Patent Grant
7405350
This invention relates to an automatic player musical instrument and, more particularly, to an automatic player musical instrument having a recording mode and a playback mode and an electronic system incorporated therein.
An automatic player piano is a typical example of the automatic player musical instrument. The automatic player piano is a combination between an acoustic piano and an electronically controlled system, and usually has two modes of operation. The first mode of operation is hereinafter referred to as “recording mode”, and the second mode is called as “playback mode”. While the automatic player piano is staying the recording mode, a user can request the electronically controlled system, which serves as a recorder, to gather pieces of music data for recording the performance on the keyboard and pedals. The recorder encodes the pieces of music data to MIDI (Musical Instrument Digital Interface) music data codes.
On the other hand, when the automatic player piano enters the playback mode, the automatic player piano gets ready to reenact the performance without any fingering of a human player. Upon reception of user's request, the electronically controlled system, which serves as an automatic player, analyzes the MIDI music data codes for reenacting the performance. The automatic player selectively depresses the black and white keys and steps on the pedals for producing the acoustic piano tones along the music passage.
The standard automatic player piano is disclosed in Japanese Patent Application laid-open No. 2001-175262 or P2001-175262A. Japanese Patent Application laid-open No. 2001-175262 was published on the basis of Japanese Patent Application No. Hei. 11-357757, the Priority Right of which had been claimed in U.S. Ser. No. 09/737,615. U.S. Ser. No. 09/737,615 was patented, and U.S. Pat. No. 6,403,872 B2 was assigned to the U.S. Patent. Hammer sensors are installed in the automatic player piano, and form parts of the recorder.
While the user is playing a piece of music on the keyboard and pedals, the hammer sensors monitor the hammers of the acoustic piano, and inform the data processor of the current hammer positions. The data processor analyzes the pieces of hammer data expressing the hammer motion so as to determine the hammer velocity, timing at which the strings are struck with the hammers and so forth and to estimate for timing at which the associated keys are depressed and released. These pieces of music data are stored in a suitable information storage medium for playback. Thus, the pieces of music data are prepared on the basis of the pieces of hammer data.
Another sort of automatic player pianos is not equipped with any hammer sensor, and is, so to speak, a “hammer sensor-less automatic player piano”. Such a hammer sensor-less automatic player piano is equipped with key sensors instead of the hammer sensors. The data processor determines the timing at which the black and white keys are depressed and released, and estimates for the hammer velocity and timing at which the strings are struck with the hammers.
The data processor determines the hammer velocity, which is defined in the MIDI protocols as “velocity” on the basis of pieces of key data supplied from the key sensors as follows. The data processor determines a measured value of the reference key velocity on the basis of the pieces of key data. The term “reference key velocity” means the key velocity at a reference key point, and is described in Japanese Patent Application laid-open No. Hei 7-175472. The reference key point is a unique point on the reference key velocity, and the value of key velocity at the reference key point is proportional to the value of hammer velocity immediately before the strike at the string. The value of hammer velocity immediately before the strike at the string is proportional to the loudness of the tone. For this reason, the value of reference key velocity is also proportional to the loudness of tone. In other words, it is possible to control the loudness of tone by adjusting the black and white key to a particular value of reference key velocity.
When the value of reference key velocity is determined on the basis of the pieces of key data, the data processor accesses a table expressing the relation between the reference key velocity and the hammer velocity, and reads out a value of hammer velocity from the table. Thus, the reference key velocity is converted to the hammer velocity, and the value of hammer velocity is encoded into the MIDI music data code expressing the note-on event.
While the automatic player is reenacting the performance expressed by a set of MIDI music data codes, the automatic player analyzes the MIDI music data codes, and determines the black and white keys to be depressed and released, loudness and the timing at which the tones are to be produced. The data processor accesses another table, which will be hereinafter described, with the loudness or a target value of hammer velocity, and reads out a corresponding value of reference key velocity from the table. When the time comes, the data processor starts to control the black and white keys through a servo-control loop so as to make the black and white key to pass the reference key point at the corresponding value of reference key velocity. This results in the target value of hammer velocity, and the tone is produced at the target loudness.
The relation between the reference key velocity and the hammer velocity is determined through an experiment carried out on a master automatic player piano by the manufacturer, and is stored in a suitable non-volatile memory of the recorder. The master automatic player piano is further equipped with the hammer sensors so that the manufacturer can determine the relation between the reference key velocity and the hammer velocity. The table, in which the relation between the reference key velocity and the hammer velocity is defined, is hereinafter referred to as “velocity conversion table”.
On the other hand, the table, in which the relation between the target values of hammer velocity and the target values of reference key velocity is stored, is hereinafter referred to as “playback table” for discriminating it from the velocity conversion table. The playback table is prepared on the basis of the velocity conversion table, and the work for preparing the playback table is hereinafter referred to as “study”.
The prior art hammer sensor-less automatic player piano studies the relation between the hammer velocity and the reference key velocity as follows: First, the data processor reads out a reference value of the reference key velocity from the information storage medium, and controls the black/white key to pass the reference key point at the reference value. When the black/white key passes the reference key point, the data processor determines a measured value of the key velocity on the basis of the pieces of key data supplied from the associated key sensor, and accesses the velocity conversion table with the measured value of the key velocity at the reference key point, i.e., the reference key velocity. The data processing unit reads out a target value of hammer velocity from the velocity conversion table, and correlates the measured value of the reference key velocity. The data processor repeats the above-described procedure at different reference values of reference key velocity, and the relation between the measured values of reference key velocity and the target values of hammer velocity is tabled as the playback table.
In short, the data processor determines the hammer velocity through the access to the velocity conversion table with the measured value of the reference key velocity in the recording mode, and correlates the measured values of reference key velocity with the read-out target values of hammer velocity through the access to the same data conversion table in the playback mode. Thus, the velocity conversion table is shared between the recorder and the automatic player.
A problem is encountered in the prior art automatic player piano in that the acoustic piano tones are produced in the playback mode at loudness smaller than that expressed in the MIDI music data codes.
It is therefore an important object of the present invention to provide an automatic player musical instrument, which faithfully reproduces acoustic tones at loudness equal to that expressed in music data codes.
It is also an important object of the present invention to provide an automatic player used in the automatic player musical instrument.
