other words, it is hard exactly to specify the boundary of the half pedal region through the prior art method.

As well know to the persons skilled in the art, the dampers for the strings in the lower pitched part are larger and heavier than the dampers for the strings in the higher pitched part are, and the array of dampers are supported by the lifter bar at a middle point of the array. When the damper pedal is depressed, the force is transmitted to the lifter bar, and the lifter bar pushes the array of dampers, upwardly. Although the dampers for the strings in the higher pitched part are promptly lifted up, the dampers for the strings in the lower pitched part tend to be left on the associated strings. On the contrary, while the damper pedal is returning to the rest position, the dampers for the strings in the lower pitched part are firstly brought into contact with the associated strings, and, thereafter, the dampers for the strings in the lower pitched part reach the associated strings. Irregularity is found in the movement of dampers, and the inflection point of a certain damper does not stand for the movement of the array of dampers. In fact, when the boundary of the half pedal region is determined at the inflection point, the boundary of the half pedal region is not always consistent with a boundary of the half pedal region decided by a human tuning worker.

SUMMARY OF THE INVENTION

It is therefore an important object of the present invention to provide an automatic player musical instrument, which exactly determines a half pedal point in the half pedal region of the acoustic musical instrument by itself.

It is another important object of the present invention to provide a testing system, which determines the half pedal point for the automatic player musical instrument.

It is also an important object of the present invention to provide a method for exactly determining the half pedal point in the half pedal region.

To accomplish the object, the present invention proposes to put a target position of a manipulator for imparting one of the effects imparted to tones by means of the manipulator on the basis of the magnitude of vibrations varied with a current position of the manipulator.

In accordance with one aspect of the present invention, there is provided an automatic player musical instrument for producing tones without a fingering of a human player comprising a musical instrument including plural manipulators selectively moved for specifying the tones to be produced, a tone generating system connected to the plural manipulators and producing the tones specified with the manipulators, another manipulator connected to the tone generating system, and imparting an effect selected from effects to the tones depending upon a current position of the aforesaid another manipulator, an automatic playing system provided in association with the plural manipulators and the aforesaid another manipulator so as selectively to move the plural manipulators for specifying the tones and the aforesaid another manipulator for imparting the effect to the tones, and a testing system determining a target position of the aforesaid another manipulator for imparting one of the effects to the tones through an experiment, informing the automatic playing system of the target position and including an exciter giving rise to at least one of the tones through vibrations in the tone generating system, a driver moving the aforesaid another manipulator for varying the current position, a converter converting vibrations expressing the at least one of the tones to pieces of experimental data expressing magnitude of the vibrations varied together with the current position and an information processor connected to the converter and determining the target position on the basis of at least one point of reflection found in plots expressing relation between the magnitude and the current position.

In accordance with another aspect of the present invention, there is provided a testing system determining a target position of a manipulator for imparting one of effects to tones produced in an automatic player musical instrument through an experiment, and the testing system comprises an exciter giving rise to at least one of the tones through vibrations in a tone generating system of the automatic player musical instrument, a driver moving the manipulator for varying a current position of the manipulator, a converter converting vibrations expressing the aforesaid at least one of the tones to pieces of experimental data expressing magnitude of the vibrations varied together with the current position and an information processor connected to the converter and determining the target position on the basis of at least one point of reflection in plots expressing relation between the magnitude and the current position.

In accordance with yet another aspect of the present invention, there is provided a method of specifying a target position of a manipulator incorporated in an automatic player musical instrument for imparting an effect to tones produced in the automatic player musical instrument, the method comprises the steps of a) giving rise to at least one tone in the automatic player musical instrument, b) moving the manipulator so as to vary a current position of the manipulator, c) accumulating pieces of experimental data expressing relation between magnitude of vibrations representative of the aforesaid at least one tone and the current position during the movement of the manipulator, d) searching the piece of experimental data for at least one point of reflection and e) specifying the target position on the basis of the at least one point of reflection.

The target position may be determined through an internal division on a line drawn between two points of reflection representative of boundaries of a certain region in which the effect is imparted to the tones.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An automatic player musical instrument embodying the present invention largely comprises a musical instrument, an automatic playing system and a testing system. The automatic playing system and testing system are installed in the musical instrument. A human player fingers a music tune on the musical instrument without any assistance of the automatic playing system, and the automatic playing system is used for producing tones without the fingering of human player.

The musical instrument includes plural manipulators, a tone generator and another manipulator. The plural manipulators are selectively moved by the human player or automatic playing system for specifying the tones to be produced. The plural manipulators are connected to the tone generating system, and the tone generating system produces the tones specified with the manipulators. The manipulator is also connected to the tone generating system, and the human player or automatic playing system imparts an effect to the tones. The manipulator is available for plural effects, and the tone generating system determines the effect to be imparted to the tones depending upon a current position of the manipulator.

It is important for the automatic playing system exactly to move the manipulator to a target position for imparting the effect imparted same as that in an original performance on the musical instrument. The target position is specifies by the testing system through an experiment, and informs the automatic playing system of the target position

The testing system includes an exciter, a driver, a converter and an information processor. A particular feature of the testing system is directed to the information processing on pieces of experimental data expressing the magnitude of vibrations of tones. Human players and audience recognize the effect of tones through their ears. Similarly, the testing system specifies the target position on the basis of the vibrations of tones so that the effect imparted at the target position specified by the testing system is quite close to the effect recognized by the human players and audience.

In the experiment, the exciter gives rise to at least one of the tones through vibrations in the tone generating system, and the driver moves the manipulator in the generation of tone for varying the current position. The converter converts the vibrations expressing the tone to pieces of experimental data expressing magnitude of the vibrations varied together with the current position. The information processor is connected to the converter so as to accumulate the pieces of experimental data. The information processor determines the target position on the basis of at least one point of reflection found in plots expressing relation between the magnitude and the current position. Thus, the target position is determined on the basis of the magnitude of vibrations of tone. The target position thus determined is highly reliable.

