JP7156345B2 - Electronic musical instrument, musical tone generating method and program - Google Patents

Description

The present invention relates to an electronic musical instrument, a musical tone generation method, and a program.

There has been proposed a technique for a resonance generator that can more faithfully simulate the resonance of an acoustic piano. (For example, Patent Document 1)

JP 2015-143764 A

The sound source method of the physical model of the piano generates only a basic string model, and the output is monaural. As a general method for stereophonizing the output, piano modeling that has two sets of independent string models for the excitation signal and percussion signal for the left channel and the right channel for one key of the piano. method is considered.

In this way, if one key has two sets of signal processing systems for stereo conversion, the amount of signal processing required is simply twice that of monaural. For example, if each key has 1 to 3 strings and the total number of keys is 88, the total number of strings is about 230. Therefore, when two sets are required for stereo, about 460 string models are required, which increases the amount of signal processing and increases the load on the circuit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to provide an electronic musical instrument and a musical tone generation method capable of generating musical tones with a good stereo feeling while suppressing the amount of signal processing. and to provide programs.

According to one aspect of the present invention, at least the first closed loop among the first closed loop, the second closed loop and the third closed loop provided corresponding to the pitch in response to the input of the excitation signal corresponding to the specified pitch generating a string sound signal output from one of the left and right channels based on an accumulated signal obtained by accumulating the outputs from the closed loop and the second closed loop, and accumulating the outputs from the second closed loop and the third closed loop; A string sound signal to be output from either the left or right channel is generated based on the accumulated signal.
According to another aspect of the present invention, a first closed loop, a second closed loop, a third closed loop, and a fourth closed loop are provided corresponding to the specified pitch in response to the input of an excitation signal corresponding to the specified pitch. generating a string sound signal output from either one of the left and right channels based on an accumulated signal obtained by accumulating outputs from the first closed loop, the second closed loop and the third closed loop in the A string tone signal output from either the left or right channel is generated based on an accumulated signal obtained by accumulating outputs from the second closed loop, the third closed loop and the fourth closed loop.

According to the present invention, it is possible to generate musical tones with a good stereo feeling while suppressing the amount of signal processing.

1 is a block diagram showing the configuration of a basic hardware circuit of an electronic keyboard instrument according to an embodiment of the present invention; FIG. FIG. 2 is a block diagram showing, as a hardware circuit configuration, functions executed by a sound source DSP according to the embodiment; FIG. 4 is a diagram exemplifying the frequency spectrum of the fundamental tone and overtones of the string tone according to the embodiment; The figure which illustrates the frequency spectrum of the impact sound which concerns on the same embodiment. FIG. 4 is a diagram illustrating frequency spectra of musical tones according to the embodiment; FIG. 4 is a diagram for explaining the concept of generating waveform data of a string sound by a closed loop circuit from waveform data of an excitation impulse of the string sound according to the embodiment; FIG. 5 is a diagram showing the relationship between the frequencies of string tones assigned to three string models and the beat caused by the difference in those frequencies according to the same embodiment. FIG. 3 is a block diagram showing, as a hardware circuit configuration, functions executed by a sound source DSP in place of FIG. 2 according to the embodiment;

An embodiment in which the present invention is applied to an electronic keyboard instrument will be described below with reference to the drawings.
[Constitution]
FIG. 1 is a block diagram showing the configuration of a basic hardware circuit of an electronic keyboard instrument 10 according to this embodiment. An operation signal including a note number (pitch information) and a velocity value (key depression speed) as volume information is input to the CPU 12A of the LSI 12 according to the operation on the keyboard 11, which is a performance operator.

The LSI 12 connects a CPU 12A, a ROM 12B, a RAM 12C, a sound source 12D, and a D/A converter (DAC) 12E via a bus B.

The CPU 12A controls the operation of the electronic keyboard instrument 10 as a whole. The ROM 12B stores an operation program executed by the CPU 12A, excitation signal waveform data for performance, percussion sound waveform data, and the like. The RAM 12C is a work memory used when the CPU 12A reads out an operation program stored in the ROM 12B, develops and stores the program, and executes the program. The CPU 12A provides parameters such as note numbers and velocity values to the tone generator 12D during performance operations.

