JP7567288B2 - ELECTRONIC STRINGED INSTRUMENT, CONTROL METHOD FOR ELECTRONIC STRINGED INSTRUMENT, AND PROGRAM - Google Patents

Description

The present invention relates to an electronic stringed instrument, a control method for an electronic stringed instrument, and a program.

Stringed instruments, including electric guitars, other than electronic instruments that use electronic circuits to generate musical tone waveform signals, can change the tone of the strings by plucking them in different ways and at different positions. For example, if a player holds a soft pick shallowly and picks the strings hard, they can take advantage of the flexibility of the pick and produce a sound that emphasizes the mid- and high-pitched sounds. Also, if a player does not place the pick deeply against the strings, but strokes the tip of the pick forcefully to cut the surface of the string, they can produce a sharp sound that emphasizes the high-pitched sounds. Furthermore, the closer the plucking position is to the center of the strings, the softer (or rounder) guitar sound with fewer overtones will be produced, and the closer the plucking position is to the bridge of the strings, the harder the guitar sound will be produced with more overtones.

Also, there is a known guitar-type electronic stringed instrument that generates harmonic musical tones by detecting a weak touch on the fret controls and a string plucking sensor detecting a string plucking strength above a predetermined value, and generates normal musical tones by detecting pitch data from the fret controls and detecting plucked strings with the string plucking sensor (for example, Patent Document 1).

JP 2004-258434 A

However, in conventional electronic string instruments, while the pitch of the musical tone produced is specified by the fret controls, the string-plucking sensor only detects the timing and intensity (velocity) of the plucked string. This means that it is not possible to subtly change the tone of the musical tone produced by the way or position of the string is plucked, and it is not possible to reflect the nuances of picking, for example, in the musical tone produced.

Therefore, the present invention aims to make it possible to control the musical tones produced by an electronic string instrument depending on how and where the strings are plucked.

an electronic stringed instrument according to one embodiment of the present invention comprises: a string that is strung; a string pluck detection unit that detects the pluck of the string by a player based on string sound waveform data indicating the vibration of the string; a string pluck frequency information calculation unit that calculates plucked frequency information indicating frequency characteristics of the string sound waveform data due to pluck after the string pluck detection unit detects the pluck of the string; a comparison unit that compares the plucked frequency information with pre-stored reference frequency information; a frequency characteristic modification unit that outputs musical sound output data by modifying frequency characteristics of sound source output data output from a sound source unit based on a comparison result of the comparison unit; a pitch designation unit that allows the player to specify a pitch together with the pluck of the string, and generates pitch information indicating the specified pitch; and a sound production control data generation unit that generates sound production control data for controlling generation of the sound source output data based on an intensity of the string sound waveform data at the time when the string pluck detection unit detects the pluck of the string and the pitch information generated by the pitch designation unit, and issues the sound production control data to the sound source unit .

The present invention makes it possible to control the musical tones produced by an electronic stringed instrument depending on how and where the strings are plucked.

FIG. 1 is a front view showing the appearance of an electronic stringed instrument. FIG. 2 is a perspective view showing an example of a neck portion and its internal mechanism. FIG. 2 is a diagram showing an example (entire) of a sensor substrate. FIG. 2A is a diagram showing an example of a sensor substrate (one piece), FIG. 2B is a diagram showing the wiring relationship between the sensor substrate and a control circuit, and FIG. 2C is a diagram showing an example of a pickup. FIG. 2 is a diagram illustrating an example of the hardware configuration of a control circuit of an electronic stringed instrument. FIG. 1 is a block diagram illustrating a first embodiment of an electronic stringed instrument. FIG. 2 is a frequency waveform diagram illustrating the first embodiment of the electronic stringed instrument. FIG. 4 is a frequency waveform diagram showing an example of the frequency characteristics of a band-pass filter in the first embodiment of the electronic stringed instrument. 13 is a flowchart illustrating an example of a main process. 10 is a flowchart showing a detailed example of a plucked string detection process in the first embodiment of the electronic stringed instrument. FIG. 11 is a block diagram illustrating a second embodiment of an electronic stringed instrument. FIG. 11 is a frequency waveform diagram illustrating a second embodiment of an electronic stringed instrument. 10 is a flowchart showing a detailed example of a plucked string detection process in the second embodiment of the electronic stringed instrument. 10 is a flowchart showing a detailed example of a calculation of the i-th string plucked spectral envelope information in the second embodiment of the electronic stringed instrument.

The following describes in detail the embodiment of the present invention (hereinafter referred to as the "present embodiment") with reference to the drawings.

1 is a front view showing the appearance of an electronic stringed instrument 100, and FIG. 2 is a perspective view showing an example of a neck and its internal mechanism. As shown in FIG. 1, the electronic stringed instrument 100 comprises a body 101, a neck 102, and a head 103. The head 103 is fitted with six pegs 110 around which one end of each of six metal strings 111 is wound. Each of the strings 111 wound around each peg 110 is supported by a nut 109 (see FIG. 2) of the head 103, and passes from the neck 102 over the body 101 and is stretched between six supports of a bridge 104 attached to the body 101. Each of the six strings 111 is assigned a string number. The thinnest string 111 at the bottom of the drawing in Figure 1 is the "first string," and the string numbers increase in order of thickness of the strings 111, such as "second string," "third string," "fourth string," "fifth string," and "sixth string."

The neck 102 has a fingerboard 108 attached to its surface, and multiple frets 107 numbered #0 to #N-1 (where N is, for example, 22) are embedded in the fingerboard 108 from the head 103 toward the body 101, so as to run perpendicular to each string 111, as shown in FIG. 2. Each of the N frets 107 is associated with a fret number. The fret 107 closest to the nut 109 of the head 103 is the first fret (or #0 fret), and the frets are numbered sequentially as follows: second fret (#1 fret), third fret (#2 fret), .... The fret 107 closest to the body 101 is the Nth fret (#N-1 fret).

