JPH04191894A - Keyboard musical instrument - Google Patents

Abstract

PURPOSE:To improve timbres and sound volume by calculating and storing the vibration state of a tensed string and a virtual string of the same interval as this tensed string in accordance with the line spectrum indicating the vibration state of the tensed string, selecting the vibration state the virtual string of the same interval as the interval of a pressed key from a memory means, converting this state to a sound and outputting this sound at the time of performance. CONSTITUTION:The sound corresponding to the tensed string is produced if this string is struck. A memory means 100 calculates and stores the vibration state of the virtual string of the same interval as the interval of this tensed string in accordance with the ray spectra indicating this vibration state. A selecting means 300 selects the vibration state of the virtual string of the same interval as the interval of the struck tensed string out of the memory means 100 when the key detecting means 200 detects the pressed key at the time of performance. A sound production by the striking of the tensed string and the sound production by the sound producing means 400 are simultaneously executed in this way. The timbres and sound volume thereof are both improved.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a single-string keyboard instrument, and calculates the vibration state of a virtual string having the same pitch as the strung string based on the vibration state when the strung string is struck. This system improves the tone of a single-string keyboard instrument by storing it in memory and, when playing, producing the sound of a virtual string at the same pitch as the strung string, along with the sound of the string being struck, based on the above memory. be.

<Prior Art> Conventionally, as this type of keyboard instrument, a monochord piano (or two-string piano), in which only one (or two) strings are strung for six keys, has been known. That is, unlike a normal three-string piano, only one (or two) strings for each of the six keys are strung on the frame.

<Problems to be Solved by the Invention> However, such conventional monochord pianos have had problems in that the tone quality is inferior to that of ordinary three-string pianos, and the volume is also low.

In other words, the rich sound of a normal piano is due to
This is because there are three (rarely four) strings that act as sound sources, and each string has slightly different pitches, line spectra, attenuation, etc. On the other hand, a piano with one (or two) strings has inferior tone even if the tension per string is the same as that of a three-string piano.

SUMMARY OF THE INVENTION An object of the present invention is to provide a single-string keyboard instrument with excellent tone color and increased volume by reading partial tones before a string is struck from a storage means and producing the sounds.

<Means for Solving the Problems> As illustrated in FIG. 1, the present invention is a keyboard instrument in which one or two strings are stretched corresponding to each of a plurality of keys, Detecting the vibration state of the stretched string, based on at least a line spectrum indicating the detected vibration state,
A storage means 100 for calculating and storing the vibration state of a virtual string having the same pitch as the strung string, a key detecting means 200 for detecting a pressed key during performance, and a strung string corresponding to the pressed key. The storage means 1 stores the vibration state of the virtual string having the same pitch as the string.
This is a keyboard instrument comprising a selection means 300 for selecting from 00, and a sound generation means 400 for converting the selected vibration state into sound and outputting it.

<Function> In the keyboard instrument according to the present invention, by striking the strung strings, a sound corresponding to the strings is produced.

The storage means 100 calculates and stores the vibration state of a virtual string having the same pitch as the stretched string based on the line spectrum indicating the vibration state of the stretched string.

When the key detection means 200 detects a pressed key during performance, the selection means 300 selects from the storage means 100 the vibration state of a virtual string having the same pitch as the strung string that was struck.

Then, the sound generating means 400 converts the vibration state of the virtual string into sound and generates sound.

As a result, the sound produced by striking the strung strings and the sound generation means 400
and the pronunciation will be made at the same time, and the tone,
The volume is also improved, and it is possible to obtain a tone and volume equal to or greater than that of a three-string piano.

<Embodiments> Hereinafter, embodiments of the keyboard instrument according to the present invention will be described with reference to the drawings.

FIGS. 2 to 6 are diagrams for explaining one embodiment of the present invention.

FIG. 2 is a block diagram showing the general structure of a keyboard instrument according to an embodiment of the present invention.

In this figure, 21 is a frame in a vertical piano, and this frame 2] has one key per key 22.
A real string 23 is stretched with a tuning pin 24, a hitch pin, etc.