In the following description, term “front” is indicative of a position closer to a human player, who sits on a stool for fingering, than a position modified with term “rear”. A line drawn between a front position and a rear position extends in a “fore-and-aft direction”, and a “lateral direction” crosses the fore-and-aft direction at right angle. An “up-and-down direction” is normal to a plane defined by the fore-and-aft direction and the lateral direction.

First Embodiment

An automatic player piano embodying the present invention largely comprises an automatic playing system10, a grand piano30and a pedal testing system60. A human player performs a piece of music on the grand piano30without any assistance of the automatic playing system10. The automatic playing system10is installed in the grand piano30, and reenacts a performance on the grand piano30without any participation of a human player. The pedal testing system60carries out a test on the grand piano30, and determines a half pedal point in a half pedal region. In this instance, the half pedal point is expressed as a pedal stroke from the rest position in millimeters. The boundary between the restricting region and the half pedal region can serve as the half pedal point. The half pedal region has been hereinbefore described, and the half pedal point is an arbitrary point in the half pedal region to which the damper pedal PD1is moved for imparting a half pedal effect in the automatic playing.

Although a recording system forms a part of the automatic playing piano, description on the recording system is omitted for the sake of simplicity.

The grand piano30includes a keyboard31having black keys31aand white keys31b, hammers32, action units33, strings34, dampers36, a pedal system71and a piano cabinet72. An inner space is defined in the piano cabinet72, and the action units33, hammers32, dampers36and strings34occupy the inner space. A key bed72aforms a part of the piano cabinet72, and the keyboard31is mounted on the key bed72a.

The black keys31aand white keys31bare laid on the well-known pattern, and extend in parallel to the fore-and-aft direction. Pitch names are respectively assigned to the black keys31aand white keys31b. Balance key pins31coffer fulcrums to the black keys31aand white keys31bon a balance rail31d. Capstan buttons31eare upright on the rear portions of the black keys31aand the rear portions of the white keys31b, and are held in contact with the action units33. Thus, the black keys31aand white keys31bare respectively linked with the action units33so as to actuate the action units33during travels of keys31a/31bfrom rest positions toward end positions.

While the weight of action units33are being exerted on the rear portions of black keys31aand the rear portions of which keys31bwithout another sort of force, the black keys31aand white keys31bstay at the rest positions, respectively. While a human player is depressing the front portions of black keys31aand the front portions of white keys31b, the front portions are sunk, and the black keys31aand white keys31btravel from the rest positions to the end positions.

The action units33are provided in association with the hammers3. The actuated action units33make human players feel the unique piano key touch, and give rise to rotation of the associated hammers32.

The strings34are stretched over the array of hammers32and a sound board28, and the hammers3are respectively opposed to the strings34. The dampers36are spaced from and brought into contact with the strings34depending upon the key position. While the black keys31aand white keys31bare staying at the rest positions, the dampers36are held in contact with the strings34, and the weight of dampers36is born by the strings34. Namely, the dampers36are found at the restricting region.

When the black keys31aand white keys31breach certain points on the way toward the end positions, the dampers36start to leave the strings34. While the weight of dampers36is being left on the strings, the dampers36are held in contact with the strings34, and are found in the half pedal region. When the weight of dampers36is perfectly removed from the strings, the dampers36are spaced from the strings4, and enter the damper free region. As a result, the dampers36permit the strings34to vibrate. After entry into the damper free region, the action units33give rise to the rotation of hammers32. The hammers32are brought into collision with the associated strings34at the end of the rotation, and rebound on the strings34. Thus, the hammers32give rise to vibrations of the associated strings34, and the vibrations are transmitted from the strings34to the sound board28. The acoustic piano tones are produced through the vibrations of the strings34at the pitch names identical with those assigned to the associated black and white keys31a/31b.

When the human player releases the black keys31aand white keys31b, the black keys31aand white keys31astart to return toward the rest positions. The dampers39are getting closer and closer to the associated strings34, and are brought into contact with the vibrating strings34on the way of keys31a/31btoward the rest positions. The dampers36prohibit the strings34from the vibrations. As a result, the acoustic piano tones are decayed.

The pedal system71includes three pedals PD1, PD2and PD3and three link works71a,71band71c. The pedals PD1, PD2and PD3are called as a “damper pedal”, a “sostenuto pedal” and a “soft pedal”, respectively, and the link works71a,71band71care connected between the pedals PD1, PD2and PD3and the lifting rail, a sostenuto rod and a key frame, respectively. When the damper pedal PD1is depressed to the end position, the acoustic piano tones are prolonged. The sostenuto pedal PD2is used for independently prolonging the acoustic piano tones, and the soft pedal PD3is depressed in order to reduce the loudness of the acoustic piano tones.

The automatic playing system10includes solenoid-operated key actuators20with built-in plunger position sensors20a, solenoid-operated pedal actuators26with built-in plunger position sensors27, a piano controller40, a motion controller41and a servo controller42. The piano controller40, motion controller41and servo controller42stand for functions of a controlling unit10a, and the functions are realized through execution of subroutine programs of a computer program.

A slot72bis formed in the key bed72abelow the rear portions of the black and white keys31aand31b, and extends in the lateral direction. The solenoid-operated key actuators20are arrayed inside the slot72b, and each of the solenoid-operated key actuators20has a plunger20band a solenoid20c.

The solenoids20care connected in parallel to the servo controller42, and are selectively energized with driving signal uk(t) so as to create respective magnetic fields. The plungers20bare provided in the magnetic fields so that the magnetic force is exerted on the plungers20b. The magnetic force causes the plungers20bto project in the upward direction, and the rear portions of the black and white keys31aand31bare pushed with the plungers20bof the associated solenoid-operated key actuators20. As a result, the black and white keys31aand31bpitch up and down without any fingering of a human player. The servo controller42varies the amount of mean current of the driving signal uk(t) so as to control the magnetic force. In this instance, the driving signals uk(t) is supplied to the solenoids20cas a pulse train, and the duty ratio is varied in order to control the magnetic force. In other words, the driving signal uk(t) is a pulse width modulation signal.