The present inventor contemplated the problem inherent in the prior art automatic player piano, and compared the original key motion, which the human player gave rise to with his or her fingers, with the reproduced key motion, which the solenoid-operated key gave rise to with its plunger. The present inventor found that the reproduced key motion was different from the original key motion. There were various differences between the original key motion and the reproduced key motion. For example, when a human player depressed a key, the key motion was close to uniformly accelerated motion as indicated by plots UA in
The present inventor concluded that the velocity conversion table was to be different between the recording and the study.
In accordance with one aspect of the present invention, there is provided an automatic player musical instrument for producing tones comprising plural manipulators selectively moved for specifying the pitch of tones to be produced, plural link works respectively connected to the plural manipulators and respectively having certain links, the motion of which are given rise to through the motion of the plural manipulators, a tone generator energized with the plural manipulators through the plural link works so as to produce the tones at the pitch specified through the plural manipulators, and an electronic system including plural sensors monitoring the plural manipulators so as to produce signals representative of the motion of the plural manipulators, plural actuators energized with driving signals so as to give rise to the motion of the plural manipulators and a data processing unit connected to the plural sensors and the plural actuators, having a converter expressing a relation between the motion of the plural manipulators and the motion of the certain links determined under the condition that the plural manipulators are moved by a human player and another converter expressing another relation between the motion of the plural manipulators and the motion of the certain links determined under the condition that the plural manipulators are moved by means of the plural actuators and estimating the motion of the certain links and the motion of the plural manipulators on the basis of pieces of data expressed by the signals and pieces of music data expressing the motion of the certain links selectively with assistance of the converter and the aforesaid another converter depending upon an origin of force exerted on the plural manipulators.
In accordance with another aspect of the present invention, there is provided an electronic system used for a musical instrument having plural manipulators, plural link works respectively connected to the plural manipulators and a tone generator energized with the plural manipulators through the plural link works for producing tones, and the electronic system comprises plural sensors monitoring the plural manipulators so as to produce signals representative of motion of the plural manipulators, plural actuators energized with driving signals so as to give rise to the motion of the plural manipulators and a data processing unit connected to the plural sensors and the plural actuators, having a converter expressing a relation between the motion of the plural manipulators and the motion of the certain links determined under the condition that the plural manipulators are moved by a human player and another converter expressing another relation between the motion of the plural manipulators and the motion of the certain links determined under the condition that the plural manipulators are moved by means of the plural actuators and estimating the motion of the certain links and the motion of the plural manipulators on the basis of pieces of data expressed by the signals and pieces of music data representative of the motion of said certain links selectively with assistance of the converter and the aforesaid another converter depending upon an origin of force exerted on the plural manipulators.
The features and advantages of the automatic player musical instrument and automatic player will be more clearly understood from the following description taken in conjunction with the accompanying drawings, in which
In the following description, term “front” is indicative of a relative position closer to a player, who is sitting on a stool for fingering, than a relative position modified with term “rear”. Term “fore-and-aft” is indicative of a direction parallel to a line drawn between a front position and a corresponding rear position, and term “lateral direction” crosses the fore-and-aft direction at right angle.
Referring to
The user plays a piece of music through fingering on the acoustic piano 100 in the standard mode, and acoustic piano tones are produced through the acoustic piano 100. Thus, the automatic player piano behaves as a standard acoustic piano in the standard mode.
When the user gives the mode instruction for the recording mode to the electronic system 300, the electronic system 300 gets ready to record performance on the acoustic piano 100. While the user is fingering on the acoustic piano 100, the electronic system 300, which serves as the recorder 301, obtains pieces of key data representative of the key motion and pieces of pedal data representative of pedal motion, and analyzes the pieces of key data and pieces of pedal data so as to produce music data codes representative of the acoustic tones produced in the performance on the acoustic piano 100. At least key numbers assigned to the depressed keys, loudness of tones to be produced and time at which the tones are to be produced are memorized in the music data codes representative of note-on events, and at least the key numbers assigned to the released keys are memorized in the music data codes representative of note-off events. The music data codes are supplied to an external data source in a real time fashion, and/or are stored in a memory. Thus, the performance on the acoustic piano 100 is recorded through the electronic system 300 in the recording mode.
On the other hand, the electronic system 300 reenacts the performance, and reproduces the acoustic piano tones through the acoustic piano 100 on the basis of a set of music data codes representative of the performance in the playback mode. The set of music data is read out from a suitable memory. Otherwise, the electronic system 300 requests an external data source (not shown) to transmit the set of music data through a cable or a public communication network. While the music data codes are sequentially being processed, the electronic system 300 determines the pitch, timing at which the acoustic piano tones are to be produced, hammer velocity or loudness, timing at which the acoustic piano tones are to be decayed and effects to be imparted to the acoustic piano tones, if any, along the music passage, and plays the music passage on the acoustic piano 100 without any fingering of a human player.
As will be hereinafter described in detail, two sorts of velocity conversion tables are stored in the electronic system 300. One of the velocity conversion table is used in the recording mode, and is hereinafter referred to as “velocity conversion table for fingered keys”. The other velocity conversion table is used in the playback mode, and is hereinafter referred to as “velocity conversion table for solenoid-actuated keys”. The velocity conversion table for fingered keys is optimized to the key motion in the recording mode, and the velocity conversion table for solenoid-actuated keys is optimized to the key motion in the playback mode. Thus, the automatic player determines a target value of the hammer velocity through the access to the velocity conversion tables depending upon the mode of operation. This results in a faithful reenactment of a performance.
The velocity conversion table for fingered keys and velocity conversion table for solenoid-actuated keys are prepared by a manufacturer through experiments. The experiments are carried out on a master automatic player piano. The master automatic player piano is similar to the automatic player piano shown in
Both hammer and key velocities are determined in the master automatic player piano on the basis of the key position signals, which are output from the key sensors and hammer position signals, which are output through hammer sensors. The hammer sensors monitor final parts of the hammer trajectories immediately before the strings 4. Thus, the velocity conversion table for fingered keys and velocity conversion table for solenoid-actuated keys express the relation between measured values of the reference key velocity, which are determined on the basis of the actual key motion, and measured values of the hammer velocity, which are also determined on the basis of the actual hammer motion.
The acoustic piano 100 includes a keyboard 1, action units 2, hammers 3, strings 4 and dampers 5. The keyboard 1 is mounted on a front portion of a key bed 102, which defines the bottom of a piano cabinet, and the action units 2, hammers 3, strings 4 and dampers 5 are housed in the piano cabinet.