The tone generator 12D has a DSP (digital signal processor) 12D1, a program memory 12D2 and a work memory 12D3. The DSP 12D1 reads out the operating program and fixed data stored in the program memory 12D2, develops and stores them in the work memory 12D3, and executes the operating program, so that the ROM 12B Based on the necessary waveform data for string tone excitation signals and percussive sound waveform data, stereo musical tone signals for the left and right channels are generated by signal processing, and the generated musical tone signals are output to the D/A converter 12E. .

The D/A converter 12E converts the stereo musical tone signals into analog signals and outputs them to amplifiers (amp.) 13L and 13R. Speakers 14L and 14R amplifies and emits musical sounds as stereo sounds by the analog left channel and right channel musical sound signals amplified by the amplifiers 13L and 13R.

FIG. 1 illustrates the configuration of the hardware circuit when applied to the electronic keyboard instrument 10. The functions executed in this embodiment are executed by an application program installed in an information processing device such as a personal computer. If so, the CPU of the device executes the operation in the tone generator 12D.

FIG. 2 is a block diagram mainly showing the functions executed by the DSP 12D1 of the tone generator 12D as a hardware circuit configuration. In the figure, the area indicated by II in the figure corresponds to one key included in the keyboard section 11, except for the note event processing section 31, waveform memory 34, and adders 42L and 42R, which will be described later. In this electronic keyboard instrument 10, assuming that the keyboard section 11 has 88 keys, similar circuits are provided for 88 keys. The electronic keyboard instrument 10 has a three-string model signal circulation circuit per key to generate a stereo musical tone signal.

A note-on/off signal corresponding to the operation of the keys on the keyboard section 11 is input to the note event processing section 31 from the CPU 12A.

The note event processing section 31 sends each information of the note number and velocity value at the start of sounding (note-on) to the waveform reading section 32 and the windowing processing section 33 according to the operated key, and also outputs each string model. , a note-on signal and a multiplier corresponding to the velocity value are sent to the gate amplifiers 35A to 35E of the striking sound.

Furthermore, the note event processing section 31 sends a signal indicating the amount of feedback attenuation to the attenuation amplifiers 39A-39C.

The waveform reading section 32 generates a read address corresponding to the note number and velocity value information, and reads out the waveform data as the excitation signal of the string sound and the waveform data of the striking sound from the waveform memory 34 (ROM 12B). Specifically, the excitation impulse of the left channel string tone (Excitation IL), the excitation impulse of the centrally localized string tone (Excitation IC), the excitation impulse of the right channel string tone (Excitation IR), and the percussion sound of the left channel (Excitation L). , and the right channel impact sound (strike R) are read out from the waveform memory 34 and output to the windowing processing section 33 .

The windowing processing unit 33 performs windowing (window function ) processing, and the waveform data after the windowing processing is sent to the gate amplifiers 35A to 35E.

First, one of the three-string model signal circulation (closed loop) circuits, which is the rear stage of the uppermost gate amplifier 35A, will be described. On the post-stage side of the gate amplifier 35A, temporally continuous left channel string sound waveform data is generated.

The gate amplifier 35A amplifies the windowed waveform data with a multiplier corresponding to the velocity value, and outputs the processed waveform data to the adder 36A. Waveform data after attenuation processing output from an attenuation amplifier 39A, which will be described later, is fed back to the adder 36A, and the added output is output to the delay circuit 37A as the string model output.

The delay circuit 37A is set with a string length delay value corresponding to one wavelength of the sound output when the string vibrates in the acoustic piano, and delays the waveform data by the string length delay, It is output to the low-pass filter (LPF) 39A in the subsequent stage. That is, the delay circuit 37A delays by a time (a time corresponding to one wavelength) determined according to the input note number information (pitch information).

The low-pass filter 38A passes the waveform data on the lower side than the cutoff frequency for wide-range attenuation set for the frequency of the chord length, and outputs the waveform data to the adder 40A and the attenuation amplifier 39A. The output of this low-pass filter 38A becomes the waveform data of the string sound of the left channel (for one string) that is continuous in time.

The attenuation amplifier 39A performs attenuation processing according to the feedback attenuation amount signal supplied from the note event processing section 31, and feeds back the waveform data after attenuation to the adder 36A.