25 is a sound board arranged on the back side of this frame 21, and 26 is a piece fixed to the sound board 25. As this frame 21 has a small number of stretched strings 23 (usually 3 strings for 6 keys), the tension that is applied as a whole is significantly reduced, and a small and lightweight frame 21 is used. ing.

The other components and mechanisms are the same as those of a conventional three-string vertical piano.

For example, an action 27 is provided for each &122, and the hammer 28 of the action 27 is configured to strike and sound the single value 23.

The piezoelectric element 30 that detects the vibration state of these strings 23 is attached to the string holder at the top of the frame 21 (it may also be a bridge).
attached. This piezoelectric element 30 covers all the strings 23.
(For example, 88 strings) are arranged in a direction perpendicular to the strings 23, respectively.

Note that this piezoelectric element 30 may be any element that picks up the vibrations of the strings 23, and may be constructed from other mechanical-electrical transducers.

Also, the catcher 31 rotates together with the hammer 28.
A reflective optical sensor 32 is disposed opposite the end surface of the hammer 28, and this optical sensor 32 detects the string-striking speed of the hammer 28 (strictly speaking, the amount of displacement with respect to the catcher 31).

Further, a key sensor 34 as a key detecting means for detecting a pressed key 22 is disposed on a keyboard reed 33 disposed below the multi-cone 22. These key sensors 34 are configured as reflected light type optical sensors.

Furthermore, an actuator 35 that is electromagnetically driven to vibrate the sound board 25 is disposed at a predetermined position on the back surface of the sound board 25. Reference numeral 36 denotes an external speaker built into the main body of the piano, which generates sound by a drive circuit to be described later. These actuators 35, external speakers 36
constitutes a pronunciation means.

Further, a mode changeover switch 37 is provided on the lower surface of the arm, and this mode changeover switch 37 is equipped with an electronic control circuit 3 mainly composed of a microprocessor, which will be described later.
8 operation modes. For example, string 23
The recording mode detects and records the vibration state of the string 23, the data processing mode calculates the vibration state of the virtual string from the vibration state of the string 23, and the performance mode plays in response to key presses. Make the switch.

Here, in this vertical piano, the vibration state of the string 23 is detected, the vibration state of the virtual string is calculated based on the line spectrum indicating this vibration state, and the predetermined vibration state of the string is calculated from the sound produced by the hammer 28 when the string is struck. It has a configuration that allows sound to be generated via the actuator 35 or the external speaker 36 within a time period (5 msec).

That is, the vibration of the string 23 struck by the hammer 28 that rotates in response to the key press is detected by the piezoelectric element 30, and this string vibration signal is transmitted to the high-cut filter 41, for example.
High frequency components of 8,000 [Hz] or higher are gradually cut off as noise.

The string vibration signal after noise removal is input manually to the input/output section 42 of the electronic control circuit 38. In this input/output section 42, the string vibration signal is converted into a digital signal by an A/D converter, and then subjected to Fourier transform using, for example, FFT (fast Fourier transform) processing and processed as a line spectrum signal.

For the line spectrum signal, the electronic control circuit 38
Performs the following calculation processing.

For example, inharmonicity correction calculations, virtual string vibration data calculations, damping correction calculations are performed, and the first and second
First and second virtual string vibration signals are calculated by inverse Fourier transform of each virtual string data.

The electronic control circuit 38 calculates and stores the first and second virtual string vibration signals every 5 [m5ec] after the string is struck, and converts the first and second virtual string vibration signals into analog signals using a D/A converter in the input/output section 42 during the performance mode. and output to the drive circuit 43 or 44 as first and second virtual string vibration signals, respectively.

The drive circuit 43 is fixed to the soundboard 25 and drives the actuator 35 for driving the soundboard, which vibrates the soundboard 25 to produce sound.

Further, the drive circuit 44 drives the external speaker 36.

Therefore, the electronic control circuit 38 that performs the above-mentioned arithmetic processing, etc., which operates the drive circuit 43 or 44 according to the setting of the mode selector switch 37 and causes the sound board 25 or the external speaker 36 to produce sound, has a well-known configuration. CPU45
, R0M46, RAM47, and input/output section 42. The electronic control circuit 380 input/output unit 42 includes an A/D converter, a D/A converter, a multiplexer, etc.
Furthermore, the backup RAM 48 is an electronic control circuit 380C.
It has a configuration in which it is connected to P045 etc. by a bus. Further, 49 is a clock circuit H (clock generator), which supplies a clock signal to the CPU 45. 50
is a power source (battery) for the backup RAM 48.