An array of black keys 1a and white keys 1b is incorporated in the key-board 1. The black keys 1a and white keys 1b are elongated in the fore-and-aft direction, and are laterally laid on the well-known pattern. In this instance, eighty-eight black and white keys 1a/1b form the array. The black keys 1a and white keys 1b pitch on a balance rail 104, and balance pins P keep the black keys 1a and white keys 1b on the balance rail 104. Front pins guide the black keys 1a and white keys 1b toward a front rail 106 so that the front portions of black keys 1a and front portions of white keys 1b reciprocally travel on predetermined trajectories.
The black and white keys 1a/1b are staying at respective rest positions without any external force exerted on the front portions thereof. The rest positions are located at stroke of zero, and the black keys 1a and white keys 1b at the rest positions are drawn by real lines in
The black and white keys 1a/1b are respectively linked at the rear portions thereof with the action units 2, and the action units 2 give rise to free rotation of the hammers 3. The strings 4 are stretched over the hammers 3, and dampers 5 are linked with the rearmost portion of the black and white keys 1a/1b so as to be spaced from and brought into contact with the strings 4.
While the black and white keys 1a/1b are staying at the rest positions, the hammers 3 are held in contact at hammer rollers 3a thereof with the heads of jacks 2a, which form parts of the action units 2, and the dampers 5 are held in contact with the strings 4 as shown in
When the jack 2a escapes from the hammer roller 3a, the hammer 3 starts the free rotation toward the string 4. The hammer 3 is brought into collision with the string 4 at the end of the free rotation, and gives rise to the vibration of the string 4. The string vibrations give rise to the acoustic piano tone at the given pitch.
The hammer 3 rebound on the string 4, and is received by the action unit 2. When the pianist releases the depressed key 1a/1b, the released key 1a/1b starts to return toward the rest position. The damper 5 is brought into contact with the vibrating string 4 on the way of the released key 1a/1b toward the rest position so that the acoustic piano tone is decayed. When the released key 1a/1b arrives at the rest position, the action unit 2 and hammer 3 return to their rest positions as shown in
The electronic system 300 serves as the recorder 301 in the recording mode and the automatic player 302 in the playback mode as described herein-before. The function of the recorder 301 is broken down into a recording controller 12 and a post data processor 13. On the other hand, the function of the automatic player 302 is broken down into a preliminary data processor 10 and a motion controller 11. The recording controller 12, post data processor 13, preliminary data processor 10 and a motion controller 11 are realized through a computer program running on a data processing unit 303, the system configuration of which will be hereinlater described with reference to
The electronic system 300 further includes an array of solenoid-operated key actuators 6, an array of key sensors 7, solenoid-operated pedal actuators (not shown) and pedal sensors (not shown). The plungers and solenoids are labeled with references 8a and 8b, respectively. A slot is formed in the key bed 102 under the rear portions of the black and white keys 1a/1b, and is laterally elongated. The solenoid-operated key actuators 6 are hung from the key bed 102, and are laterally arrayed under the rear portions of the black/white keys 1a/1b. The solenoids 8b are disposed in the slot, and the data processing unit 303 is connected to the solenoids 8b. The plungers 8a are upwardly directed, and the tips of plungers 8a are in the proximity of the lower surfaces of the rear portions of the associated black and white keys 1a/1b. When the data processing unit 303 determines a key 1a/1b to be moved, the data processing unit 303 supplies a driving pulse signal u to the solenoid 8b associated with the key 1a/1b. Then, the solenoid 8b creates magnetic field, and the magnetic force is exerted on the plunger 8a in the magnetic field. The plunger 8a upwardly projects from the solenoid 8b, and pushes the rear portion of the key 1a/1b so as to give rise to the key motion.
The key sensors 7 are of the type radiating light beams across the trajectories of the front portions of the black and white keys 1a/1b. In other words, the key sensors 7 are implemented by non-contact optical sensors. The key sensors 7 are arrayed on the key bed 102 in the lateral direction, and are operative to convert current key positions on the trajectories to analog key position signals yxa. Since the key trajectories between the rest positions and the end positions are fallen within the cross sections of the light beams, it is possible continuously to express the current key positions between the rest positions and the end positions in the key position signals yxa. The current key position is equivalent to the stroke from the rest position. In this instance, the end positions are spaced from the corresponding rest positions by 10 millimeters. Accordingly, the current key position has a value varied from zero to 10 in millimeter.
The key position signals yxa are supplied to the recording controller 12 in the recording mode and to the motion controller 11 in the playback mode. While the electronic system 300 is serving as the recorder 301, the recording controller 12 analyzes the pieces of key data expressed by the key position signals yxa so as to determine the key motion, supplies the pieces of music data, which express the performance, to the post data processor 13, and the post data processor 13 encodes the pieces of normalized music data in the formats defined in the MIDI protocols. In the normalization process, the post data processor 13 eliminates noise components due to the individualities of the acoustic piano 100 and individuality of key sensors 7 from the pieces of music data.
On the other hand, while the electronic system 300 is serving as the automatic player 302, the preliminary data processor 10 analyzes the music data codes so as to determine the reference key velocity, reference trajectories for the black keys 1a and white keys 1b to be moved, and the motion controller 11 compares the current key positions and current key velocity, which is calculated on the basis of the pieces of key data, with target key positions on the reference trajectories and target key velocity to see whether or not the black keys 1a and white keys 1b are exactly traveling on the reference trajectories. If the black keys 1a and white keys 1b are deviated from the reference trajectories, the motion controller 11 varies the mean current or duty ratio of the driving pulse signal u so as to force the black keys 1a and white keys 1b timely to catch up the next target key position on the reference trajectories. The black/white keys 1a/1b travelling on the reference trajectories give the hammer velocity expressed in the music data codes to the hammers 3. Thus, the key position signals yxa are used in a servo control on the solenoid-operated key actuators 6. In this instance, the solenoid-operated key actuators 6, key sensors 7 and motion controller 11 as a whole constitute a servo-control loop.
The current key velocity is determinable through the differentiation on a function expressing a series of current key positions. In a practical use, two reference points are determined on each of the key trajectories, and the current key velocity is given as a mean velocity in millimeter/second.
Turning to
A microprocessor may serve as the central processing unit 20. A computer program, which includes a main routine program and subroutine programs, and parameter tables are stored in the read only memory 21 together with the velocity conversion table for fingered keys, velocity conversion table for solenoid-actuated keys, a reference table and a timing table for tone generation, and the random access memory 22 serves as a working memory. The random access memory 22 offers a temporary data storage to the central processing unit 20, and the playback table is prepared in the random access memory 22 through data transfer from the data storage 23. The timing table for tone generation expresses a relation between the hammer velocity and the timing at which the strings 4 are struck with the hammers 3.