As shown in FIG. 2, inside the neck portion 102, sensor boards 201 #0, #1, ... #N-1 are installed under the fingerboard 108 between the nut 109 and the #0 fret 107, between the #0 and #1 frets 107, ..., between the #N-2 and #N-1 frets 107. In addition, a wiring board 202 is installed in the longitudinal direction inside the neck portion 102, connected to each sensor board 201 and transmitting information from each sensor board 201 to the control circuit 106 (see FIG. 1) installed in the body portion 101.

3 and 4(a) are diagrams showing an example of a sensor board 201. As shown in FIG. 3, six coils 301 for detecting the pressing of each of the six strings 111 are printed on each of the sensor boards 201, #0, #1, ..., #N-1. Also, as shown in FIG. 4(a), for example, in the sensor board 201(#n) at any fret position #n (0≦n≦N-1), between the two terminal wirings of each of the coils 301(#n/#1) to 301(#n/#6) arranged corresponding to each of the strings 111 from the first string to the sixth string, each of the coils 301 is connected to each of the capacitors 401(#n/#1) to 401(#n/#6) for each of the coils 301 to operate as a resonator. Each pair of terminals of each of the coils 301 (#n/#1) to 301 (#n/#6) is connected to the wiring board 202 (see FIG. 2) via a connector 402 (#n), and is connected to the fret sensor interface 506 (see FIG. 5, described later) in the control circuit 106 in the torso 101 via wiring on the wiring board 202. Note that there is a hole in the sensor board 201 corresponding to each center position of each coil 301, and the coil passes through the hole, passes through the back side of the sensor board 201, and is connected to the wiring board 202 (see FIG. 2) via the connector 402 (#n).

Figure 4 (b) is a diagram showing the wiring relationship between the sensor board 201 and the control circuit 106. Each resonant circuit 403 (#n/#i) consisting of each coil 301 (#n/#i) and each capacitor 401 (#n/#i) (1 ≦ i ≦ 6) on each sensor board 201 (#n) (0 ≦ n ≦ N-1) is resonated by each signal supplied from a voltage source in each sensor 404 (#n/#i) arranged in a fret sensor interface 506 (see Figure 5) described later in the control circuit 106 in the body 101 of Figure 1. The sensor 404 (#n/#i) includes a voltage source and a counter that counts the output signal (frequency). When the metal string 111 (#i) approaches the coil 301 (#n/#i), the frequency changes and the count value changes. As a result, each resonant circuit 403 (#n/#i) is resonated at a resonant frequency determined by the inductance value of each coil 301 (#n/#i) and the capacitance value of each capacitor 401 (#n/#i). Now, in a state where a certain resonant circuit 403 (#n/#i) is resonated by a voltage source in a corresponding sensor 404 (#n/#i), the performer presses the metal string 111 (#i) corresponding to the resonant circuit 403 (#n/#i) with his finger on the fingerboard 108 just before the #n fret of the neck 102 (between the #n-1 fret and the #n fret, or between the nut 109 and the #0 fret in FIG. 1 or FIG. 2 when n=0). When this metal string 111 (#i) approaches the coil 301 (#n/#i) in the resonant circuit 403 (#n/#i) (the distance between the string 111 (#i) and the coil 301 (#n/#i) changes), the reactance determined by the coil 301 (#n/#i) and the capacitor 401 (#n/#i) changes. As a result, the voltage across the coil 301 (#n/#i) changes. Therefore, by detecting a voltage change from a change in the count value of a counter that counts the output signal (frequency) in sensor 404 (#n/#i), it is possible to detect that string 111 (#i) has been pressed just before the #n fret.

The sensors 404 (#n/#i) (0≦n≦N-1, 1≦i≦6) may be arranged together in the fret sensor interface 506 (see FIG. 5) described later in the control circuit 106 in the body 101 of FIG. 1 as described above, or may be arranged on the wiring board 202 near the sensor board 201 (#n) to prevent degradation of the analog signal in the resonant circuit 403 (#n/#i).

Here, in the electronic stringed instrument 100 of FIG. 1, it is required to continuously detect the state of pressing (change in distance) of the metal string 111 under the fingerboard 108 in front of all frets 107 from #0 to #N-1. However, in order to do so, it is necessary to make all resonant circuits 403 (#n/#i) (0≦n≦N-1, 1≦i≦6) resonate. However, when one coil 301 (#n/#i) is in a resonant state, if the adjacent coils 301 (#n/#i-1) and 301 (#n/#i+1) resonate at the same time, the magnetic field generated by one coil, for example, 301 (#n/#i), enters another coil 301 (#n/#i-1) or 301 (#n/#i+1), causing electromagnetic induction. The reverse is also possible. As a result, the coils 301(#n/#i), 301(#n/#i-1), and 301(#n/#i+1) interfere with each other, generating noise in the resonant circuits 403(#n/#i), 403(#n/#i-1), and 403(#n/#i+1). This noise reduces the accuracy of detecting the pressing position of the strings 111(#i), 111(#i-1), and 111(#i+1), and in some cases makes detection impossible.

To avoid this, in this embodiment, coils 301 that are close to each other are not driven simultaneously, but are driven in a time-division manner. For example, of the six coils 301 on each sensor board 201, only the coils 301 that are separated by two coils 301 from each other are driven simultaneously during one phase, and the other coils 301 are stopped from resonating. Also, on adjacent sensor boards 201, only the coils 301 that are separated by two coils 301 in the longitudinal direction of the neck portion 102 are driven. Then, by rapidly switching between these phases and resonating each coil 301 in a time-division manner, the pressing position of each string 111 is detected while suppressing interference caused by electromagnetic induction between the coils 301.