The backup RAM 48 is a storage circuit for storing the line spectrum signal indicating the string vibration state, and is configured to have a predetermined storage capacity.

Furthermore, 51 is a hammer speed detection circuit that calculates and detects the hammer speed based on the detection signal of the optical sensor 32, 52 is an audio output terminal, and 53 is a MIDI output terminal.

Accordingly, the input/output section 42 of the electronic control circuit 38 receives l! which is pressed from the key sensor 33. The key number 22, the hammer speed from the hammer speed detection circuit 51, and the signal indicating the vibration state of the string 23 from the high-cut filter 41 are input, respectively.

Then, on the third day of the electronic control circuit, from this human output section 42,
A drive signal is selectively output to the drive circuits 43 and 44, an audio output signal is output to the audio output terminal 52, and a MIDI signal is selectively output to the MIDI output terminal 53.

Therefore, in this vertical piano, the strings are struck by the hammer 28 via the action 27 in response to the player's key presses to obtain the desired sound (strike sound), as in a normal piano.

In this vertical piano, all the strings 23 are
A line spectrum signal indicating the vibration state based on the second virtual value is calculated and stored.

Then, at the time of performance, the sound generation means (35 or 36) generates sound based on the line spectrum of this virtual value at the same time as the strings are struck. As a result, it is possible to obtain sound with a tone color and volume equal to or greater than that of a conventional three-string piano.

In other words, the calculation of the line spectrum indicating the vibration state based on the above-mentioned virtual values is performed in order to obtain a tone color and volume as rich as or better than that of a conventional three-string piano.

For example, this is done to slightly shift the pitch.

This produces a sound of this one-string vertical piano of 88Xn depending on the hammer speed (for example, 5
all steps) are stored as digital signals. Then, convert the digital data into 0.3 cents or 0.3 cents. It is memorized with a slight shift of 2 cents. When a key is pressed, the key number, hammer speed (
When the shifted sounds stored in the memory are read out and sent to the speaker based on the sound (or key pressing speed), one live sound (string hitting sound) and two generated sounds that are slightly shifted from this sound are generated almost simultaneously.

In this case, since the rise of an acoustic piano's sound is about 20 m5ec for low notes and about several m5ec for high notes, the timing of the sound generation is adjusted according to these ranges.

It is also used to adjust the line spectrum.

Noise-like harmonics are removed using a low-pass filter.

If the bass strings are too short, excessive anharmonicity will occur. In other words, the pitch of the harmonic wave shifts excessively, resulting in a loss of pitch and other deterioration in sound quality. Therefore, by calculating the frequency of each harmonic component of the memorized sound to be shifted until it becomes appropriate and storing it in the memory again, a sound with a good pitch feeling can be obtained. At this time, it is better to perform at a low tone, such as by shortening the string striking distance so that the live player is small. For example, the performer may play by depressing the soft pedal. Alternatively, the playing technique of releasing the key immediately after pressing the key stops the living person immediately. Furthermore, it is also effective to generate partials other than integer overtones by canceling them through electrical processing (for example, using a bandpass filter such as a tuner).

The operation will be specifically explained below with reference to flowcharts and graphs.

First, recording of a line spectrum signal indicating the vibration state caused by each string 230 being struck will be described. After this recording, a virtual vibration signal is calculated and stored by data processing.

In this case, the electronic control circuit 38 is set to the recording mode by the mode changeover switch 37.

In the recording mode, when a key is pressed, the hammer 28 rotates and strikes the string 23 stretched on the frame 21, and the key sensor 33 detects the key number of the pressed key 22. Further, the corresponding piezoelectric element 30 detects the vibration state of the string 23 as an electric signal. Further, the hammer speed is detected by the optical sensor 32 and the hammer speed detection circuit 51.

These detection signals are then input to the human output section 42 of the electronic control circuit 38, subjected to signal processing, and stored as a line spectrum indicating the vibration state of the string.