The velocity conversion table for solenoid-actuated keys and velocity conversion table for fingered keys are hereinafter described with reference to figures 4A and 4B. The velocity conversion table for solenoid-actuated keys and velocity conversion table for fingered keys are respectively designated by reference numerals 30 and 31. The hammer velocity is corresponding to the “velocity” defined in the MIDI protocols, and the target value of “velocity” is assumed to be varied from zero to 80 for the sake of simplicity.
Pieces of key data and pieces of hammer data were gathered in the master automatic player piano, and were analyzed as follows. A human operator depressed a key of the master automatic player piano. The key sensor supplied pieces of key data representative of the current key position, and the hammer sensor supplied pieces of hammer data representative of the current hammer position or hammer motion, which the depressed key gave rise to. The data processor calculated the reference key velocity on the basis of the pieces of key data around the reference key point, and further calculated the hammer velocity on the basis of the pieces of hammer data immediately before the strike at the string. The calculation results were indicative of a measured value of reference key velocity and a measured value of hammer velocity, and the measured value of reference key velocity was correlated with the measured value of hammer velocity.
The human operator repeated the above-described experiment at different values of force for each of the black and white keys. Upon completion of the experiment, a set of measured values of hammer velocity was correlated with a set of measured values of reference key velocity, and the relation between the measured values of reference key velocity and the measured values of hammer velocity was memorized in the velocity conversion table 31 for fingered keys.
Subsequently, the human operator instructed the electronic system of the master automatic player piano to drive the black and white keys at a reference value of reference key velocity, and gathered the pieces of key data and pieces of hammer data through the key sensors and hammer, sensors for the black and white keys. The data processor calculated the reference key velocity on the basis of the pieces of key data around the reference key points, and further calculated the hammer velocity on the basis of the pieces of hammer data immediately before the strikes at the string. The calculation results were indicative of measured values of reference key velocity and measured values of hammer velocity. Thus, the measured values of reference key velocity were correlated with the measured values of hammer velocity through the experiment and calculation. The operator repeated the experiment at different reference values of reference key velocity, and the measured values of reference key velocity were correlated with the measured values of hammer velocity in the velocity conversion table 30 for solenoid-actuated keys.
Plots PL1 and PL2 stand for the relation between the hammer velocity and the reference key velocity stored in the velocity conversion table 30 for solenoid-actuated keys and velocity conversion table 31 for fingered keys, respectively. Comparing plots PL1 with plots PL2, it is understood that the black/white keys 1a/1b, which a human player depressed with his or her fingers, gave rise to the hammer motion higher in reference key velocity than the hammer motion given rise to by the solenoid-operated key actuators 6. For example, when the black/white key 1a/1b was moved at 0.2 ml/s, the solenoid-operated key actuator 6 gave rise to the hammer motion at 60 in MIDI code through the key motion, and the human player gave rise to the hammer motion at 70 in MIDI code through the same key motion.
Although the tables are stored in the read only memory 21 in the non-volatile manner in the electronic system 300, the tables may be stored in the non-volatile data storage 23 so as to be transferred to the random access memory 22 through a system initialization in the main routine program. While electric power is being supplied to the data processing unit 303, the central processing unit 20 reiterates the main routine program in order to communicate with users, and the main routine program selectively branches into subroutine programs depending upon user's instruction.
Turning back to
The interface 24 includes analog-to-digital converters, and the key sensors 7 are connected to the analog-to-digital converters. The key position signals yxa are supplied to the analog-to-digital converters, and are converted to digital key position signals. The central processing unit 20 periodically fetches the pieces of key data expressed by the digital key position signals, and memorizes the pieces of key data in the random access memory 22. A software timer gives the timing at which the key data is fetched to the central processing unit 20. The central processing unit 20 analyzes the series of key data so as to determine the current key status for each of the black and white keys 1a/1b.
The pulse width modulator 25 is responsive to a control signal, which is supplied from the central processing unit 20, so as to adjust the driving pulse signal u to a target value of mean current or a given duty ratio, and supplies the driving signal u to the solenoid 8b for the black/white key 1a/1b to be actuated.
Although other system components such as a switches, indicators and display window are not shown in
When a user instructs the electronic system 300 to record his or her performance, the main routine program branches to a subroutine program for the recording, and the subroutine program runs on the central processing unit 20 for recording the performance.
Firstly, the central processing unit 20 sets an index register kn for “1” as by step S1. The index register kn is indicative of the key number assigned to the black key 1a or white key 1b, and the value stored therein is varied between 1 and 88. The key number “1” is assigned to leftmost white key 1b. The central processing unit 20 periodically reiterates the loop consisting of steps S1 to S9 in the recording mode so as to find black and white keys 1a/1b moved by the human player.
The central processing unit 20 compares the latest value of current key position with the previous value of current key position and the thresholds K1 and K2 to see whether or not the white key 1b proceeds to the next zone Z2 or Z3 as by step S2. In this instance, each of the key trajectories is divided into three zones Z1, Z2 and Z3 as shown in
Turning back to
When the central processing unit 20 investigated the eighty-eighth key 1b, the answer at step S9 is changed to affirmative, and the central processing unit 20 returns to step S1. The central processing unit 20 resets the index register kn to 1, and investigates the leftmost white key 1b, again.
Thus, the central processing unit 20 reiterates the loop consisting of steps S1, S2, S8 and S9, and looks for a black key/white key 1a/1b entering the next zone Z2 or Z3 across the threshold K1 or K2.
The central processing unit 20 is assumed to find a black/white key 1a/1b entering the next zone Z2 or Z3. The answer at step S2 is changed to the affirmative “Yes”, and the central processing unit 20 checks the comparison result to see whether the black/white key 1a/1b proceeds from the zone Z1 to the zone Z2 or from the zone Z2 to the zone Z3 as by step S3. When the black/white key 1a/1b entered the zone Z2, the central processing unit 20 adopts course “A”, and checks the software timer for determining the time so as to memorize the time together with the key position in the random access memory 22 as by step S4. Upon completion of the jobs at step S4, the central processing unit 20 proceeds to step S8. Thus, the central processing unit 20 returns to the loop. The current key position and time are used in step S2 in the next execution.
If, on the other hand, the black/white key 1a/1b entered the next zone Z3, the central processing unit 20 acknowledges that the black/white key 1a/1b have given rise to the free rotation of the hammer 3, and adopts course “B”. The course “B” leads the central processing unit 20 to step S5, and the central processing unit 20 determines the reference key velocity. The difference in length, i.e., (n−m) is divided by the difference between the transit time at threshold K1 and the transit time at threshold K2, and the quotient represents the reference key velocity.