In this embodiment, the specific technology for detecting the fingered string position can be the technology described in the following patent document, and therefore a detailed description thereof will be omitted.
(Patent document): Patent No. 6507768

Returning to the explanation of FIG. 1, the body 101 is provided with a bridge 104 to which the other ends of the six strings 111 are attached, and a hexa-divided pickup 105, which is a string vibration sensor that detects the vibration of each string 111 independently. FIG. 4(c) is a diagram showing an example of the hexa-divided pickup 105. As shown in FIG. 1, the hexa-divided pickup 105 is disposed below the six strings 111 at a position slightly away from the bridge 104 on the body 101, and six electromagnetic pickups 410(#i) (1≦i≦6) that detect the vibration of each string 111(#i) are disposed in the case. The string vibrations generated by the player's plucking of each string 111 (#i) are detected as analog electrical signals by the electromagnetic pickup 410 (#i), and as described later in FIG. 5, these analog electrical signals are converted into string sound waveform data 510 (#i) (1≦i≦6) by corresponding A/D (analog/digital) converters (not shown) in the A/D conversion unit 505, and are then processed by the CPU 501.

Figure 5 is a diagram showing an example of the hardware configuration of the control circuit 106 in the body 101 shown in Figure 1. The hardware configuration of the control circuit 106 shown in Figure 5 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, a sound source LSI (Large Scale Integrated Circuit) 504 which is a sound source unit, a fret sensor interface 506, an A/D conversion unit 505, and a D/A converter 507, which are interconnected by a system bus 520. The analog musical tone output signal output by the D/A converter 507 is amplified by an amplifier 508, and then input to a speaker 509 arranged in the body 101 of Figure 1, and is emitted as a musical tone from the speaker 509.

In the above-mentioned connection configuration, the fret sensor interface 506 is connected to the wiring board 202 in FIG. 2, and although not specifically shown, is equipped with hardware (signal resonator and voltage detector) corresponding to the function of the sensor 404 (#n/#i) (0≦n≦N-1, 1≦i≦6) shown in FIG. 5. The fret sensor interface 506 detects the player's fingering positions on the fingerboard 108 by driving this hardware in a time-sharing manner, and notifies the CPU 501 of fingering information 511 indicating those fingering positions.

The A/D conversion unit 505 also receives the vibration state of each string 111 as an electrical signal from each electromagnetic pickup 410 in the hexa-divided pickup 105 shown in Figures 1 and 4(c), and notifies the CPU 501 of each A/D conversion result as each string sound waveform data 510 via each internal A/D converter (not shown).

The CPU 501 executes the control program stored in the ROM 502 while using the RAM 503 as a working memory, thereby executing the control operations of the electronic stringed instrument 100 in Fig. 1. The CPU 501 generates sound generation control data 512 that instructs the sound generation (note on) or sound suppression (note off) of a musical tone with a specified pitch and velocity, based on the string sound waveform data 510 input from the A/D conversion unit 505 and the string pressing information 511 input from the fret sensor interface 506, and issues the sound generation control data 512 to the sound source LSI 504.

The sound source LSI 504 generates sound source output data 513 with an amplitude corresponding to the velocity specified by the sound generation control data 512, for example by reading musical tone waveform data from a waveform ROM (not shown) at a read speed corresponding to the pitch specified by the sound generation control data 512, based on the sound generation control data 512 specified by the CPU 501. The sound source LSI 204 has the ability to generate sound source output data 513 of multiple voices corresponding to the plucked strings of each string 111. This sound source output data 513 is transferred to the RAM 503, for example by DMA (direct memory access), as shown by the dashed line in FIG. 5.

The CPU 501 reads the sound source output data 513 from the RAM 503 as shown by the dashed line in Fig. 5, and executes a frequency characteristic change process on the sound source output data 513 based on the string sound waveform data 510 input from the A/D conversion unit 505, the string pressing information 511 input from the fret sensor interface 506, and the reference spectrum information (in the case of the first embodiment of the electronic string instrument 100) or the reference spectrum envelope information (in the case of the second embodiment of the electronic string instrument 100) read from the ROM 502. The CPU 501 transfers the resulting musical tone output data 514 (dashed line portion in Fig. 5) to a specified storage area on the RAM 503 as shown by the dashed line in Fig. 5.

The musical tone output data 514 transferred to the RAM 503 is further transferred, for example, by DMA to the D/A converter 507, as shown by the dashed line in FIG. 5. The D/A converter 507 converts the digital musical tone output data 514 into an analog musical tone signal and outputs it to the amplifier 508.

The operation of the first embodiment of the electronic stringed instrument 100 having the configuration shown in Figures 1 to 5 above will now be described. A player (e.g., a right-handed player) holds the body 101 of the electronic stringed instrument 100 shown in Figure 1 with his right arm, places his left hand on the neck 102, and presses one or more fingering positions (desired strings 111 at desired frets 107) on the fingerboard 108, and then plucks each of the strings 111 corresponding to each fingering position with a pick or the like held in his right hand, thereby performing a performance. This operation is the same as that when playing a normal guitar.

At this time, as described above, the fret sensor interface 506 detects each of the pressing positions by driving each of the resonant circuits 403 (see Figures 4(a) and (b)) in a time-division manner from each of the sensors 404 in the fret sensor interface 506 that correspond to each of the pressing positions, thereby detecting each of the pressing information 511 corresponding to each of the pressing positions. Then, this pressing information 511 is notified to the CPU 501.

Meanwhile, the A/D conversion unit 505 detects the state of each string 111 as each string sound waveform data 510 from each electromagnetic pickup 410 in the hexa-divided pickup 105 shown in Figures 1 and 4(c) via each internal A/D converter (not shown). Then, this string sound waveform data 510 is notified to the CPU 501.

Figure 6 is a functional block diagram showing the control process executed by the CPU 501 in Figure 5 in the first embodiment of the electronic stringed instrument 100, based on string sound waveform data 510 for each string 111 and corresponding string pressing information 511. In reality, the process corresponding to the configuration in Figure 6 is executed in parallel for each of the six strings 111 (#i) (1 ≤ i ≤ 6) by time-sharing processing.