FIG. 3 is a flowchart showing the procedure of this recording process. The electronic control circuit 38 stores actual string vibration data for all strings 23 according to this program.

First, while initializing the CPU 45 and others,
Enter O into variable N (step 531).

The variable N is a variable indicating the number of data.

Next, a key operation signal is manually input from the key sensor 34 (S
32). As a result, the key number of the pressed key 22 is detected.

Further, the hammer speed is manually input from the hammer speed loading/unloading PI31 (S33).

Then, the string vibration signal detected by the piezoelectric element 30 is A/D converted at predetermined time intervals and input as sampling data (S34). In this case, the high-cut filter 41 removes harmonic components from the string vibration signal as noise. Furthermore, the sampling interval of the string vibration signal is set to 1/2 or less of the shortest cycle component to prevent aliasing. Further, the A/D conversion starts at the same time as the start of sound generation, and ends when it is assumed that the sound has decayed by tJi5 and is silenced.

Next, this sampling data is subjected to Fourier transform using a fast Fourier transform program to calculate a line spectrum (S35).

Further, the actual string vibration data including the key number, hammer speed, and line spectrum is temporarily stored in the RAM 47 (536).

Then, increment the number of data by 1 (537)
, it is confirmed whether the recording mode has ended based on the input from the mode changeover switch 37 (S38). If the process has not been completed, the process returns to step S32.

This recording process is used to create the tone of a monochord piano.
At least one will be rushed at first. Thereafter, it may be performed again at any time desired by the performer.

In addition, the performer usually changes the pressing strength of the keys in the order of keys numbered 1 to 88, for example, pl)j.
Then, press the key in five steps such as mf, f, ff, etc. and record it.

Through this recording process, the line spectrum of the vibration of the string actually struck against the pressed key is temporarily stored in the RAM 47 as actual string vibration data, along with its key number and hammer speed. . The total number N of data in this case is 88×n. n is the number of key pressing strength levels, for example 5.

After this line spectrum signal is recorded, data processing is performed to calculate a line spectrum signal indicating a desired vibration state of the virtual string based on this line spectrum signal and the like.

Data processing is executed by the electronic control circuit 38 by switching the mode changeover switch 37 to the data processing mode.

FIG. 4 is a flowchart showing a program for this data processing.

To explain with reference to this figure, first, a counter CNT is initialized by assigning 1 to it (S41).

Next, the actual string vibration data specified by the data number is
A, read from M47 (S42).

First, anharmonicity correction processing is performed on this realized vibration data (S43).

FIG. 5(A) is a graph of a line spectrum for explaining anharmonicity correction of real string vibration data.

This correction is to correct the frequency of the high-order harmonic component shown in the line spectrum, for example, the frequency of the n-th harmonic to a frequency that provides appropriate anharmonicity. In the graph, ・ indicates actual vibration data, ○ indicates vibration data after anharmonic correction,
are shown respectively.

Assuming the fundamental tone fe at the time of pronunciation (te), the nth harmonic n,
f e becomes the frequency represented by nfil' after correction.

In this case the strength is the same. Also, 5 msec
The subsequent correction at tl and the correction of higher harmonics at t2 5m5ec later are corrections that lower the frequency.

For example, as a method for quantitatively determining appropriate inharmonicity, an arithmetic expression (formula ■) or a map that defines the mutual relationship between the key number and the parameter b value is
It is stored in the ROM 46 in advance.

Then, the actual vibration data read this time (S42)
In accordance with the key number, a parameter b value indicating appropriate anharmonicity is determined according to the arithmetic expression or map stored in the ROM 46.

Based on the parameter b value obtained in this way, the nth
Anharmonicity-corrected data is obtained by performing correction to reduce the frequency of the actual string vibration data, especially the higher-order harmonics, so that there is an appropriate difference in pitch (pitch) from the next harmonic. This data becomes the data at that time te.

1200 ・1 o g2 (fr, /n 4 fs) =
b # n2・・・・・・・・・・・・■ Here, fo[Hz is the harmonic frequency, nfs[H2]
is the frequency of the nth harmonic. Note that n is an integer, and the unit on the right side is cents.