Subsequently, the central processing unit 20 accesses the velocity conversion table for fingered keys 31, and reads out a target value of hammer velocity corresponding to the measured value of reference key velocity as by step S6. Upon completion of the jobs at step S6, the central processing unit 20 proceeds to step S7, and accesses the timing table for tone generation so as to determine the timing to produce the acoustic piano tone. Pieces of timing data are correlated with the values of hammer velocity in the timing table for tone generation. The timing data is indicative of a lapse of time from the transit at K2 to the initiation of tone generation, and the unit is millisecond.
The central processing unit 20 makes pieces of hammer data representative of the values of hammer velocity Velo 1, Velo 2, Velo 3, . . . . Velo 16 paired with the pieces of timing data T1, T2, T3, . . . and T16 as shown in
Upon completion of the memorization, the central processing unit 20 returns to the loop consisting of steps S1, S2, S8 and S9. Thus, the central processing unit 20 reiterates the loop consisting of steps S1 to S9 so as to obtain the pieces of music data.
Though not shown in
As described hereinbefore, the central processing unit 20 repeatedly executes the program sequence shown in
Thus, the central processing unit 20 estimates the hammer velocity by using the velocity conversion table 31 for fingered keys, and produces the MIDI music data codes representative of the performance.
The timing to generate the acoustic tones is controlled through a count-down subroutine shown in
While the main routine program or subroutine program is running on the central processing unit 20, the timer interruption is assumed to takes place. The main routine program or subroutine program branches to the count-down subroutine. The central processing unit 20 firstly accesses the random access memory 22, and reads out each of the pieces of time data T1, T2, . . . , which “T” stands for in
Subsequently, the central processing unit 20 checks the pieces of timing data T to see whether or not any one of the values reaches zero as by step S11. If the answer is given negative “no”, the central processing unit 20 immediately returns to the main routine program or subroutine program.
On the other hand, when the central processing unit 20 finds one of the pieces of timing data T is indicative of zero, the answer at step S11 is given affirmative “yes”. Then, the central processing unit 20 supplies the associated piece of hammer data to a suitable destination as by step S12. If the user wishes to produce electronic tones through another electronic musical instrument (not shown), the central processing unit 20 outputs a music data code, in which the piece of hammer data is stored, through the interface 24 to the electronic musical instrument (not shown). If, on the other hand, the electronic system 300 further includes an electronic tone generator (not shown) and a sound system (not shown), the central processing unit 20 supplies the music data code to the electronic tone generator (not shown), and the electronic tone generator (not shown) starts to compose an audio signal. Another candidate of the destination is the data storage 23. The music data codes may be stored in the data storage 23 together with or without duration data codes.
Upon completion of the jobs at step S12, the central processing unit 20 returns to the main routine program or subroutine program. Thus, the central processing unit 20 controls the timing to produce the tones with the pieces of timing data.
In the playback, the solenoid-operated key actuators 6 give rise to the hammer motion through the key motion. Although target values of hammer velocity is memorized in the music data codes expressing the note-on events, the solenoid-operated key actuators 6 can not directly move the hammers 3, but exert the force on the black and white keys 1a/1b so as to give rise to the key motion. The force is varied with the mean current of the driving pulse signal u. The larger the force is, the larger the key velocity is.
The data processing unit 303 is expected to control the hammer motion with the driving pulse signal through the key motion. The data processing unit 303 determines a target value of reference key velocity through the access to the playback table, and controls the key motion through the servo-control loop with the driving pulse signal. The playback table is prepared through the study, and
Assuming now that a user turns on the power switch as by step S20, the main routine program starts to run on the central processing unit 20, and firstly initializes the electronic system 300. If the user instructs the central processing unit 20 to prepare the playback table, the central processing unit 20 acknowledges the user's instruction as by step S21, and determines a critical value of the mean current at which the hammer is driven for the free rotation as by steps S22 and S23. The user gives the instruction at step S21 to the central processing unit 20 when the workers complete a repairing work or a maintenance work on the automatic player piano.
In detail, the central processing unit 20 instructs the servo-control loop to adjust the black/white key 1a/1b to the minimum target value of reference key velocity. The pulse width modulator 25 starts to supply the driving pulse signal u to the solenoid 8b of the associated solenoid-operated key actuator 6, and the central processing unit 20 checks the piece of key data to see whether or not the black/white key 1a/1b exactly travels on the reference trajectory. The servo-control loop keeps, increases or decreases the mean current of the driving pulse signal u in order to make the black/white key 1a/1b pass the reference point at the minimum target value.
If the plunger 8b exerts the force, which is large enough to make the hammer 3 escape from the jack 2a, on the rear portion of the black/white key 1a/1b, the hammer 3 starts the free rotation, and the string 4 is struck with the hammer 3. The string 4 generates the acoustic piano tone. If, on the other hand, the force is too small, the hammer 3 can not escape from the jack 2a, and any acoustic piano tone is not generated. The central processing unit 20 presumes the string 4 to be struck with the hammer 3 on the basis of the key position. As will be described in conjunction with
With the negative answer “No” at step S23, the central processing unit 20 returns to step S22, and instructs the servo-control loop to make the black/white key 1a/1b pass the reference point at the next target value of reference key velocity. The next target value is greater than the minimum target value. The pulse width modulator 25 increments, decrements and keeps the mean current of the driving signal so that the servo-control loop makes the black/white key 1a/1b pass the reference key point at the next target value of reference key velocity. Thus, the central processing unit 20 reiterates the loop consisting of steps S22 and S23 until the answer at step S23 is changed to affirmative.
The hammer 3 is assumed to escape from the jack 2a at a certain target value of reference key velocity. The answer at step S23 is changed to affirmative. With the positive answer “Yes”, the central processing unit 20 proceeds to step S24, and decides that the certain target value is the critical value of reference key velocity. The minimum value of velocity defined in the MIDI message has been already known. Then, the central processing unit 20 correlates the critical target value of reference key velocity with the minimum value of velocity, which is corresponding to the minimum value of the hammer velocity.