On the post-stage side of the gate amplifier 35B in the second stage, the waveform data of the centrally localized string tones shared by the left channel and the right channel are generated from the waveform data of the excitation impulse (excitation IC) of the centrally localized string tones.

The circuit configuration and operation of the post-stage of the gate amplifier 35B, the adder 36B, the delay circuit 37B, the low-pass filter 38B, and the attenuation amplifier 39B are the same as those of the upper stage. , are output to the adder 40A in the upper stage and the adder 40C in the third stage.

The adder 40A adds the waveform data of the left channel string sound output from the low-pass filter 38A and the waveform data of the centrally localized string sound output from the low-pass filter 38B. Waveform data is output to the adder 41A.

On the post-stage side of the third-stage gate amplifier 35C, a right-channel string tone signal is generated from the waveform data of the excitation impulse (excitation IC) of the right-channel string tone.

The circuit configuration and operation of the post-stage of the gate amplifier 35C, the adder 36C, the delay circuit 37C, the low-pass filter 38C, and the attenuation amplifier 39C are the same as those of the upper stage. , is output to the adder 40C. The output of this low-pass filter 38C becomes the waveform data of the string sound of the right channel (for one string) that is continuous in time.

The adder 40C adds the waveform data of the right channel string sound output from the low-pass filter 38C and the waveform data of the centrally localized string sound output from the low-pass filter 38B. Waveform data is output to the adder 41C.

In the fourth-stage gate amplifier 35D, the waveform data (strike L) of the left-channel hit sound read out through the windowing processing section 33 is amplified by a multiplier corresponding to the velocity value, and the post-processing is performed. Waveform data is output to the adder 41A.

The adder 41A adds the waveform data of the left channel string sound output from the adder 40A and the waveform data of the left channel percussion sound output from the gate amplifier 35D. It is output to the adder 42L as waveform data of the superimposed tone.

In the gate amplifier 35E of the fifth stage, the waveform data (strike R) of the right-channel hit sound read out through the windowing processing section 33 is amplified by a multiplier corresponding to the velocity value. Waveform data is output to the adder 41C.

The adder 41C adds the waveform data of the right channel string sound output from the adder 40C and the waveform data of the right channel percussion sound output from the gate amplifier 35E. It is output to the adder 42R as waveform data of the superimposed tone.

The adder 42L adds the waveform data of the left channel tone of each key being pressed on the keyboard section 11, and outputs the sum to the D/A conversion section 12E in the next stage for tone generation.

Similarly, the adder 42R adds the waveform data of the right channel tone of each key being pressed on the keyboard section 11, and outputs the sum to the next-stage D/A conversion section 12E for tone generation. .

[motion]
Next, the operation of the embodiment will be described.
First, the concept of generating musical tones by superimposing and adding string sounds and percussive sounds will be described with reference to FIGS.
FIG. 3 is a diagram illustrating the frequency spectrum of string tones. As shown, it has a frequency spectrum in which a peak-shaped fundamental f0 and its overtones f1, f2, . . .

Also, by performing processing to shift the frequency components of the fundamental f0 and its overtones f1, f2, .

A string tone that can be generated by such a physical model does not include anything other than the fundamental tone component and overtones, as shown in FIG. On the other hand, the musical sound generated by the original musical instrument contains musical sound components, which may be called percussion sounds, and these musical sound components, which may also be called percussion sounds, characterize the musical sounds of the musical instrument. Therefore, in electronic musical instruments, it is desirable to generate this percussive sound and synthesize it with the string sound.

Note that, in this embodiment, for example, in an acoustic piano, the impact sound when a hammer collides with a string inside the piano when a key is pressed, the operating sound of the hammer, the sound of the piano player's finger hitting the key, and the sound of the key hitting the stopper. It includes sound components such as the sound when hitting and stopping, and does not include pure string sound components (fundamental tone components and overtone components of each key). Note that the hitting sound is not necessarily limited to the sound of the physical hitting action itself that occurs when the key is pressed.

In generating the percussion sound, first, the waveform data of the recorded musical sound is windowed by a window function such as a Hanning window, and then converted into frequency dimension data by FFT (Fast Fourier Transform).