In FIG. 6, the plucking detection unit 601, which is a function of the CPU 501 executing the control program, detects the plucking operation of the string 111 currently being processed in time-sharing by the player based on the string sound waveform data 510 detected via the A/D conversion unit 505 in FIG. 5 from the electromagnetic pickup 410 (see FIG. 4(c)) corresponding to the string 111 currently being processed in time-sharing in the hexadivided pickup 105. When the plucking detection unit 601 detects the plucking operation corresponding to the string 111 currently being processed in time-sharing, it calculates the strength 620 of the plucking operation and outputs it to the sound generation control data generation unit 603.

In FIG. 6, the string pressing information 511 output from the fret sensor interface 506 is input to a pitch determination unit 602, which is a function that causes the CPU 501 to execute a control program. Based on the input string pressing information 511, the pitch determination unit 602 determines which fret 107 is being pressed for the string 111 currently being time-shared, and determines the pitch specified by the performer based on which string 111 is and the fret 107 position indicated by the string pressing information 511, and outputs the determined pitch information 621.

In FIG. 6, the sound generation control data generation unit 603, which is a function of the CPU 501 executing the control program, generates sound generation control data 512 to instruct the generation (note on) or muting (note off) of sound source output data 513 based on the intensity 620 of the string sound waveform data 510 at the timing when the plucking detection unit 601 detects the plucking of the string 111 and the pitch information 621 generated by the pitch determination unit 602, and issues the data to the sound source LSI 504.

Here, the storage unit, for example, ROM 502 in FIG. 5, stores, as reference frequency information, multiple sets of reference spectrum information that indicate frequency spectrum characteristics of string sound waveform data that correspond to multiple pitches and serve as a reference for any plucking operation on the string 111. This reference spectrum information is prepared, for example, for each of the six strings 111 and for each pitch corresponding to each fret 107 on the fingerboard 108, and stored in the ROM 502. In addition, it is preferable for this reference spectrum information to be a standard spectrum characteristic obtained by plucking, for example, the center part (near the 12th fret) of the string 111 that is stretched, but it may also be information that corresponds to various plucking forms (methods of plucking such as picking and positions at which the string is plucked) as appropriate.

In FIG. 6, the plucked string spectrum information calculation unit 604 (plucked string frequency information calculation unit), which is a function of the CPU 501 executing the control program, calculates the plucked string spectrum information 622 (plucked string frequency information) that indicates the frequency spectrum characteristics due to plucking of the string sound waveform data 510, for example, by using a fast Fourier transform.

In FIG. 6, the reference spectrum information reading unit 605, which is a function of the CPU 501 executing the control program, reads reference spectrum information 623 corresponding to the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 and corresponding to the string 111 currently being time-division processed, for example from the ROM 502 in FIG. 5 to the RAM 503.

In FIG. 6, the differential spectrum information calculation unit 606 (comparison unit), which is a function in which the CPU 501 executes a control program, calculates differential spectrum information 624 by subtracting the maximum or average value of the pitch-corresponding frequency or its neighboring frequency in the reference spectrum information 623 from the maximum or average value of the pitch-corresponding frequency or its neighboring frequency in the plucked string spectrum information 622 for each pitch-corresponding frequency, which is the fundamental frequency corresponding to the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 or a predetermined number of harmonic frequencies that are a natural number multiple of twice or more of the fundamental frequency.

7(a) shows an example of the waveform of the plucked string spectrum information 622, and FIG. 7(b) shows an example of the waveform of the reference spectrum information 623 corresponding to the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 in response to the plucked string spectrum information 622. Both figures have a comb-shaped frequency characteristic with large spectral values at the fundamental frequency corresponding to the pitch indicated by the pitch information 621 or a predetermined number of harmonic frequencies that are a natural number multiple of at least twice the fundamental frequency, but it can be seen that the plucked string spectrum information 622 at the time of actual plucking has a different balance of spectral values at the fundamental frequency corresponding to the pitch indicated by the pitch information 621 or a predetermined number of harmonic frequencies that are a natural number multiple of at least twice the fundamental frequency, compared to the reference spectrum information 623. Here, the sound source output data 513 output from the sound source LSI 504 in response to the pitch indicated by the pitch information 621 and corresponding to the string 111 currently being time-shared is tuned to be generated assuming a frequency characteristic corresponding to the reference spectrum information 623. Therefore, in the first embodiment of the electronic string instrument 100, by calculating difference spectrum information 624 of the plucked string spectrum information 622 with respect to the reference spectrum information 623 for each fundamental frequency corresponding to the pitch indicated by the pitch information 621 or for each predetermined number of harmonic frequencies that are a natural number multiple of twice or more the fundamental frequency, it is possible to extract the difference between the plucked string spectrum information 622 calculated during actual plucking and the reference spectrum information 623.

In FIG. 6, the bandpass filter units 608 #0 to #5 that input the sound source output data 513 from the sound source LSI 504, which are functions of the CPU 501 executing the control program, and the mixer unit 609 that mixes the output of each bandpass filter unit 608 and outputs it as musical sound output data 514, operate as a frequency characteristic change unit that outputs musical sound output data 514 by changing the frequency characteristics of the sound source output data 513 output from the sound source LSI 504 based on the differential spectrum information 624 (comparison result) calculated by the differential spectrum information calculation unit 606 (comparison unit).

In this case, in FIG. 6, the bandpass filter setting unit 607, which is a function of the CPU 501 executing the control program, sets each of the predetermined pitch-corresponding frequencies described above as the center frequency 625 in each bandpass filter unit 608. In addition, the bandpass filter setting unit 607 sets each gain 626 corresponding to the value of each difference spectrum information 624 corresponding to each of the predetermined pitch-corresponding frequencies described above in each bandpass filter unit 608.

Figure 8 is a frequency waveform diagram showing an example of the frequency characteristics of each band-pass filter section 608 set as described above in the first embodiment of the electronic stringed instrument 100. Here, for example, it is assumed that the pitch corresponding to the pitch information 621 determined by the pitch determination section 602 in Figure 6 is 110 Hz.