Upon completion of the job at step S24, the central processing unit 20 enters a subroutine program for the study as by step S25. The sequence of the subroutine program is shown in
Upon entry into the subroutine program for the study, the central processing unit 20 increments the target value of reference key velocity as by step S30. In the first execution at step S25, the reference key velocity is increased from the certain target value, which is corresponding to the critical value, to the next value. It is not necessary that the increment is corresponding to the value of the highest resolution. The hammer velocity may be stepwise increased five times between the minimum value and the critical value F (see
The servo-control loop controls the black/white key 1a/1b to pass the reference key point at the next value. The pulse width modulator 25 increases, decreases and keeps the driving pulse signal u, and supplies the driving pulse signal u to the solenoid 8b. The plunger 8a upwardly pushes the rear portion of the black/white key 1a/1b, and gives rise to the key motion. The force is sequentially transmitted from the black/white key 1a/1b through the action unit 2 to the hammer 3, and the string 4 is struck with the hammer 3 at the end of the free rotation.
In this situation, the key sensor 7 reports the key motion to the central processing unit 20 through the key position signal yxa, and the central processing unit 20 determines the reference key velocity as by step S31. With the measured value of reference key velocity, the central processing unit 20 accesses the velocity conversion table 30 for solenoid-actuated keys, and reads out the corresponding value of the hammer velocity from the velocity conversion table 30 for solenoid-actuated keys as by step S32. The corresponding value is interpreted as a target value of hammer velocity. The central processing unit 20 correlates the target value of hammer velocity with the measured value of reference key velocity, and stores them in the random access memory 22. The jobs at step S32 will be hereinlater described in more detail.
Subsequently, the central processing unit 20 compares the target value of hammer velocity with the critical value F to see whether or not the study work reaches the boundary between a low-and-medium speed part and a high-speed part as by step S33. While the answer at step S33 is given negative “No”, the central processing unit 20 reiterates the loop consisting of steps S30 to S33, and accumulates the target values of hammer velocity correlated with the measured values of reference key velocity in the random access memory 22.
When the central processing unit 20 finds the target value of hammer velocity approximately equal to the critical value F, the central processing unit 20 completes the “study”, and determines the low-to-medium speed part as by step S34, and stores the relation in the low-to-medium speed part in the random access memory 22. Thereafter, the central processing unit 20 returns to the subroutine program shown in
Turning back to
The manufacturer prepares the reference table through experiments on the master automatic player piano before the delivery to the user. The manufacturer instructs the data processing unit of the master automatic player piano to make the black/white key pass the reference point at a reference value of reference key velocity through the servo-control loop. The driving signal is supplied from the pulse width modulator to the solenoid-operated key actuators, and the mean current is increased, decreased and maintained in order to make the black/white keys pass the reference key points at the reference value. The actuated black/white keys give rise to the hammer motion. The hammer sensors supply the hammer position signal to the data processing unit, and the data processing unit determines the hammer velocity on the basis of the pieces of hammer data. The data processing unit correlates the measured value of the hammer velocity with the reference value of reference key velocity.
Even if the solenoid-operated key actuators 6 make the key motion unstable, the hammer velocity is directly determined on the basis of the pieces of hammer data so that the relation in the reference table is reliable. The experiment is repeated at different reference values of the reference key velocity, and the relation between the reference values of reference key velocity and the measured values of the hammer velocity is memorized in the reference table. Thus, the reference table is prepared through the experiments, and is duplicated into the suitable memory such as the read only memory 21.
The central processing unit 20 transcribes the high-speed part H from the read only memory 21 to the random access memory 22, and merges the high-speed part H with the low-to-medium speed part ML as by step S27. Thus, the central processing unit 20 completes plots PL11 (see
Although the low-to-medium speed part is tailor-made, the high-speed part is merely transcribed from the reference table to the playback table, and the reference table is ready-made for the products of the hammer sensor-less automatic player piano. It may be rare that the rightmost value on the low-to-medium speed part ML is equal to the leftmost value of the high-speed part H. This means that the low-to-medium speed part ML has to be connected to the high-speed part H through a suitable merging technique.
There are some candidates. The first candidate is the interpolation. Values are interpolated between the rightmost value “P” (see
The central processing unit 20 repeats the above-described sequence eighty-eight times, and completes the playback table 21a for the eighty-eight keys 1a/1b as shown in
As will be understood, the playback table 21a is partially prepared through the study, and is merged between the relation determined through the study and the transcription of the part H from the reference table. The reference table is prepared through the experiments on the master automatic player piano, and the influence of unstable key motion is taken into account. In other words, the servo-control loop is expected to give rise to the hammer motion in the relation between the reference key velocity and the hammer velocity. Thus, the playback table according to the present invention makes the original hammer motion exactly reproduced in the playback mode.
The central processing unit 20 reads out the latest two values of the key data for the leftmost key 1b from the random access memory 22, and compares the latest value of current key position with the previous value of current key position and the thresholds K1 and K2 to see whether or not the white key 1b proceeds to the next zone Z2 or Z3 as by step S41. If the white key 1b still stays in the zone Z1, Z2 or Z3 from the previous execution to the present execution, the answer is given negative “No”. With the negative answer “No”, the central processing unit 20 increments the key number kn by one as by step S47, and compares the key number kn with 88 to see whether or not the key number kn is greater than 88 as by step S48. While the central processing unit 20 is investigating the leftmost white key 1b and the right-most white key 1b, the answer at step S48 is given negative “No”, and the central processing unit 20 returns to step S41.
When the central processing unit investigated the eighty-eighth key 1b, the answer at step S48 is changed to affirmative, and the central processing unit 20 returns to step S40, and resets the index register kn to 1.
Thus, the central processing unit 20 reiterates the loop consisting of steps S40, S47 and S48, and looks for a black key/white key 1a/1b entering the next zone Z2 or Z3 across the threshold K1 or K2.
The central processing unit 20 is assumed to find that the white key 1b enters the next zone Z2 or Z3. The answer at step S41 is changed to the affirmative “Yes”, and the central processing unit 20 checks the comparison result to see whether the white key 1b proceeds from the zone Z1 to the zone Z2 or from the zone Z2 to the zone Z3 as by step S42. When the white key 1b entered the zone Z2, the central processing unit 20 adopts course “A”, and checks the software timer for determining the present time so as to memorize the present time together with the latest value of the key position in the random access memory 22 as by step S43. Upon completion of the jobs at step S43, the central processing unit 20 proceeds to step S47, and returns to the loop. The latest value of the current key position is used in steps S41 and S44 in the next execution.
If, on the other hand, the white key 1b entered the next zone Z3, the central processing unit 20 acknowledges that the black/white key 1a/1b have given rise to the free rotation of the hammer 3, and adopts course “B”. The course “B” leads the central processing unit 20 to step S44, and the central processing unit 20 determines the reference key velocity.