For the converted data, the frequencies of the fundamental and overtones are determined based on the data that can be observed from the recorded waveform, such as the pitch information of the recorded waveform data, the overtone to be removed, and the deviation of the overtone frequency from the fundamental tone, and then The frequency component of the string sound is removed by performing arithmetic processing such that the amplitude of the resultant data at the frequency becomes zero.

For example, if the fundamental frequency is 100 [Hz], the frequencies at which the frequency components of string tones are removed by multiplication with a multiplier of 0 are 100 [Hz], 200 [Hz], 400 [Hz], 800 [Hz], . becomes.

Here, it is assumed that the harmonic overtone is an exact integer multiple, but since the frequency of the actual instrument is slightly different, it is more appropriate to use the overtone frequency observed from the waveform data obtained by recording. .

After that, the data from which the frequency component of the string sound has been removed is transformed into time-dimensional data by IFFT (Inverse Fast Fourier Transform), thereby generating the waveform data of the percussive sound.

FIG. 4 is a diagram exemplifying the frequency spectrum of the musical sound of the percussion sound. Waveform data of an impact sound having such a frequency spectrum is stored in the waveform memory 34 (ROM 12B).

By adding and synthesizing the waveform data of the percussion sound shown in FIG. 4 and the waveform data of the string sound generated from the physical model shown in FIG. 3, a musical sound having a frequency spectrum as shown in FIG. 5 is generated.

FIG. 5 is a diagram exemplifying the frequency spectrum of a musical tone generated when a note of pitch f0 on an acoustic piano is pressed. As shown in the figure, synthesizing a string sound in which a peak-like fundamental f0 and its overtones f1, f2, . . . can reproduce the musical tones of an acoustic piano.

Next, referring to FIG. 6, each closed loop circuit (36A to 39A, 36B to 39B, 36C to 39C) that constitutes the string model uses the waveform data of the excitation impulse of the string sound read from the waveform memory 34 (ROM 12B). A concept of generating waveform data of string tones that are continuously continuous will be described.
FIG. 6 is a diagram illustrating a method of generating an excitation signal from additive synthesis of dynamic waveforms at a pitch corresponding to a certain note number. The data at the beginning of the waveform data corresponding to the intensity are added at values indicated by the addition ratios shown in the figure, along the same time series as the storage address advances, so that the intensity varies.

Specifically, FIG. 6A shows about six cycles of waveform data of forte (f), which is the first waveform data with high intensity (strong sound intensity). For the data, as shown in FIG. 6B, an addition ratio signal is given to make the first two cycles effective. Therefore, the multiplier (amplifier) 21 multiplies the waveform data by using this addition ratio signal, which varies between "1.0" and "0.0", as a multiplier (amplification factor), and the resulting waveform is Data is output to adder 24 .

Similarly, FIG. 6(C) shows about six cycles of mezzo-forte (mf) waveform data, which is the second waveform data with moderate intensity (sound intensity is slightly strong). As shown in FIG. 6(D), an addition ratio signal is given to the data for validating about two central cycles. Therefore, the multiplier 22 multiplies the waveform data by using this addition ratio signal as a multiplier, and outputs the waveform data as the product to the adder 24 .

Similarly, FIG. 6E shows about six cycles of the waveform data of piano (p), which is the third waveform data with low intensity (weak sound intensity). As shown in FIG. 6(F), an addition ratio signal is provided to make the last two cycles effective. Therefore, the multiplier 23 multiplies the waveform data by using this addition ratio signal as a multiplier, and outputs the waveform data as the product to the adder 24 .

Therefore, the output of the adder 24 that adds these waveform data changes continuously from "strong"→"medium"→"weak" every two cycles, as shown in FIG. 6(G).

By storing such waveform data (excitation signal waveform data) in the waveform memory 34 (ROM 12B) and designating the start address according to the performance intensity, the necessary waveform data (partial data) can be obtained for string tone excitation. Read out as an impulse signal. As shown in FIG. 6(H), the read waveform data is subjected to windowing processing by the windowing processing unit 33 and supplied to each signal circulation (closed loop) circuit in the subsequent stage, thereby producing temporally continuous string sounds. waveform data is generated.