The built-in plunger position sensors20arespectively monitor the plungers20b, and supply plunger position signals yk representative of current plunger position to the servo controller42. The black keys31aand white keys31bare moved together with the plungers20bso that the current plunger positions are equivalent to current key positions. Thus, the built-in plunger position sensors20aindirectly monitor the black keys31aand white keys31b.

The solenoid-operated pedal actuators26are provided in association with the damper pedal PD1, sostenuto pedal PD2and soft pedal PD3, respectively, and move the pedals PD1, PD2, PD3without any step-on of a human player. Solenoids26aof the pedal actuators26are connected in parallel to the servo controller42, and driving signals up(t) are selectively supplied to the solenoid-operated pedal actuators26. The driving signals up(t) create magnetic fields around plungers26bof the solenoid-operated pedal actuators26, and the pedals PD1, PD2and PD3are pushed down with the plungers26b. The pedal stroke is depending upon the strength of magnetic fields so that the serve controller42controls the pedal stroke by varying the amount of mean current of the driving signals up(t). The built-in plunger position sensors27monitor the plungers26b, and supply plunger position signals yp to the servo controller42. In this instance, the servo controller42varies the duty ratio of the driving signal up(t) so as to control the pedal stroke. In other words, the driving signal up(t) is a pulse width modulation signal.

A performance is expressed by pieces of music data, and the pieces of music data are given to the piano controller40in the form of music data codes. In this instance, the music data codes are prepared in accordance with the MIDI (Musical Instrument Digital Interface) protocols.

The piano controller40is communicable with a data storage where a music data file is stored. In the automatic playing, the piano controller40periodically searches the music data file for a music data code to be presently processed. When the piano controller40finds the music data code or codes to be presently processed, the piano controller40supplies the music data code or codes to the motion controller41.

The motion controller41determines a series of values of target key position rk and a series of values of target pedal position rp. The target key position rk and target pedal position rp are varied with time. The target key position rk and target pedal position rp are timely supplied from the motion controller41to the servo controller42.

The servo controller42compares the target key position rk and target pedal rp with the current key position yk and current pedal position yp, which are respectively supplied from the built-in plunger position sensor20aand built-in plunger position sensor27, and determines the amount of means current or duty ratio of the driving signal uk(t) and the amount of mean current or duty ratio of the driving signal up(t) through the comparison. If the current key positions yk and current pedal position yp are found to be at the back of the target key position uk(t) and target pedal position up(t), the servo controller42increases the duty ratio of the driving signals uk(t) and up(t) so that the black keys31a, white keys31band pedals PD1, PD2and PD3are accelerated. On the other hand, if the current key positions yk and current pedal position yp are found to be in front of the target key position uk(t) and target pedal position up(t), the servo controller42decreases the duty ratio of the driving signals uk(t) and up(t) so that the black keys31a, white keys31band pedals PD1, PD2and PD3are decelerated. Thus, the servo controller42accelerates and decelerates the black keys31a, white keys31band pedals PD1, PD2and PD3so as to force the black keys31a, white keys31band pedals PD1, PD2and PD3to trace the series of values of target key position and series of values of target pedal position.

The pedal testing system60includes the servo controller42, motion controller41, piano controller40and a vibration sensor51. Thus, the servo controller42, motion controller41and piano controller40are shared between the automatic playing system10and the pedal testing system60. The vibration sensor51, piano controller40, motion controller41and servo controller42cooperate with the vibration sensor51, and determine the half pedal point in the half pedal region through an experiment.

The vibration sensor51converts the vibrations of strings34to a detecting signal ys indicative of the strength of vibrations. In this instance, the vibration sensor51is implemented by a combination of a piezoelectric element51aon the sound board28, a microphone52over the sound board28and three electromagnetic pickup units53in the vicinity of predetermined strings34. In this instance, the predetermined strings34are selected from the lower pitched part, middle pitched part and higher pitched part, respectively. The vibration sensor51outputs the detecting signal ys, and the detecting signal ys is supplied to the servo controller42. In this instance, the three sorts of vibration-to-electric signal converters51a,52and53produce analog signals, and the detecting signal ys stands for these analog signals. The analog detecting signal ys is converted to a digital detecting signal ys before a data processing as will be described in conjunction with the system configuration of the controlling unit10a.

Turning back toFIG. 1, an array of key position sensors37ais provided below the front portions of the black and white keys31a/31b, and monitors the black and white keys31a/31b, respectively. An array of hammer position sensors37bis provided over the hammers32, and monitors the hammers32. The key position sensors37aand hammer position sensors37bform parts of the recording system, and a performance on the grand piano30is recorded through the recording system.

A hammer stopper80is provided over the array of hammers32, and an electric motor81is connected to the hammer stopper80. The hammer stopper80extends in the lateral direction, and is changed between a free position and a blocking position. While the hammer stopper80is staying at the free position, the hammers32are brought into collision with the strings34without any interruption of the hammer stopper80, and rebound on the strings34. When the electric motor81rotates the hammer stopper80from the free position to the blocking position, the hammer stopper80enters the orbits of hammers. In this situation, the hammers32rebound on the hammer stopper80without any strike at the strings34, and any acoustic piano tone is not produced. Though not shown inFIG. 1, an electronic tone generator and effectors are incorporated in the controlling unit10a, and produce music data codes on the basis of the signals supplied from the key position sensors37aand hammer position sensors37b. The music data codes are finally converted to electronic tones through speakers of a sound system.

FIG. 3shows the system configuration of the controlling unit10a. The controlling unit10aincludes pulse width modulators10b/10c, analog-to-digital converters10d/10e/10f, a central processing unit11, which is abbreviated as “CPU”, a read only memory12, which is abbreviated as “ROM”, a random access memory13, which is abbreviated as “RAM”, an MIDI interface14, a shared bus system15, timers16, a display driver17, an external memory device18, a manipulating board19, an electronic tone generator21, effectors22and a flash memory25. The central processing unit11is connected to the shared bus system15, and is communicable with the other system components10b,10c,10d,10e,10f,12,13,14,16,17,18,19,21and22through the shared bus system15.