In detail, the central processing unit 20 determines the latest value of the current key position and the present time, and respectively subtracts the latest value of current key position and the present time from the previous value and previous time, which were memorized at step S43 in the previous execution. The difference between the values of current key position is divided by the difference between the previous time and the present time, and determines the mean value of the key velocity.
Subsequently, the central processing unit 20 accesses the velocity conversion table 30 for solenoid-actuated keys, and reads out a value of hammer velocity corresponding to the mean value of the key velocity as by step S45. Thus, the measured value of reference key velocity is correlated with the read-out target value of hammer velocity.
Upon completion of the jobs at step S45, the central processing unit 20 proceeds to step S46, and accesses the timing table for tone generation so as to determine the timing to generate the tone. Thereafter, the central processing unit 20 returns to the loop. Thus, the central processing unit 20 reiterates the loop consisting of steps S40 to S48 so as to correlate the key velocity with the hammer velocity with reference to the velocity conversion table 30 for the solenoid-actuated keys.
As will be understood, the two velocity conversion tables 30 and 31 are selectively used depending upon the origin of the force exerted on the black and white keys 1a/1b. This results in the playback table exactly defined for the playback and a set of music data codes exactly expressing the performance on the keyboard 1.
Assuming now that a user instructs the electronic system 300 to reenact his or her performance, the central processing unit 20 transfers the set of music data codes representative of the performance from the data storage 23 to the random access memory 22, and sequentially reads out the music data codes from the random access memory 23. The music data codes express note-on events, note-off events, lapse of time between the previous note-on event/previous note-off event and the note-on event/note-off event and other messages.
When the central processing unit 20 receives the music data code expressing the note-on event, the central processing unit 20 determines the black/white key 1a/1b to be actuated, timing at which the black/white key 1a/1b starts toward the end position, a target value of the reference key velocity and the reference trajectory for the black/white key 1a/1b. The function is expressed as “preliminary data processor” in
When the central processing unit 20 determines the reference trajectory through the function as the preliminary data processor 10, the servo-control loop starts to control the black/white key 1a/1b pass the reference key point at the target value of reference key velocity.
When the driving pulse signal u flows through the solenoid 8b, the solenoid 8b creates the magnetic field, and the magnetic force, which is proportional to the value of mean current, is exerted on the plunger 8a. The plunger 8a upwardly projects from the solenoid 8b, and pushes the rear portion of the black/white key 1a/1b. The front portion of the black/white key 1a/1b is slightly sunk, and the key sensor 7 reports the current key position to the data processor 20 through the key position signal yxa.
The central processing unit 20 compares the target value of the key position on the reference key trajectory with the measured value of the current key position to see whether or not the black/white key 1a/1b exactly travels on the reference trajectory. If the answer is given affirmative, the central processing unit 20 requests the pulse width modulator 25 to keep the driving pulse signal u at the value of the mean current. If, on the other hand, the answer is given negative, the central processing unit 20 determines a new value of the mean current to be required for bringing the black/white key 1a/1b to the next value of the key position on the reference trajectory, and informs the pulse width modulator 25 of the new value of mean current. Thus, the central processing unit 20, pulse width modulator 25, solenoid-operated key actuator 6 and key sensor 7 serve as the servo control loop.
While the black/white key 1a/1b is traveling on the reference key trajectory, the servo-control loop requests the pulse width modulator 25 to increase, decrease and keep the mean current of driving pulse signal u as described hereinbefore so that the black/white key 1a/1b passes the reference key point at the target value of reference key trajectory.
The central processing unit 20 repeats the above-described control sequence for the black/white keys 1a/1b to be actuated so that the acoustic piano tones are sequentially produced along the music passage without any fingering of a human pianist.
The central processing unit 20 fetches the MIDI music data code to be firstly processed from the random access memory 22, and specifies the black/white key 1a/1b to be moved, the hammer velocity or loudness and the timing to produce the tone as by step S51.
Subsequently, the central processing unit 20 accesses a data block 2101 to 2188 of the playback table 21a corresponding to the black/white key 1a/1b to be moved, and reads out a target value of the reference key velocity corresponding to the target value of hammer velocity indicative of the target loudness as by step S52. The central processing unit 20 determines a reference trajectory for the black/white key 1a/1b. The pulse width modulator 25 starts to supply the driving pulse signal u to the solenoid-operated key actuator 6 associated with the black/white key 1a/1b to be moved.
The driving pulse signal u causes the plunger 8a to project so as to give rise to the key motion. While the plunger 8a is projecting upwardly, the key sensor 7 reports the current key position to the central processing unit 20, and the central processing unit 20 compares the current key position with the target key position on the reference trajectory to see whether or not the black/white key 1a/1b exactly travels on the reference trajectory. If the answer is given affirmative, the central processing unit 20 instructs the pulse width modulator 25 to keep the mean current of the driving pulse signal u at the present value. On the other hand, if the answer is given negative, the central processing unit 20 instructs the pulse width modulator 25 to increment or decrement the mean current, and the pulse width modulator 25 varies the mean current of the driving pulse signal u. Thus, the servo-control loop forces the black/white key 1a/1b to pass the reference key point at the target value of reference key velocity as by step S53.
Subsequently, the central processing unit 20 checks the random access memory 22 to see whether or not a MIDI music data code representative of the event is still left therein as by step S54. When the central processing unit 20 finds the MIDI music data code in the random access memory, the answer is given negative “No”, and the central processing unit 20 returns to step S51. Thus, the central processing unit 20 reiterates the loop consisting of steps S51 to S54 for processing the MIDI music data codes. If the central processing unit 20 does not find any MIDI music data code, the answer at step S54 is given affirmative, and the central processing unit 20 returns to the main routine program.
As will be appreciated from the foregoing description, the two sorts of velocity conversion tables 30 and 31 have been prepared for the recording and study, and are stored in the data processing unit 303 before delivery to the user. While the recorder 301 is recording the performance on the keyboard 1, the data processing unit 303 determines the loudness of tones or hammer velocity through the access to the velocity conversion table 31 for fingered keys. Since the data conversion table 31 for fingered keys expresses the relation between the hammer velocity and the reference key velocity determined through the experiment on the master automatic player piano, the data processing unit 303 can exactly determine the hammer motion with reference to the velocity conversion table 31 for fingered keys so that the performance is recorded as a set of music data codes.