As described above, the frequency of the n-th overtone is corrected to decrease to f.

Next, in step S44, virtual string vibration data is calculated based on the actual string vibration data after the anharmonicity correction process.

FIG. 5(B) is a graph for explaining calculation of the first virtual string vibration data and the second virtual string vibration data. In the figure,
The mouth indicates first virtual string vibration data (right string), △ indicates second virtual string vibration data (left string), and ○ indicate actual string vibration data after anharmonicity correction processing.

This correction is based on the fundamental tone f8 and overtone 2 of the data after anharmonicity correction.
This is a correction that increases or decreases the frequency of f@xnf6'~, and 0.
Fundamental tone f1 of the first virtual string vibration data 2 cents lower, overtone 2
f+~nf+'~ and 0. The fundamental tone f2 and overtones 2f2 to nf2' of the second virtual string vibration data that are 3 cents higher are calculated.

In order to create the sound of a piano that has three strings for one key, we apply anharmonic correction to the actual string vibration data obtained by hitting the first string (center string). The first virtual string vibration data (right string) and the second virtual string vibration data (right string) are calculated based on the harmonicity correction processed data.

Here, the pitch of the right string is 0.2 cents lower than the pitch of the middle string, while the pitch of the right string is 0.2 cents lower than that of the middle string.
．． An example of setting the price 3 cents higher is shown below. Note that the pitch difference between the left and right strings with respect to the center string does not have to be uniform.

It is assumed that a pitch difference parameter that determines the pitch is stored in advance in the ROM 46 in correspondence with each key number.

Then, the anharmonicity corrected data (fs, 2fθ.

...nfe' ...) to 0. The first virtual string vibration data (f+, '2f+, ...) is lowered by 2 cents.
・nf+'...) is calculated. The frequency of the fundamental tone f1 is determined by the equation (-0,2=12001og2(f+/f
Calculated from s)). The frequencies of overtones 2 f + . . . are calculated in the same manner.

Roughly, anharmonicity corrected data (fe, 2ft!.

...nfs' ...) to 0. The second virtual string vibration data (fe, 2f2....) is increased by 3 cents.
... nf2' ... Calculate n. The frequency of the fundamental tone f2 is determined by the equation (0,3=12001og2(f2/
fe) Calculated from >. The frequencies of overtones 2 f 2 . . . are calculated in the same manner.

Next, in step 545, a damping correction process is performed based on the virtual string vibration data after the virtual string vibration data calculation process.

FIG. 5(C) is a graph of a line spectrum for explaining intensity attenuation correction over time.

In the figure, the opening indicates first virtual string vibration data, ■ indicates first virtual string data after damping correction, Δ indicates second virtual string vibration data, and M indicates second virtual string data after damping correction.

This correction is performed in such a way that the elapsed time (
t+, t2), the intensity is increased or decreased, and the first
, the second virtual string data, and m are calculated.

First, the damping characteristics of the actual string vibration data included in the first virtual string vibration data RO and the second virtual string vibration data Δ are corrected.

Generally, due to energy loss in the process of energy being transmitted from the strings to the soundboard via the bridge, the intensity I(t) at time t is
less than the preferred target value. On the contrary, only specific overtone components,
Attenuation is slow and the balance with other overtones may be lost.

In this case, the intensity correction factor Δ for each elapsed time for the fundamental tone and each overtone
I (t) is stored in the ROM 46 in advance.

After the string is struck, the intensity correction value DI(t
) is calculated as shown in the following equation based on the intensity 1 (o) at the time of pronunciation.

1) I (t) =I (o)

1 (t)=I (t)+DI (t) I on the left side (
t) is the intensity after attenuation correction, I(t) on the right side is the intensity before correction, DI(t) is the intensity correction value at time t,
are shown respectively.

Then, this correction calculation is performed for each fundamental tone, each overtone, and each time.

FIGS. 5(D) and 5(E) respectively show the first virtual string data and the second virtual string data calculated in the above manner as line spectra.

Next, in step 546, the line spectrum of the first virtual string data (FIG. 5(D)) and the line spectrum of the second virtual string data (FIG. 5(E)) obtained by the above-mentioned processes are calculated.
) is subjected to inverse Fourier transform to calculate first and second virtual string vibration signals.