The central processing unit11is an origin of the information processing capability of the controlling unit10a, and accomplishes given tasks through execution of instruction codes.

The instruction codes are stored in the read only memory12together with pieces of test data, pieces of image data and other control parameters in the non-volatile manner, and form a computer program. The computer program expresses the tasks, and runs on the central processing unit11. The computer program is hereinlater described in detail.

The random access memory13and extended memory19offer a temporary data storage to the information processor10, and flags are defined in predetermined memory locations. For example, the pieces of test data and pieces of music data are, by way of example, stored in the temporary data storage in the random access memory22, and pieces of experimental data are accumulated in the random access memory13during the execution of a subroutine program for the half pedal region.

The MIDI interface14is provided for communication with another musical instrument designated on the MIDI protocols. Music data codes may be supplied through the MIDI interface14between the musical instrument and the controlling unit10a.

The timers16independently measure the lapse of time. One of the timers16is assigned to measurement of a time period between a note-on/note-off event and the previous note-on/previous note-off event. Another timer16gives timings for timer interruptions.

The display driver17is connected to a panel display unit (not shown) such as a liquid crystal display panel, and produces an image or images on the panel display unit. Current status of the automatic player piano and prompt messages are delivered to users through the panel display unit. An image of a music score is produced on the panel display unit on the basis of the pieces of image data under the control of the central processing unit11.

The external memory device18has a huge data holding capability in the non-volatile manner. A flexible disk driver and flexible disks, or a compact disk driver and compact disks serve as the external memory18. Music data files may be transferred from the external memory device18to the random access memory13before the automatic playing.

Various switches are provided on the manipulating board19. One of the switches is a power switch, and a user activates the controlling unit10aby turning on the power switch. Users give their instructions to the controlling unit10athrough the manipulating board19. A user changes the automatic player piano among the automatic playing, mute playing, test and so forth through some switches, and selects a tune to be played from a list of music data files.

The electronic tone generator21includes a waveform memory, plural read-out circuits and a key assigner, and cooperates with effectors22. The key assigner assigns the note-on events, which the music data codes express, to the read-out circuits, and the read-out circuits make pieces of waveform data read out from the waveform memory. A digital audio signal is produced from the pieces of waveform data. Certain music data codes stand for the effects of the pedals PD1, PD2and PD3, and the digital audio signal is modified through the effectors22in the presence of the certain data codes. The music data codes are produced through the fingering on the keyboard31, or are supplied from the outside of the mute piano.

The effectors22vary the electronic tones depending upon the current pedal positions of the pedals PD1, PD2and PD3. While the damper pedal PD1is, by way of example, staying at the restricting region, any effect is not given to the electronic tones. The effectors22give the half-pedal effect, through which the tones are reduced in loudness, to the electronic tones in the half pedal region, and give a damper effect, through which the tones are prolonged, to the electronic tones in the damper-free position.

The electronic tone generator21is connected to the sound system23directly or through the effectors22. The sound system23includes a digital-to-analog converter, a preliminary amplifier, a main amplifier and loud-speakers, in which a headphone speaker is included. The digital audio signal is converted to an analog audio signal, and the electronic tones are radiated from the loud speakers of the sound system23.

The flash memory25has a large data holding capability, and music data files are stored in the flash memory25in the non-volatile manner.

The pulse width modulators10band10care respectively provided for the solenoid-operated pedal actuators26and solenoid-operated key actuators20. Pieces of control data expressing the target duty ratio are supplied from the central processing unit11to the pulse width modulators10band10c. Then, the pulse width, modulators10band10cadjust the driving signals uk(t) and up(t) to the target duty ratio, and supply the driving signals uk(t) and up(t) to the solenoids20cof solenoid-operated key actuators20and the solenoids26aof solenoid-operated pedal actuators26so as to give rise to the movements of specified keys31a/31band the movements of specified pedals PD1, PD2and PD3.

The analog-to-digital converters10d,10eand10fare connected between the plunger position sensors27/20a, vibration sensors51and hammer sensors/key sensors37a/37band the shared bus system15. The analog plunger position signals yk/yp, analog detecting signal ys, analog key position signals and hammer position signals are periodically sampled and converted to digital plunger position signals, digital detecting signal ys, digital key position signals and digital hammer position signals. These digital signals are hereafter labeled with the reference same as those designating the corresponding analog signals. Since data buffers are incorporated in the analog-to-digital converters10d,10eand10f, the central processing unit11periodically fetches the digital signals from the data buffers, and stores the pieces of plunger position data, pieces of loudness data represented by the detecting signal ys, pieces of key position data and pieces of hammer position data in the random access memory13.

Subsequently, description is made on the computer program. The computer program is broken down into a main routine program and subroutine programs. While the main routine program is running on the central processing unit11, users can communicate with the central processing unit11through the manipulating board19. The main routine program periodically branches to the subroutine programs.

The central processing unit11periodically fetches the pieces of pedal position data expressing the current pedal position, pieces of loudness data expressing the loudness of acoustic piano tones, pieces of key position data expressing the current key positions and pieces of hammer position data expressing the current hammer positions through the execution on one of the subroutine programs, and stores them in the random access memory13.

Another of the subroutine program is assigned to the automatic playing. When a user instructs the automatic playing system10to perform a tune on the grand piano30, the central processing unit raises a flag indicative of the automatic playing. Upon entry into the subroutine program for the automatic playing, the central processing unit11checks the flag to see whether or not the user has instructed the automatic playing to the automatic playing system10. If the answer is given negative, the central processing unit11immediately returns to the main routine program. On the other hand, if the answer is given affirmative, the piano controller40, motion controller41and servo controller42are realized through the execution of the remaining instruction codes of the subroutine program for the automatic playing.

The half pedal point is determined through execution of another subroutine program, which is hereinafter described in detail. Since the pedal stroke to enter the half pedal region is not constant among the acoustic pianos, the testing system60determines the half pedal point through an experiment on the grand piano30. When a tuner, a worker or a user requests the testing system60to determine the half pedal point through the manipulating board19, the central processing unit11raises the flag indicative of the test, and starts periodically to enter the subroutine program for the half pedal point.