On the other hand, while the data processing unit 303 is preparing the playback table 21a, the solenoid-operated key actuators 8 sequentially give rise to the key motion, and the data processing unit 303 determines the hammer velocity through the access to the velocity conversion table 30 for solenoid-actuated keys. Since the data conversion table 30 for solenoid-operated keys expresses the relation between the hammer velocity and the reference key velocity for the keys actuated by the solenoid-operated key actuators in the master automatic player piano, the unstable key motion is taken into account so that the data processing unit 303 exactly estimates the hammer velocity on the basis of the key velocity. Thus, the automatic player piano according to the present invention exactly records and reenacts the performance through the selectively access to the two velocity conversion tables 30 and 31.
Although the particular embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.
For example, the relations between the key velocity and hammer velocity shown in
In the above-described embodiment, the loudness of tones is expressed as the hammer velocity. However, the loudness may be expressed as motion of another component part such as, for example, the jack 2a. Thus, the hammer and hammer velocity do not set any limit to the technical scope of the present invention.
The non-contact optical sensors may be replaced with another sort of sensor such as, for example, a magnetic sensor or a potentiometer. The other sort of sensor may convert velocity or acceleration of the black/white keys 1a/1b to key velocity signals or key acceleration signals. The position, velocity and acceleration are converted to one another through the differentiation and integration. The functions 12/13 of recorder 301 and functions 10/11 of automatic player may be realized by means of wired logic circuits.
A flexible disk driver unit, a floppy disk (trademark) driver unit, a compact disk driver unit, a photo-electro-magnetic disk driver unit, a ZIP disk driver unit and a DVD (Digital Versatile Disk) driver unit are available for the data storage 23. In case where the tables are stored in the read only memory 21, a RAM board is available for the data storage 23.
Another automatic player according to the present invention may have an equation or a set of equations expressing the relation between the hammer velocity and the key velocity.
The read only memory 21 may be implemented by electrically erasable programmable read only memory. In this instance, the read only memory 21 can partially serve as a working memory.
The reference tables may be replaced with only one reference table or some reference tables. The some reference tables may be assigned to different pitched parts. In case where only one reference table is shared among all the black and white keys 1a/1b, only one high-speed part may be accessed for all the black and white keys 1a/1b. In this instance, only a small amount of memory space is occupied by the playback tables so that the manufacturer can reduce the data holding capacity of the random access memory 22.
In the above-described embodiment, the keys are assumed to take the uniform motion. The black/white keys 1a/1b may be assumed to take a uniformly accelerated motion. Even if the black/white keys are assumed to take the uniformly accelerated motion, the reference trajectories are presumable for the keys to be moved, and the solenoid-operated key actuators give rise to the key motion with reference to the playback table.
The acceleration and/or displacement may be taken into account in the servo-control. In this instance, the servo-control is carried out on selected one of ones of the position, velocity and acceleration.
The MIDI protocols do not set any limit to the technical scope of the present invention. Even if an automatic player musical instrument is designed on the basis of another set of musical protocols, the present invention is applicable to the automatic player musical instrument in so far as the loudness of tones are to be controlled on the basis of certain behavior of component parts not directly monitored.
The automatic player piano does not set any limit to the technical scope of the present invention. The present invention is applicable to any sort of automatic player musical instrument fabricated on the basis of another acoustic or hybrid musical instrument such as, for example, a mute piano, a keyboard for practical use, a harpsichord or a celesta. The mute piano is a hybrid keyboard musical instrument, and a hammer stopper and an electronic tone generator are installed in an acoustic piano. While a pianist is performing a piece of music on the mute piano without any acoustic piano tones, the electronic system determines the measured values of reference key velocity on the basis of the pieces of key data, accesses the velocity conversion table 31 for fingered keys so as to determine the target values of hammer velocity or target loudness, and supplies the music data codes to an electronic tone generator. The electronic tone generator produces an audio signal on the basis of the music data codes, and the audio signal is converted to electronic tones through a headphone.
In case where the present invention is applied to the mute piano, the central processing unit may also periodically execute the count-down subroutine, and transfer the MIDI music data code, in which the piece of hammer data Velo is stored, to an electronic tone generator when the associated piece of timing data reaches zero.
The computer program may be downloaded from an external program source through a communication network or read out from a portable information storage medium such as, for example, a floppy disk or a compact disk.
The pulse width modulator 25 does not set any limit to the technical scope of the present invention. A voltage regulator may be used for adjusting the potential level of a driving signal to a target value.
The usage in the study does not set any limit to the technical scope of the present invention. The velocity conversion table 30 for solenoid-actuated keys may be accessed in any situation where the solenoid-operated key actuators 8 give rise to the key motion. For example, while the central processing unit 20 is working for the playback, the central processing unit 20 may access the velocity conversion table 30 for solenoid-operated keys instead of the playback table.
Similarly, the velocity conversion table 31 for fingered keys may be accessed for a performance through another electronic musical instrument. The music data codes are transferred through a MIDI cable or a public communication network to the electronic musical instrument in a real time fashion, and the electronic musical instrument produces electronic tones on the basis of the music data codes. Thus, the usage in recording mode does not set any limit to the technical scope of the present invention.
The master automatic player piano does not set any limit to the technical scope of the present invention. Hammer sensors may be temporarily installed in the automatic player piano so as to carry out the experiments.
The hammer velocity does not set any limit to the technical scope of the present invention. Another master automatic player piano may equip pressure sensors instead of the hammer sensor, because the loudness of tones are also proportional to the force exerted on the strings 4. Otherwise, the sound pressure may be directly measured by a suitable sensor. Thus, the hammer motion may be expressed as the pressure exerted on the strings 4 or sound pressure.
The key motion may be also expressed as another sort of physical quantity. For this reason, the velocity conversion tables do not set any limit to the technical scope of the present invention.
The component parts of the automatic player piano are correlated with claim languages as follows. The black keys 1a and white keys 1b serve as “plural manipulators”, and the action units 2 and hammers 3 as a whole constitute “plural link works”. The strings 4 serve as a “tone generator”. The key sensors 7 are corresponding to “plural sensors”, and solenoid-operated key actuators 6 serve as “plural actuators”. The key position signals express “the motion of said plural manipulators”. The velocity conversion table 31 for fingered keys and velocity conversion table 30 for solenoid-actuated keys are corresponding to a “converter” and “another converter”, respectively.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-177314 | Jun 2004 | JP | national |
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| Number | Date | Country | |
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| 20060000339 A1 | Jan 2006 | US |