In this case, in the bandpass filter section 608 (#0), the pitch corresponding frequency = 110 Hz, which is the fundamental frequency equal to the frequency of the above pitch, is set as the center frequency 625, and the gain 626 corresponding to the value of the difference spectrum information 624 at the frequency of 110 Hz is set. In Figure 8, the gain curves of each bandpass filter section 608 are drawn in various changes, indicating that the gain characteristics of the bandpass filter vary in various ways depending on the gain 626 set by the bandpass filter setting section 607.

In FIG. 8, in the bandpass filter section 608 (#1), the pitch-corresponding frequency, which is twice the frequency of the above pitch, of 220 Hz is set as the center frequency 625, and a gain 626 is set that corresponds to the value of the difference spectrum information 624 at the frequency 220 Hz.

In FIG. 8, in the bandpass filter section 608 (#2), the pitch-corresponding frequency, which is the fourth harmonic of the above pitch frequency, of 440 Hz is set as the center frequency 625, and a gain 626 is set that corresponds to the value of the difference spectrum information 624 at the frequency of 440 Hz.

In FIG. 8, in the bandpass filter section 608 (#3), the pitch-corresponding frequency, which is the eighth harmonic of the above pitch frequency, 880 Hz, is set as the center frequency 625, and the gain 626 is set corresponding to the value of the difference spectrum information 624 at the frequency 880 Hz.

In FIG. 8, in the bandpass filter section 608 (#4), the pitch-corresponding frequency, which is 16 overtones of the above pitch frequency, of 1760 Hz is set as the center frequency 625, and a gain 626 is set that corresponds to the value of the difference spectrum information 624 at the frequency 1760 Hz.

In FIG. 8, in the bandpass filter section 608 (#5), the pitch-corresponding frequency, which is the 32nd harmonic of the above pitch frequency, 3520 Hz, is set as the center frequency 625, and a gain 626 is set that corresponds to the value of the difference spectrum information 624 at the frequency 3520 Hz.

As described above in FIG. 6, in the first embodiment of the electronic string instrument 100, for the string 111 currently undergoing time-sharing processing, for each pitch-corresponding frequency which is the fundamental frequency corresponding to the pitch indicated by the pitch information 621 determined by the pitch determination unit 602 or a predetermined number of harmonic frequencies which are a natural number multiple of twice or more the fundamental frequency, the frequency characteristics of the sound source output data 513 input from the sound source LSI 504 via RAM 503 can be changed by, for example, six bandpass filter units 608, #0 to #5, based on the difference spectrum information 624, which is the result of comparing the plucked string spectrum information 622 with the reference spectrum information 623, and the data can be output as musical sound output data 514. As a result, just like with a non-electronic string instrument such as an electric guitar, depending on how and where the string 111 is plucked, the plucked string spectrum information 622, which is the frequency characteristic of the vibration of the string 111, changes from the reference spectrum information 623. The tone of the sound source output data 513 output by the sound source LSI 504 can be changed by, for example, six bandpass filter sections 608, #0 to #5, to the extent that this is output as musical tone output data 514.

For example, when a performer holds a soft pick shallowly and picks the string 111 strongly, musical tone output data 514 that emphasizes the mid-high range can be outputted compared to the reference sound source output data 513. Also, when a performer does not touch the string 111 deeply with the pick, but strokes the string surface with the tip of the pick forcefully, musical tone output data 514 that emphasizes the high range can be outputted compared to the reference sound source output data 513. Furthermore, when the string 111 is plucked at a position close to the center, musical tone output data 514 with a small gain 626 of each harmonic component that is more than twice as large as the reference sound source output data 513 and a soft (or so-called round) sound can be outputted. When the string 111 is plucked at a position close to the bridge portion 104 (see FIG. 1 ) of the string 111, musical tone output data 514 with a large gain 626 of each harmonic component that is more than twice as large as the reference sound source output data 513 and a hard sound can be outputted.

Figure 9 is a flow chart showing an example of a main process executed by the control circuit 106 in Figure 1 to realize the operation of the first embodiment of the electronic stringed instrument 100. This process is an operation in which the CPU 501 in the control circuit 106 in Figure 5 loads the control program stored in the ROM 502 into the RAM 503 and executes it.

First, when the power is turned on, the CPU 501 executes an initialization process for the contents stored in the RAM 503 (step S901).

After that, the CPU 501 repeatedly executes the series of processes from steps S902 to S905 until the power is turned off.

In the above repeat process, first, the CPU 501 executes a switch process (step S902). In step S902, when the performer turns on any of the tone switches (not shown) arranged on the body 101 in FIG. 1, the CPU 501 issues to the sound source LSI 504 the tone setting event, sound generation control data 512, which is a tone setting event with a tone number corresponding to the tone specified by the tone switch. As a result, the sound source LSI 504 changes the tone of the generated sound source output data 513. Also, in step S902, when the performer turns the volume knob (not shown) arranged on the body 101, the CPU 501 sets the amplification factor specified by the volume knob to the amplifier 508 in FIG. 5.

Next, the CPU 501 executes a pluck detection process (step S903). Here, the CPU 501 detects which string 111 has been plucked by the hexa-divided pickup 105 (see FIG. 1) and which fret position of the plucked string 111 has been pressed. Details of this process will be described later using the flowchart in FIG. 10.

Next, the CPU 501 executes sound generation processing (step S904). Here, the CPU 501 issues sound generation control data 512 to the sound source LSI 504 based on the result of the plucked string detection processing in step S903. As a result, the sound source LSI 504 generates and outputs sound source output data 513, or mutes sound.

Finally, the CPU 501 executes other processes (step S905). Here, the CPU 501 executes various processes necessary for controlling the electronic stringed instrument 100 that were not executed in steps S902, S903, and S904. After that, the CPU 501 returns to the process of step S902.