FIG. 4shows the job sequence of the subroutine program for the half pedal point. A worker is assumed to instruct the testing system60to determine the half pedal point through the manipulating board19. The central processing unit11acknowledges the instruction, and raises the flag indicative of the determination of half pedal point. When the main routine program branches to the subroutine program, the central processing unit11proceeds to the job sequence shown inFIG. 4.

The central processing unit11makes the pulse width modulator10cto drive a black key31aor a white key31bby means of the associated solenoid-operated key actuator20for producing an acoustic piano tone through the strike at the string34. Thereafter, the central processing unit11makes the pulse width modulator10bto drive the damper pedal PD1for a travel from the end position to the rest position by means of the associated solenoid-operated pedal actuator26, and starts the timer to measure the lapse of time.

The central processing unit11periodically fetches the digital detecting signal ys expressing the loudness of the acoustic piano tone and the output signal of the timer expressing the lapse of time, and accumulate the pieces of loudness data and pieces of time data as pieces of experimental data. The central processing unit11determines an envelope CA of plots expressing the peaks of the waveform expressing the acoustic piano tones as by step S101. Pieces of envelope data express the envelope of plots CA, and the envelope CA is shown inFIG. 5A. In order to accumulate the pieces of experimental data, the damper pedal PD1is moved in uniform motion from the end position to the rest position so that the pedal position or pedal stroke is varied as indicated by plots CB inFIG. 5B.

In order to move the damper pedal PD1in uniform motion, the piano controller40reads out the pieces of test data expressing a reference pedal trajectory from the read only memory12, and transfers the pieces of test data to the motion controller41. The reference pedal trajectory is a series of values of target pedal position varied with time. The damper pedal PD1is moved on the reference pedal trajectory at high speed. The pedal velocity is large enough to make the damper pedal PD1brought into contact with the vibrating strings34for restricting the vibrations. In this instance, the time period from the initiation of pedal movement to the contact with the vibrating strings34is of the order of 2.5 seconds.

The motion controller41reads out the present time from the timer16, and determines a value of target pedal position rp at the present time. The value of target pedal position rp is supplied from the motion controller41to the servo controller42.

The servo controller42fetches the piece of plunger position data expressing the current plunger position and current pedal position yp from the data buffer of the analog-to-digital converter10d, and compares the target pedal position rp with the current pedal position yp to see whether or not a stroke difference ep is found between the target pedal position rp and the current pedal position yp. If the current pedal position yp is consistent with the target pedal position rp, the servo controller42keeps the duty ratio of the driving signal up(t). When the stroke difference ep is found between the current pedal position yp and the target pedal position rp, the servo controller42determines a target duty ratio up through an amplification of the stroke difference ep. The target duty ratio up is determined in order to minimize the stroke difference ep.

The pulse width modulator10badjusts the driving signal up(t) to the target duty ratio, and supplies the driving signal up(t) to the solenoid26a. The above-described control loop is repeated during the travel of the damper pedal PD1so as to force the damper pedal PD1to travel on the reference pedal trajectory.

The jobs at step S101is illustrated in more detail inFIG. 7. The central processing unit11fetches the pieces of test data from the read only memory12as by step S201. The pieces of test data express a reference pedal trajectory.

The central processing unit11supplies a piece of control data expressing the movement of the damper pedal PD1to the end position to the pulse width modulator10b, and the pulse width modulator10bsupplies the driving signal up(t) to the solenoid-operated pedal actuator27associated with the damper pedal PD1. Then, the solenoid-operated pedal actuator26downwardly projects the plunger26b, and the damper pedal PD1is moved to the end position as by step S202.

Subsequently, the central processing unit11supplies pieces of control data expressing the movement of predetermined keys31a/31bto the end positions to the pulse width modulator10c. The pulse width modulator10csupplies the driving signals uk(t) to the solenoid-operated key actuators20associated with the predetermined keys31a/31b. The driving signals uk(t) make the plungers20bupwardly project from the solenoids20cso that the predetermined keys31a/31bare moved toward the end positions. The associated action units33are actuated by the predetermined keys31a/31b, and cause the hammers32to rotate toward the strings34. The hammers32are brought into collision with the strings34at the end of the rotation, and give rise to the vibrations of the strings34. Thus, the central processing unit11makes the pulse width modulator10cdrive the solenoid-operated key actuators20for striking the strings34with the hammers32as by step S203. The hammer velocity is large enough to keep the strings34vibrating until the dampers36take up the vibrations of strings34.

Three keys31a/31bare selected from the lower pitched part, middle pitched part and higher pitched part, respectively, as the predetermined keys31a/31b. It is desirable to form the at least three acoustic piano tones a chord.

The central processing unit11checks the pieces of pedal position data to see whether or not the damper pedal PD1starts to return toward the rest position. While the answer is given negative, the central processing unit11proceeds to step S206. When the answer is given affirmative, the central processing unit11starts the timer26in order to measure the lapse of time as by step S204. The central processing unit11starts the timer, once. After the initiation of the measurement of the lapse of time, the central processing unit11proceeds to step S205without any execution at step S204.

The central processing unit11periodically checks another timer26to see whether or not the predetermined sampling time period is expired as by step S205. In this instance, the predetermined time period is 4 millisecond. While the timer26is giving the negative answer “No” to the central processing unit11, the central processing unit11waits for the expiry of predetermined sampling time period.

When the predetermined time period is expired, the answer at step S205is given affirmative “Yes”, and the central processing unit11fetches the piece of pedal position data expressing the current pedal position yp from the analog-to-digital converter10d. The central processing unit11determines the target pedal position rp on the reference pedal trajectory as by step S206.

The central processing unit11compares the current pedal position yp and the target pedal position rp so as to determine the stroke difference ep through the calculation as by step S207. The current pedal position yp was stored during the previous execution loop, i.e., from step S204to step S211.

Subsequently, the central processing unit11multiplies the stroke difference ep by a gain, and determines the target duty ratio through the multiplication or amplification as by step S208.