Since two to three wavelengths are used as waveform data, the number of sampling data constituting the waveform data differs depending on the pitch. For example, in the case of 88 keys of an acoustic piano, the number of sampling data is about 2000 to 20 (at a sampling frequency of 44.1 [kHz]) from low to high.

It should be noted that the method of adding waveform data described above is not limited to a combination of waveform data with different performance intensities of the same musical instrument. For example, in the case of an electric piano, when a key is pressed lightly, it has waveform characteristics close to a sine wave, while when the key is pressed hard, the waveform becomes a saturated rectangular wave. These waveforms with distinctly different shapes, and waveforms extracted from guitars, for example, are modeled by continuously adding musical tones of various different instruments and continuously varying them according to playing intensity and other performance controls. It can generate musical tones.

Next, the relationship between the frequency of the stereo string sound generated by the signal circulation (closed loop) circuit of the three-string model in FIG. 2 and the beat will be described.
FIG. 7 shows the frequencies of the string sounds assigned to the three string models and the difference between the frequencies when the note number pressed on the keyboard unit 11 is, for example, A4 "La" (440 [Hz]). is a diagram showing the relationship of beats caused by If the closed loop circuit of the three string tones shown in FIG. Allocate the original frequency of 440 [Hz], assign 440.3 [Hz] to the left channel string model of number "1", and 440.36 [Hz] to the right channel string model of number "3", The waveform data of the excitation impulse of the string tone of the corresponding frequency is read out and given to each string model. The ratio of these assigned frequencies is set based on the index. The delay time in the delay circuits 37A to 37C of each string model is set to one wavelength period of the assigned frequency.

As indicated by the associated string numbers, the difference in frequencies assigned to the two string numbers is reflected in the frequency and period of the beat produced when string tones of those two frequencies are superimposed. Three types of frequency beat components are generated from the three string models, but due to the relationship of addition, the beat components of strings 3 and 1 shown in the string number "3" column in FIG. is generated in the sound emission space only after the musical tone signals are amplified and emitted by the speakers 14L and 14R.

On the other hand, the beat component contained in the waveform data of the left channel string sound generated from the waveform data of the string sound for two strings output by the adder 41A is shown in the string number "1" column in FIG. The contents are shown. Similarly, the beat component contained in the waveform data of the right-channel string sound generated from the waveform data of the string sound for two strings output by the adder 41C is shown in the string number "2" column in FIG. The contents are shown.

In this way, by generating musical tones containing one beat component that is different for the left and right sides of the stereo musical tone signal and one kind of common beat component, it is possible to generate musical tones with a rich sense of stereo.

In addition, when three string models are required for one key in a typical electronic piano instrument, two sets of models for a total of six strings are required for stereo sound generation, as shown in FIG. In this configuration, the three-string model can generate stereo sound, so the amount of signal processing can be greatly reduced.

When a stereo musical tone signal is generated using string tone signals of three string models as described with reference to FIG. 2, string tone signals for left and right channels are each generated from two string models. As mentioned above, an actual acoustic piano contains one (lowest range), two (low range) or three (midrange and above) string tones per key. Therefore, especially in an environment where the left and right channels are not mixed in the space, for example, in an environment where musical sounds are played through headphones, etc., if only one of the left and right channels is heard, there is a possibility that the musical sound heard will be monotonous. occurs.

In order to deal with such a situation, it is conceivable to provide two systems of string models for generating centrally-localized string tones that are commonly used.

FIG. 8 is a block diagram showing, in place of FIG. 2, functions executed by the tone generator 12D' as a hardware circuit configuration. FIG. 8 basically conforms to the configuration of FIG. 2, and the same parts are denoted by the same reference numerals, and redundant explanations are omitted.

The waveform reading unit 32 retrieves the excitation impulse of the left channel string tone (excitation IL), the excitation impulse of the first centrally localized string tone (excitation IC1), and the excitation impulse of the second centrally localized string tone from the waveform memory 34 (ROM 12B). (excitation IC 2), the excitation impulse (excitation IR) of the right channel string sound, the left channel percussion sound (strike L), and the right channel percussion sound (strike R) are read out and sent to the windowing processing unit 33. Output.