Figure 10 is a flow chart showing a detailed example of the plucked string detection process in step S903 in Figure 9 in the first embodiment of the electronic stringed instrument. In Figure 10, the CPU 501 repeatedly executes the series of control processes from step S1002 to S1014 while changing the value of variable i stored in the RAM 503 from the value "1" (step S1001) by +1 (step S1015) until it is determined that the value has exceeded "6" (step S1016) in order to execute time-division processing for each of the six strings 111 (#i) (1 ≤ i ≤ 6).

In the above series of processes, the string sound waveform data 510 of the i-th string is obtained from the electromagnetic pickup 410 (#i) (see FIG. 4(c)) corresponding to the string 111 (#i) (hereinafter referred to as the "i-th string") currently being time-shared, the number of which is indicated by the value of the variable i in the hexa-divided pickup 105, via the A/D converter 505 in FIG. 5 (step S1002).

Next, the CPU 501 determines whether a new plucking of the i-th string by the player has been detected (step S1003). In this determination, the CPU 501 detects a new plucking of the i-th string by the player, for example, by determining whether the amplitude of the string sound waveform data 510 of the i-th string acquired in step S1002 was equal to or less than a predetermined plucking judgment threshold in the previous determination in step S1003, and exceeded the plucking judgment threshold in the current determination in step S1003.

If the determination in step S1003 is YES, the CPU 501 calculates the strength 620 (see FIG. 6) of the plucking action of the i-th string by the player based on, for example, the average value of the amplitude of the string sound waveform data 510 acquired in step S1002 over a predetermined period of time.

The above processing in steps S1003 and S1004 corresponds to the function of the plucked string detection unit 601 in FIG. 6.

Next, the CPU 501 determines the pitch designated by the performer by determining which fret 107 on the fingerboard 108 is being pressed for the i-th string based on the string pressing information 511 input from the fret sensor interface 506, and determines the determined pitch information 621 (step S1005). This process corresponds to the function of the pitch determination unit 602 in FIG. 6.

Next, the CPU 501 generates sound generation control data 512 instructing sound generation (note-on) based on the plucking strength 620 of the i-th string calculated in step S1004 at the timing when the plucking of the i-th string was detected in step S1003 and the pitch information 621 corresponding to the i-th string calculated in step S1005, and stores the data in the RAM 503 (step S1006). The CPU 501 reads the sound generation control data 512 generated in step S1006 from the RAM 503 in step S904 in FIG. 9 described above and issues the data to the sound source LSI 504. The above processing in step S1006 and step S904 in FIG. 9 corresponds to the note-on instruction function of the sound generation control data generation unit 603 in FIG. 6.

On the other hand, if a new plucking of the i-th string by the player is not detected and the determination in step S1003 is NO, the CPU 501 determines in step S1007 whether the i-th string is already being plucked (step S1007). In this process, the CPU 501 determines whether the amplitude of the string sound waveform data 510 acquired in step S1002, for example, exceeds the predetermined plucking determination threshold value described above.

If the i-th string is no longer being plucked and the determination in step S1007 is NO, the CPU 501 further determines whether the sound source LSI 504 is generating sound source output data 513 corresponding to the i-th string (step S1008).

If the determination in step S1008 is YES, the CPU 501 generates sound generation control data 512 that instructs muting (note off) the sound source output data 513 corresponding to the i-th string, and stores it in the RAM 503 (step S1009). The CPU 501 reads the sound generation control data 512 generated in step S1009 from the RAM 503 in step S904 of FIG. 9 described above, and issues it to the sound source LSI 504. The CPU 501 then proceeds to the process of step S1015.

If the i-th string is still being plucked and the determination in step S1007 is YES, or if the i-th string is no longer being plucked and the sound source LSI 504 has already muted the sound source output data 513 corresponding to the i-th string and the determination in step S1008 is NO, the CPU 501 skips the generation process of the sound generation control data 512 in step S1009 and proceeds to the process of step S1015.

The above series of processes from step S1007 to S1009 and the process of step S904 in FIG. 9 correspond to the note-off instruction function of the sound generation control data generation unit 603 in FIG. 6.

After generating the sound generation control data 512 instructing sound generation (note-on) in step S1006 described above, the CPU 501 performs, for example, a Fast Fourier Transform (FFT) operation on the string sound waveform data 510 of the i-th string for a predetermined period from the start of plucking, acquired in step S1002, to calculate the i-th string plucked spectrum information 622 indicating the frequency spectrum characteristics due to the plucking of the i-th string (step S1010). This process corresponds to the function of the plucked string spectrum information calculation unit 604 in FIG. 6.

Next, the CPU 501 reads the reference spectrum information 623 corresponding to the pitch indicated by the pitch information 621 determined in step S1005 and corresponding to the i-th string from the ROM 502 to the RAM 503 (step S1011). This process corresponds to the function of the reference spectrum information reading unit 605 in FIG. 6.

Furthermore, for each pitch-corresponding frequency corresponding to the pitch indicated by the pitch information 621 determined in step S1005 (see FIG. 8), the CPU 501 calculates the i-th string difference spectrum information 624 by subtracting the maximum or average value at the pitch-corresponding frequency or its nearby frequency of the reference spectrum information 623 loaded into the RAM 503 in step S1011 from the maximum or average value at the pitch-corresponding frequency or its nearby frequency of the plucked string spectrum information 622 obtained in step S1010 (step S1012). This process corresponds to the function of the difference spectrum information calculation unit 606 in FIG. 6.

Then, the CPU 501 sets each of the pitch-corresponding frequencies (see FIG. 8) described above as the center frequencies 625 in the execution programs for the time-division bandpass filter calculation process and the mixer calculation process expanded on the RAM 503 corresponding to the bandpass filter units 608 #0 to #5 and the mixer unit 609 (see FIG. 6) (step S1013), and also sets each gain 626 corresponding to the value of each difference spectrum information 624 corresponding to each of the pitch-corresponding frequencies described above calculated in step S1012 (step S1014). These processes correspond to the function of the bandpass filter setting unit 607 in FIG. 6.