The central processing unit11informs the pulse width modulator10bof the target duty ratio. The central processing unit11makes the pulse width modulator10badjust the driving signal up(t) to the target duty ratio, and the driving pulse signal up(t) is supplied to the solenoid-operated pedal actuator26as by step S209. The solenoid-operated pedal actuator26keeps, accelerates or decelerates the movement of plunger26b.

Subsequently, the central processing unit11fetches the piece of loudness data expressing the magnitude of the detecting signal ys from the analog-to-digital converter10e, and stores the piece of loudness data together with the current pedal position and the piece of time data expressing the lapse of time from the initiation of pedal movement in the random access memory13as a piece of experimental data as by step S210. The central processing unit11resets the timer26to zero for measuring the predetermined sampling time period.

The central processing unit11checks the pieces of test data to see whether or not the damper pedal PD1reaches the end of the reference pedal trajectory as by step S211. If the damper pedal PD1is found to be on the way to the end of reference pedal trajectory, the answer is given negative, and the central processing unit11returns to the step S204. Thus, the central processing unit11reiterates the loop consisting of steps S204to S211until the damper pedal PD1reaches the end of reference pedal trajectory.

When the damper pedal PD1reaches the end of reference pedal trajectory, the answer at step S211is changed to affirmative. Then, the central processing unit11searches the random access memory13for the pieces of loudness data expressing the peaks of the waveform of the acoustic piano tone or waveform of vibrations, and determines the envelope on which the peak values are found as by step S212.

Thus, the central processing unit11accomplishes the jobs at step S101through the execution at steps S201to S212.

Turning back toFIGS. 4,5A and5B, description is made on the jobs after step S101. When the central processing unit11proceeds to step S102, the central processing unit11approximates the curve expressing the envelope CA to a polygonal line L1and L2. The polygonal line L1and L2is determined as follows. Adjacent two plots are selected from the envelope CA, and the central processing unit11calculates difference between values of the magnitude of detecting signal ys at the adjacent two plots to see whether or not the difference is less than a predetermined critical value. If the answer is given affirmative, a line is drawn between the adjacent two plots. The above-described work is carried out from the initiation of pedal motion toward the rest position and the plot pS at which the magnitude of detecting signal ys is zero. In this instance, the envelope CA is approximated to the two linear lines L1and L2, which crosses at plot pE.

Subsequently, the central processing unit11analyzes the envelope CA, and determines the restricting region, half pedal region and damper free region as by step S103. In detail, the gradient of envelope is minimized at plot pE. This is because of the fact that the dampers36are brought into contact with the strings34on the way toward the rest position and that the dampers36become spaced from the strings34on the way toward the end position. Since the magnitude of detecting signal ys is decreased to zero at plot pS. This is because of the fact that the dampers34become effective against the vibrations of the strings34. In other words, when the damper pedal PD1passes the plot pS, the dampers36gradually lose the pressure on the strings34.

From the above-described analysis, the boundary between the restricting region and the half pedal region is determined at the pedal stroke stS inFIG. 5B, and the boundary between the half pedal region and the damper free region is determined at the pedal stroke stE. Thus, the pedal trajectory is divided into the three regions, i.e., the restricting region from the rest position at the pedal stroke of zero to the pedal stroke stS, the half pedal region from the pedal stroke stS to the pedal stroke stE and the damper free region from the pedal stroke stE to the end position.

Finally, the central processing unit11determines the half pedal point as by step S104. The half pedal point is found at a certain pedal stroke in the half pedal region, and the central processing unit11controls the damper pedal PD1to the half pedal point for imparting the half pedal effect to the acoustic piano tones. In this instance, the central processing unit11determines the half pedal point through the internal division. The difference between the pedal stroke stS and the pedal stroke stE is divided at 2:1. The point of internal division at 2:1 is found at the pedal stroke stH. Thus, the half pedal point is determined at the pedal stroke stH. The half pedal point stH is equivalent to the depth of damper pedal at “64” of the MIDI code.

While the automatic playing system10is reenacting a performance, the servo controller42moves the damper pedal PD1to the half pedal point stH in response to the music data code expressing the half pedal effect.

As will be understood from the foregoing description, the testing system60accumulates the pieces of experimental data expressing the relation between the loudness of acoustic piano tones and the pedal stroke, and determines the boundary between the restricting region and the half pedal region and the boundary between the half pedal region and the damper free region on the basis of the rate of change in the loudness. Even though the array of dampers36is inclined in the lateral direction due to the difference in weight of dampers36, the influences of irregularity is taken into the loudness of acoustic piano tones, and the testing system60determines the half pedal region in consideration of the influences of irregularity. Since the pianists and audience recognize the half pedal effect through their ears, the half pedal region thus determined is close to the half pedal region determined by a human tuning worker, and the half pedal point is surely specified in the half pedal region. The automatic playing system controls the damper pedal PD1to the half pedal point stH in the half pedal region so that the half pedal effect is surely reproduced in the automatic playing.

Second Embodiment

Another testing system implementing the second embodiment is same as the testing system60of the automatic playing piano implementing the first embodiment except for jobs at steps S102, S103and S104. The testing system implementing the second embodiment is also incorporated in an automatic playing system, and, for this reason, component parts of the automatic playing system are accompanied with the references designating the corresponding component parts of the automatic playing piano implementing the first embodiment without detailed description.

FIG. 8shows an envelope CAA of plots expressing the waveform of acoustic piano tones produced through the vibrations of the strings34. In this instance, the central processing unit11determines a half pedal point stHA at a predetermined value ysH of the magnitude of detecting signal ys.

The central processing unit11searches the pieces of envelope data expressing an envelope CAA for a value of the magnitude of detecting signal ys closest to the predetermined value ysH. When the central processing unit11finds the value closest to the predetermined value ysH, the central processing unit11determines the time tH at which the value ysH is produced, and reads out the pedal stroke stH at the time tH. The central processing unit11determines the half pedal point at the pedal stroke stH.