The windowing processing unit 33 performs windowing (window function) processing particularly on the excitation impulses (excitation IL, excitation IC1, excitation IC2, excitation IR) of the string sound, and outputs the waveform data after the windowing processing to the gate amplifier 35A. Send to ~35F.

The gate amplifier 35F amplifies the waveform data of the excitation impulse of the second centrally localized string tone with a multiplier corresponding to the velocity value, and outputs the processed waveform data to the adder 36F. Waveform data after attenuation processing output from an attenuation amplifier 39F, which will be described later, is fed back to the adder 36F, and the added output is output to the delay circuit 37F as the output of the string model.

The delay circuit 37F is set with a string length delay of a value corresponding to one wavelength of the sound output when the string vibrates in the acoustic piano, and delays the waveform data by the string length delay, Output to the low-pass filter (LPF) 39F in the subsequent stage.

The low-pass filter 38A passes the waveform data on the lower side than the cutoff frequency for wide-range attenuation set for the frequency of the chord length, and outputs the waveform data to the adders 40D and 40E. The output of the low-pass filter 38F becomes waveform data of the second centrally-localized string sound that is temporally continuous.

The attenuation amplifier 39F performs attenuation processing according to the feedback attenuation amount signal supplied from the note event processing section 31, and feeds back the waveform data after attenuation to the adder 36F.

The adder 40D adds the waveform data of the left-channel string tone output from the low-pass filter 38A and the waveform data of the first centrally localized string tone output from the low-pass filter 38B to the output of the adder 40A. 2 are added, and the addition result is output to the adder 41A as the waveform data of the left channel (three strings) string tones.

Similarly, in the adder 40E, for the output of the adder 40C obtained by adding the waveform data of the right-channel string sound output from the low-pass filter 38C and the waveform data of the first centrally-located string sound output from the low-pass filter 38B, Further, the waveform data of the second centrally localized string tones are added, and the addition result is output to the adder 41C as the waveform data of the right channel (for three strings) string tones.

Assuming that the closed loop circuit of the four string tones shown in FIG. (440 [Hz]), the original frequency of 440 [Hz] is applied to the first centrally located string model of number "2", which is a common string model, and the second centrally located string model of number "3" A frequency of 440.66 [Hz] is assigned to each localization string model, and 440.3 [Hz] is assigned to the string model of the left channel of number "1", and 440.432 [Hz] is assigned to the string model of the right channel of number "4". Hz].

Beat components of four different frequencies are generated from the four string models. Due to the relationship of addition, the left channel tone has beat components of strings 4 and 1, and the right channel tone has beat components of strings 1 and 2. , is generated in the sound emission space only after the stereo musical tone signal is amplified and emitted by the speakers 14L and 14R.

If three string models are required for each key of a typical electronic piano, two sets of six string models are required for stereo sound generation. The four-string model can generate stereo sound, greatly reducing the amount of signal processing required.

In FIG. 8, by providing two string models for generating centrally localized string sounds that are commonly used, string sounds for left and right channels are generated from three string models, respectively. Therefore, even if you listen to only one of the left and right channels in an environment where the left and right channel musical sounds are not mixed in the space, for example, in an environment where the musical sound is played back with headphones, etc., the musical sound you hear will be monotonous. You can definitely eliminate the possibility of feeling ugly.

[Effects of Embodiment]
As described in detail above, according to this embodiment, it is possible to generate musical tones with a good stereo feeling while suppressing the amount of signal processing.

In addition, in this embodiment, in addition to the string sound containing the specified pitch and its harmonic components, the percussive sound peculiar to the instrument is superimposed and added to generate the stereo musical sound, so the amount of signal processing is suppressed. However, it is possible to favorably generate more natural musical tones.

As described above, the present embodiment has been described as applied to an electronic keyboard musical instrument, but the present invention is not limited to musical instruments or specific models.

In addition, the present invention is not limited to the above-described embodiments, and can be variously modified in the implementation stage without departing from the scope of the invention. Moreover, each embodiment may be implemented in combination as much as possible, and in that case, the combined effect can be obtained. Furthermore, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the column of effects of the invention is obtained, the configuration from which this constituent element is deleted can be extracted as an invention.