The above series of steps S1002 to S1014 are executed as time-division processing for six strings 111. As a result, depending on the way and position of the player plucking each of the i-th strings 111 (1≦i≦6), the plucked string spectrum information 622, which is the frequency characteristic of the vibration of the i-th string, changes from the reference spectrum information 623 of the i-th string, and the tone of the sound source output data 513 corresponding to the i-th string input from the sound source LSI 504 via the RAM 503 can be changed by, for example, six band-pass filter calculations (corresponding to the band-pass filter units 608 #0 to #5 in FIG. 6) performed by time-division processing, and musical tone output data 514 corresponding to the i-th string can be output.

The operation of the second embodiment of the electronic stringed instrument 100 having the configuration shown in Figures 1 to 5 described above will now be described.

Figure 11 is a functional block diagram showing the control process executed by the CPU 501 in Figure 5 in the second embodiment of the electronic stringed instrument 100, based on string sound waveform data 510 for each string 111 and string pressing information 511. In reality, the process corresponding to the configuration in Figure 11 is executed in parallel for each of the six strings 111 (#i) (1 ≤ i ≤ 6) by time-sharing.

The configuration of FIG. 11 corresponding to the embodiment of the electronic stringed instrument 100 differs from the configuration of FIG. 6 corresponding to the first embodiment of the electronic stringed instrument 100 in that spectral envelope information is used instead of spectral information. The spectral envelope information is a frequency characteristic obtained by removing a comb-shaped frequency structure of a fundamental frequency corresponding to the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 from the spectral information or a predetermined number of harmonic frequencies that are a natural number multiple of twice or more the fundamental frequency, and has the advantage that the pitch information 621 does not need to be taken into consideration when executing a process of changing the frequency characteristic of the sound source output data 513 output from the sound source LSI 504 and outputting the musical tone output data 514.

In FIG. 11, the functions represented by the plucking detection unit 601, the pitch determination unit 602, and the sound generation control data generation unit 603, which are functions by which the CPU 501 executes the control program, are the same as those in FIG. 6.

For example, the ROM 502 in FIG. 5 , which is a storage unit, stores reference spectrum envelope information indicating the frequency spectrum envelope characteristics that are the reference for the string sound waveform data corresponding to any plucking operation on the string 111 as reference frequency information. This reference spectrum envelope information is prepared, for example, for each of the six strings 111 individually and stored in the ROM 502. Unlike the first embodiment of the electronic string instrument 100, in the second embodiment of the electronic string instrument 100, the reference spectrum envelope information does not need to be prepared individually for each pitch, but since the timbre of the reference musical tone may differ when the pitch differs greatly, the reference spectrum envelope information may be prepared for each group of large pitches. As in the first embodiment of the electronic string instrument 100, this reference spectrum envelope information is preferably a standard spectrum envelope characteristic obtained by plucking, for example, the center part (near the 12th fret) of the string 111 that is stretched, but may be information that corresponds to various plucking forms (plucking methods such as picking and plucking positions) as appropriate.

In FIG. 11, the plucked string spectrum envelope information calculation unit 1101 (plucked string frequency information calculation unit), which is a function of the CPU 501 executing the control program, calculates plucked string spectrum envelope information 1110 (plucked string frequency information) that indicates the frequency spectrum envelope characteristics due to plucking of the string sound waveform data 510, for example, by cepstrum analysis calculation.

In FIG. 11, the reference spectral envelope information reading unit 1102, which is a function of the CPU 501 executing a control program, reads the reference spectral envelope information 1111 corresponding to the string 111, for example, from the ROM 502 in FIG. 5 into the RAM 503. Note that, if the reference spectral envelope information 1111 is prepared for each major pitch group as described above, the reference spectral envelope information reading unit 1102 may read the reference spectral envelope information 1111 corresponding to that group, for example, from the ROM 502 in FIG. 5 into the RAM 503, depending on which major pitch group the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 is included in.

11, the difference spectrum envelope information calculation unit 1103 (comparison unit), which is a function of the CPU 501 executing a control program, calculates the difference spectrum envelope information 1112 by subtracting the value of the reference spectrum envelope information 1111 from the value of the plucked string spectrum envelope information 1110 at a predetermined frequency interval (e.g., for each frequency point of the fast Fourier transform). In the second embodiment of the electronic string instrument 100, unlike the first embodiment of the electronic string instrument 100, it is not necessary to perform calculations for each pitch-corresponding frequency, which is the fundamental frequency corresponding to the pitch indicated by the pitch information 621 generated by the pitch determination unit 602 or a predetermined number of harmonic frequencies that are a natural number multiple of twice or more the fundamental frequency.

Fig. 12(a) is a diagram showing an example waveform of plucked string spectrum envelope information 1110. As shown as 1201 in Fig. 12(a) , the plucked string spectrum envelope information 1110 in Fig. 11 is a frequency envelope characteristic obtained by removing the influence of the comb-shaped frequency structure caused by the fundamental frequency corresponding to the pitch indicated by pitch information 621 or a predetermined number of harmonic frequencies that are a natural number multiple of twice or more the fundamental frequency from the plucked string spectrum information 622 in Fig. 6 shown as 1202 in Fig. 12(a) (corresponding to the waveform diagram in Fig. 7(a)).

On the other hand, Fig. 12(b) is a diagram showing example waveforms of the reference spectrum envelope information 1111 and the plucked string spectrum envelope information 1110. The reference spectrum envelope information 1111 in Fig. 11 is a frequency envelope characteristic obtained by removing the influence of the comb-shaped frequency structure caused by the fundamental frequency corresponding to the pitch indicated by the pitch information 621 or a predetermined number of harmonic frequencies that are a natural number multiple of twice or more the fundamental frequency, from the reference spectrum information 623 in Fig. 6 shown as 1204 in Fig. 12(b) (corresponding to the waveform diagram in Fig. 7(b)), as shown as 1203 in Fig. 12(b).