The predetermined value ysH is determined by the manufacturer through the experiment on a grand piano same in model as the grand piano30, and is stored in the read only memory12or flash memory25. The black and white keys31a/31bare driven for travel at the key velocity equal to that in the experiment. For this reason, the central processing unit11can find the pedal stroke before the decay of acoustic piano tones. In case where the magnitude of detecting signal ys does not reach the value ysH within a predetermined time period, the central processing unit11stops the experiment, and carries out the experiment at the key velocity less than the previous key velocity.

The automatic playing piano implementing the second embodiment achieves all the advantages of the first embodiment. Moreover, the experiment for the second embodiment is simpler than that for the first embodiment.

Third Embodiment

Yet another testing system implementing the third embodiment is same as the testing system60of the automatic playing piano implementing the first embodiment except for preparation of experimental data. The testing system implementing the third embodiment is incorporated in an automatic playing system, and, for this reason, component parts of the automatic playing system are accompanied with the references designating the corresponding component parts of the automatic playing piano implementing the first embodiment without detailed description.

FIG. 9shows an envelope CC of plots expressing the waveform of acoustic piano tones produced through the vibrations of the strings34. The central processing unit11correlates the magnitude of detecting signal ys with the pedal position or pedal stroke, and analyzes plots CCB in order to determines the half pedal position stH. In this instance, the central processing unit11determines a half pedal point through the following data processing instead of the jobs at steps S210and S212.

In the test, the central processing unit11pairs the pieces of loudness data expressing the magnitude of detecting signal ys with the pieces of pedal position data expressing the current pedal position. The pairs of pieces of loudness data and pieces of pedal position data are expressed by plots CCB as pieces of experimental data. The plots CCB is close to the plots CA. The plots CCB has a point of inflection pE2and a plot pS2at which the magnitude of detecting signal is deceased to zero. The point of inflection pE2and plot pS are determined as similar to pE and pS. The plots pE2and pS2express the pedal stroke stE and stS. The half pedal point stHB is determined on the line expressing the stroke difference between stE and stS through the internal division.

The testing system implementing the third embodiment achieves all the advantages of the first embodiment. Moreover, the method for specifying the half pedal point stHB is simpler than that of the first embodiment.

Fourth Embodiment

Still another testing system implementing the fourth embodiment is same as the testing system60of the automatic playing piano implementing the first embodiment except for a method of determination of a half pedal point. The testing system implementing the fourth embodiment is incorporated in an automatic playing system, and, for this reason, component parts of the automatic playing system are accompanied with the references designating the corresponding component parts of the automatic playing piano implementing the first embodiment without detailed description.

The testing system of the forth embodiment determines points of reflection stE and pS2without using the polygonal line approximation. InFIG. 10, CAD stands for a part of an envelope expressing the waveform of acoustic piano tones. The central processing unit specifies a half pedal point through a data processing shown inFIG. 11.

The central processing unit11determines the envelope CAD of the peak values as by step S301. As described hereinbefore, the magnitude of detecting signal ys is sampled at time intervals t1of 4 milliseconds, and the difference in gradient is calculated at plots A corresponding to all of the sampled points. The first plot A is 400 milliseconds later than the plot at the end position. When the central processing unit11determines the difference in gradient at a plot A, the central processing unit11specifies plots A1and A2later than the plot A by a predetermined time t2of 400 milliseconds, and determines the difference in gradient as by step S302. The difference D in gradient is stored in the random access memory13, and is expressed as follows.
D={(Magnitude of detecting signal ys atA2)−(Magnitude of detecting signal ys atA)/t2}−{(Magnitude of detecting signal ys atA)−(Magnitude of detecting signal ys atA1)/t2
Subsequently, the central processing unit11checks the random access memory13to see whether or not the difference D in gradient has been already calculated at all the plots A on the envelope CAD as by step S303. If the central processing unit11finds another plot A, the answer at step S303is given negative “No”, and the central processing unit11returns to step S302. Thus, the central processing unit11reiterates the loop consisting of steps S302to S304so that the difference D in gradient is calculated at all the plots A on the envelope CAD.

The central processing unit11finally stores the difference D in gradient at the last plot A earlier than the last sampled point by 400 milliseconds in the random access memory13. Then, the answer at step S303is changed to affirmative “Yes”, and the central processing unit11searches the random access memory13for the plot pE2at which the difference D is minimized and for another plot pS2at which the magnitude of detecting signal ys is decreased to zero as by step S305. The difference D has the maximum negative value at the plot pE2.

Finally, the central processing unit11determines the half pedal point through the internal division as similar to the job at step S104.

The testing system implementing the fourth embodiment achieves all the advantages of the first embodiment.

Fifth Embodiment

Turning toFIG. 12of the drawings, a portable testing system60E embodying the present invention is mounted on a keyboard31E of an automatic player piano. The automatic player piano includes an automatic playing system10E and a grand piano30E. Component parts of grand piano30E and System components of the automatic playing system10E are similar to those of the grand piano30and automatic playing system10. For this reason, the component parts and system components are labeled with references designating the corresponding component parts of grand piano30and corresponding system components of automatic playing system10without any detailed description for the sake of simplicity.

The portable testing system60E includes a vibration sensor51E, solenoid-operated key actuators61with built-in sensors, a solenoid-operated pedal actuator62with built-in sensor and a controlling unit63. The vibration sensor51E is same as the vibration sensor51. The number of solenoid-operated key actuators is equal to the number of black and white keys31a/31bto be moved in the test. The solenoid-operated pedal actuator62is combinable with any one of the pedals PD1, PD2and PD3.

The controlling unit63has a data processing capability, and the above-described subroutine program for specifying the half pedal point runs on the controlling unit63. When the half pedal point is determined, the controlling unit63supplies a positional data signal Dp expressing the half pedal point to the piano controller40, and the piano controller40stores the piece of pedal data expressing the half pedal point in the flash memory25.

The portable testing system60E achieves all the advantages of the first embodiment. Moreover, the portable testing system60E is combinable with the automatic player pianos without any testing system so as to make the automatic playing system10E reenact performances on the grand piano30E at high fidelity.

The subroutine program for determining the half pedal point may be supplied to the controller from an external program source through a communication network.