The invention described in the original claims of the present application is added below.
[Claim 1]
From the first closed loop and the second closed loop among at least the first closed loop, the second closed loop and the third closed loop provided corresponding to the pitch, in response to the input of the excitation signal corresponding to the specified pitch generates a string sound signal output from either the left or right channel based on the accumulated signal obtained by accumulating the outputs of
generating a string sound signal output from the other one of the left and right channels based on an accumulated signal obtained by accumulating the outputs of the second closed loop and the third closed loop;
electronic musical instrument.
[Claim 2]
2. The electronic musical instrument according to claim 1, wherein the first closed loop, the second closed loop, and the third closed loop circulate the excitation signal with different delay times.
[Claim 3]
The first closed loop among the first closed loop, the second closed loop, the third closed loop, and the fourth closed loop provided corresponding to the pitch, according to the input of the excitation signal corresponding to the designated pitch, Generating a string sound signal output from one of the left and right channels based on an accumulated signal obtained by accumulating outputs from the second closed loop and the third closed loop,
generating a string sound signal output from either the left or right channel based on an accumulated signal in which outputs from the second closed loop, the third closed loop, and the fourth closed loop are accumulated;
electronic musical instrument.
[Claim 4]
4. The electronic musical instrument according to claim 3, wherein the first closed loop, the second closed loop, the third closed loop, and the fourth closed loop circulate the excitation signal with different delay times.
[Claim 5]
5. The electronic musical instrument according to claim 1, wherein said string sound signal is generated based on said accumulated signal and percussion sound signal.
[Claim 6]
6. An electronic musical instrument as claimed in any one of claims 1 to 5, wherein the excitation signal differs according to a specified velocity.
[Claim 7]
7. A musical tone generation method for causing a computer to execute each process according to any one of claims 1 to 6.
[Claim 8]
A program that causes a computer to execute each process according to any one of claims 1 to 6.

10... Electronic keyboard instrument 11... Keyboard section 12... LSI
12A... CPU
12B... ROM
12C... RAM
12D, 12D'... sound source 12D1... digital signal processor (DSP)
12D2... program memory 12D3... work memory 12E... D/A converter (DAC)
13L, 13R... amplifier (amp.)
14L, 14R speaker 31 note event processing unit 32 waveform reading unit 33 windowing processing unit 34 (for excitation signal generation) waveform memories 35A to 35C gate amplifiers 36A to 36C adders 37A to 37C, 37F... Delay circuits 38A-38C, 38F... Low-pass filters (LPF)
39A to 39C, 39F... attenuation amplifiers 40A, 40C, 40D, 40E, 41A, 41C, 42L, 42R... adders

Claims (8)

From the first closed loop and the second closed loop among at least the first closed loop, the second closed loop and the third closed loop provided corresponding to the pitch, in response to the input of the excitation signal corresponding to the specified pitch generates a string sound signal output from either the left or right channel based on the accumulated signal obtained by accumulating the outputs of
generating a string sound signal output from the other one of the left and right channels based on an accumulated signal obtained by accumulating the outputs of the second closed loop and the third closed loop;
electronic musical instrument. 2. The electronic musical instrument according to claim 1, wherein the first closed loop, the second closed loop, and the third closed loop circulate the excitation signal with different delay times. The first closed loop among the first closed loop, the second closed loop, the third closed loop, and the fourth closed loop provided corresponding to the pitch, according to the input of the excitation signal corresponding to the designated pitch, Generating a string sound signal output from either one of the left and right channels based on an accumulated signal obtained by accumulating outputs from the second closed loop and the third closed loop,
generating a string sound signal output from either the left or right channel based on an accumulated signal in which outputs from the second closed loop, the third closed loop, and the fourth closed loop are accumulated;
electronic musical instrument. 4. The electronic musical instrument according to claim 3, wherein the first closed loop, the second closed loop, the third closed loop, and the fourth closed loop circulate the excitation signal with different delay times. 5. The electronic musical instrument according to claim 1, wherein said string sound signal is generated based on said accumulated signal and percussion sound signal. 6. An electronic musical instrument as claimed in any one of claims 1 to 5, wherein the excitation signal differs according to a specified velocity. 7. A musical tone generating method for causing a computer to execute each process according to any one of claims 1 to 6. A program that causes a computer to execute each process according to any one of claims 1 to 6.

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