Then, these first and second virtual string vibration signals, key numbers, and hammer speeds are stored in the backup RAM 48 as first and second virtual string vibration data (S47).

Next, by checking whether the counter value matches the data number N (S48), steps 542 to S47 are performed while incrementing the counter CNT by 1 (S49) until the processing for all data is completed. Execute repeatedly.

As described above, when the calculation and storage of the virtual string data is completed, the CPU 45 will
Run the program shown in the figure.

At this time, the mode changeover switch 37 has been switched to the performance mode.

During a performance, a string strike sound is produced by the player pressing a key, and at the same time, the processing shown in this flowchart is performed to produce a sound on the soundboard 25 via the drive circuit 43 or 44.
Alternatively, sound is generated from the external speaker 36. The sounds produced by these means 25 and 36 are based on the virtual string data.

First, a detection signal from the key sensor 34 is input for the pressed key, and the hammer speed is calculated and input manually (S61).

Next, the first and second virtual string vibration signals corresponding to the actually struck string 23 and its key depression intensity (calculated from the hammer speed) are read from the backup RAM 4B (S62).
.

Then, through subroutine processing, a three-dimensional map (RO
According to M48 Storage>, an appropriate sounding timing is calculated according to the detected key number and hammer speed (S63).
.

At the sound generation timing calculated in this way, the first and second virtual string vibration signals are output for any one (selected) of the actuator 35 for driving the soundboard 25, the external speaker 36, and the audio output terminal 52. (S64). In addition, the key number, hammer speed (velocity), and sound timing (timing) are output to the Mlll output terminal 53 (
S65).

Then, check the setting of the mode changeover switch 37 (366), and repeat steps S61 to S65 until the performance ends.

Furthermore, by disabling the electrical system, it can be easily used as a single-string piano, and can be used as a low-volume practice piano.

Furthermore, MIDI signals can be outputted via the MrDa input terminal 53, allowing unsampled performances with other electronic musical instruments, MIDI devices (music computers, etc.), etc.

Furthermore, if the delay processing of the MIDI signal [500m5eC] is taken into consideration, it becomes possible to perform in concert with a player piano.

<Effects of the Invention> As explained above, according to the keyboard instrument according to the present invention, the tone color is significantly improved compared to the conventional monochord piano. The volume has also been improved. Furthermore, the volume can be adjusted by adjusting the increase rate and the like. Since the volume increases, it becomes possible to perform at a lower tone.

The timbre and volume of these can be increased to a level equal to or higher than that of a three-string piano.

Furthermore, since the tension acting on the frame of this single-string piano is smaller than that of a three-string piano, the frame can be made lighter and smaller.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram illustrating a schematic configuration of a keyboard instrument according to the present invention, FIG. 2 is a block diagram showing the overall configuration of a keyboard instrument according to an embodiment of the present invention, and FIG. 3 is an example of an embodiment. FIG. 4 is a flowchart showing a data processing procedure according to an embodiment, and FIGS. 5(A) to (E) are vibrations of a virtual string according to an embodiment. A graph showing a line spectrum for explaining the state calculation process. FIG. 6 is a flowchart showing the performance process according to one embodiment. 100... Storage means, 200... Key detection means, 300...
...Selection means, 400...Pronunciation means. Patent Applicant Yamaha Corporation Representative Patent Attorney Kiyoshi Kuwai - Figure 1 Keyboard instrument of the present invention 10-, Kuro 11! Figure S (A+ Figure S (D) Figure S (El

Claims (1)

[Scope of Claims] A keyboard instrument in which one or two strings are strung corresponding to each of a plurality of keys, which detects the vibration state of the strung strings, and detects at least the detected vibration. A storage means for calculating and storing the vibration state of a virtual string having the same pitch as the stretched string based on a line spectrum indicating the state; a key detection means for detecting a pressed key during performance; a selection means for selecting from the storage means a vibration state of a virtual string having the same pitch as a strung string corresponding to a key; and a sound generation means for converting the selected vibration state into sound and outputting it. A keyboard instrument characterized by