Moreover, an external testing system may be independent of the automatic playing system10. In this instance, the program for determining the half pedal point runs on a microprocessor in the external testing system. The external testing system is communicable with the controller of the automatic playing system10, and the pieces of test data and pieces of experimental data are transferred between the servo controller42and the external testing system.

The combination of piezoelectric element51, microphone52and electromagnetic pickup units53does not set any limit to the vibration sensor51. Any one of the three sorts of vibration-to-electric signal converters may be omitted from the combination. In case where the vibrations of acoustic piano tones are converted to the detecting signal ys through the microphone, the hammer velocity is to be increased due to a poor noise-to-signal ratio of the microphone. In case where the vibrations of acoustic piano tones are converted to the detecting signal ys through the electromagnetic pickup, it is desirable to increase the number of strings34to be struck by the hammers32in order to make the half pedal point determined through the data processing close to the half pedal point determined by a human worker. Another sort of vibration-to-electric signal converter such as a photo-interrupter may be added to the combination.

More than one piezoelectric element51and/or more than one microphone may be incorporated in the combination. In case where plural microphones52are provided over the sound board28, the plural microphones52may be spaced from one another in the lateral direction. On the other hand, plural electromagnetic pickup units53may be spaced from one another in the fore-and-aft direction.

The black and white keys31a/31bdriven at step S203may be more than three. The tones may not form any chord. Only one tone may be produced at step S203.

The strings34may be directly excited without any movement of hammers32. For example, the strings may be electromagnetically excited. In this instance, step S203is omitted from the job sequence shown inFIGS. 7A and 7B.

The central processing unit11may start the timer26when the central processing unit11instructs the pulse width modulator10bto supply the driving signal up(t) to the solenoid-operated pedal actuator26. The central processing unit11may acknowledge the movement of damper pedal PD1through the driving pulse signal up(t).

The step S101may be repeated a predetermined times. In this instance, the central processing unit11calculates the average of peak values so as to determine the envelope.

The internal division and the ratio of 2:1 do not set any limit to the technical scope of the present invention. It is possible to specify the half pedal point in the half pedal region. The half pedal point may be specified at the boundary between the restricting region and the half pedal region or the boundary between the half pedal region and the damper free region. The half pedal point stH may be determined through a simple arithmetic operation such as an addition or a subtraction. For example, the half pedal point stH may be determined at a pedal stroke spaced from the boundary between the restricting region and the half pedal region or the boundary between the half pedal region and the damper free region by a predetermined distance.

The damper pedal PD1may be moved from the rest position toward the end position. In this instance, step S202is omitted from the job sequence shown inFIGS. 7A and 7B.

The method employed in the fourth embodiment is applicable to the data processing in the third embodiment.

In the fourth embodiment, the half pedal point may be determined on the basis of only the plot pE2, and the difference D in gradient may be calculated for a part of the envelope CAD in which the central processing unit11expects the half pedal point to be found.

In the first to fourth embodiments, the central processing unit11determines the half pedal point plural times, and finally specifies the half pedal point through an appropriate arithmetic operation such as an averaging.

The uniform motion does not set any limit to the technical scope of the present invention. The damper pedal PD1may be moved in another sort of motion in so far as the pedal stroke is determinable in terms of time.

The solenoid-operated pedal actuator26is not an indispensable feature of the testing system. The pedal may be moved by means of an electric motor or supersonic motor combined with a suitable motion converter such as, for example, a pinion and rack.

The damper pedal PD1does not set any limit to the technical scope of the present invention. The testing system of the present invention may determine a half pedal point for the soft pedal PD2.

The grand piano does not set any limit to the technical scope of the present invention. The testing system of the present invention may be installed in an automatic player piano fabricated on the basis of an upright piano.

The automatic player piano does not set any limit to the technical scope of the present invention. The testing system may be installed in any sort of automatic player musical instrument in so far as manipulator of the musical instrument is changed to an intermediate position between the reset position and the end position. The testing system may be required for some sorts of automatic player wind instruments.

The subroutine program expressing the method for determining the half pedal point may be offered to users as an information storage medium in which the subroutine program has been stored. Examples of the information storage medium are a floppy disk (trademark), a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, a DVD+RW, a piece of magnetic tape, a non-volatile memory card and a memory stick. The subroutine program may be downloaded from a program source through a communication network.

In case where certain jobs in the subroutine program are accomplished through execution of a part of an operating system, the part of operating system is to be interpreted as a part of the subroutine program.

In case where the subroutine program is written in a memory of an extended board or an extended unit connected to a computer system, a microprocessor on the extended board or in the extended unit cooperates with the central processing unit of the computer system, and the microprocessor is to be interpreted as a part of the central processing unit.

The component parts and system components of the embodiments are correlated with claim languages as follows.

The acoustic piano tones are corresponding to “tones”, and the grand pianos30and30E serve as a “musical instrument”. The black keys31aand white keys31bare corresponding to “plural manipulators”, and the action units33, hammers32, strings34, sound board28, dampers36and link works71a,71band71cas a whole constitute a “tone generating system”. One of the pedals PD1, PD2and PD3serve as “another manipulator”. To prolong the tone is one of the “effects”, and to lesson the loudness of tones is another “effect”. The half pedal point stH is corresponding to a “target position”. The central processing unit11, instruction codes for the jobs at step203and the solenoid-operated key actuators20with built-in plunger sensors20cform in combination an “exciter”, and the central processing unit11, instruction codes for the jobs at steps S202and S204to S209and S211and solenoid-operated pedal actuator26with the built-in plunger position sensor27as a whole constitute a “driver”. The central processing unit11, jobs at steps S210, S102and vibration sensors51and51E serve as a “converter”, and the vibrations of sound board28, vibrations of electric motive force and compression waves of air are recognized as “vibrations expressing the tones”. The central processing unit11and instruction codes for the jobs at steps S101to S104or S301to S306as a whole constitute an “information processor”. The envelopes CA/CAA/CAD and plots CB/CCB stand for “pieces of experimental data”, and the plots pE, pS, pE2and pS2are example of “at least one point of reflection”.