The difference spectrum envelope information 1112 in FIG. 11 has characteristics obtained by subtracting the reference spectrum envelope information 1111 shown as 1203 in FIG. 12(b) from the plucked string spectrum envelope information 1110 shown as 1201 in FIG. 12(b) (the same as 1201 in FIG. 12(a)) at a predetermined frequency interval, as shown by the upward arrow (when the plucked string spectrum envelope information 1110>the reference spectrum envelope information 1111) or the downward arrow (when the plucked string spectrum envelope information 1110<the reference spectrum envelope information 1111) in 1205 in FIG. 12(b).

As can be seen by comparing 1201 and 1203 in FIG. 12(b), the plucked string spectrum envelope information 1110 during actual plucking has a different balance of spectral envelope values compared to the reference spectrum envelope information 1111. Here, the sound source output data 513 output from the sound source LSI 504 corresponding to the string 111 currently being time-shared and corresponding to the pitch indicated by the pitch information 621 is tuned to be generated assuming a frequency characteristic corresponding to the reference spectrum envelope information 1111. Therefore, in the second embodiment of the electronic stringed instrument 100, by calculating the difference spectrum envelope information 1112 of the plucked string spectrum envelope information 1110 with respect to the reference spectrum envelope information 1111, it is possible to extract the difference between the plucked string spectrum envelope information 1110 calculated during actual plucking and the reference spectrum envelope information 1111.

Furthermore, in the second embodiment of the electronic string instrument 100, unlike the first embodiment of the electronic string instrument 100, there is no need to take into account differences in pitch due to the pitch information 621, so the number of sets of reference spectral envelope information 1111 pre-stored in the ROM 502 can be significantly reduced compared to the number of sets of reference spectral information 623 in the first embodiment of the electronic string instrument 100, which has the advantage that it is only necessary to prepare a ROM 502 with a small storage capacity.

In FIG. 11, the difference spectrum envelope information impulse response calculation unit 1104, which is a function in which the CPU 501 executes a control program, calculates the difference spectrum envelope information impulse response 1113, which is a time domain impulse response corresponding to the difference spectrum envelope information 1112, by, for example, adding an offset value (a value that makes the transfer function 1 when viewed as a filter) to each frequency amplitude of the difference spectrum for the difference spectrum envelope information 1112 calculated by the difference spectrum envelope information calculation unit 1103 to make all frequency amplitudes positive, and then performing a fast inverse Fourier transform.

Furthermore, in FIG. 11, the convolution filter unit 1105, which is a function in which the CPU 501 executes a control program, executes a convolution operation in which the differential spectrum envelope information impulse response 1113 calculated by the differential spectrum envelope information impulse response calculation unit 1104 is convolved in the time domain with the sound source output data 513 input from the sound source LSI 504 via the RAM 503, thereby outputting musical tone output data 514.

This convolution operation filter unit 1105 operates as a frequency characteristic change unit that changes the frequency of the sound source output data 513 having frequency envelope characteristics corresponding to the reference spectrum envelope information 1111 shown as 1203 in FIG. 12(b) to a frequency corresponding to the difference spectrum envelope information 1112 (comparison result) shown as 1205 in FIG. 12(b). This convolution operation filter unit 1105 can then generate musical sound output data 514 having frequency envelope characteristics corresponding to the performer's actual plucking of the strings, which corresponds to the plucking spectrum envelope information 1110 shown as 1201 in FIG. 12(b).

As described above, in the second embodiment of the electronic string instrument 100, as described in FIG. 11, for the string 111 currently undergoing time-sharing processing, the convolution operation filter unit 1105 can change the frequency characteristics of the sound source output data 513 input from the sound source LSI 504 via the RAM 503 based on the differential spectrum envelope information 1112, which is the result of comparing the plucked string spectrum envelope information 1110 with the reference spectrum envelope information 1111, and its impulse response, the differential spectrum envelope information impulse response 1113, and output it as musical sound output data 514. As a result, just like with a non-electronic string instrument such as an electric guitar, the plucked string spectrum envelope information 1110, which is the frequency characteristic of the vibration of the string 111, changes from the reference spectrum envelope information 1111 depending on the way and position of the string 111 being plucked, and the convolution filter unit 1105 changes the tone of the sound source output data 513 output by the sound source LSI 504 to the extent that it is output as musical tone output data 514.

Next, the process executed by the control circuit 106 in FIG. 1 to realize the operation of the above-mentioned second embodiment of the electronic stringed instrument 100 will be described. As in the first embodiment of the electronic stringed instrument 100, this process is an operation in which the CPU 501 in the control circuit 106 in FIG. 5 loads a control program stored in the ROM 502 into the RAM 503 and executes it.

First, in the second embodiment of the electronic stringed instrument 100, an example of the main processing executed by the CPU 501 is the same as the flowchart of FIG. 9 described in the first embodiment of the electronic stringed instrument 100.

Figure 13 is a flowchart showing a detailed example of the plucked string detection process in step S903 of Figure 9 in the second embodiment of the electronic stringed instrument 100. In the flowchart of Figure 13, the processes given the same step numbers as those in the flowchart of Figure 10, which shows a detailed example of the plucked string detection process in the first embodiment of the electronic stringed instrument 100, execute the same processes as in the first embodiment.

In FIG. 13, the CPU 501 repeatedly executes a series of control processes from steps S1003 to S1009 and steps S1301 to S1305 while incrementing the value of the variable i stored in the RAM 503 by +1 (step S1015) from the value "1" (step S1001) until it determines that the value has exceeded "6" (step S1016), in order to execute time-division processing for each of the six strings 111 (#i) (1≦i≦6), just as in the case of FIG. 10 in the first embodiment of the electronic stringed instrument 100.

In the above series of processes, the series of processes from step S1002 to step S1009 are the same as those in FIG. 10 for the first embodiment of the electronic stringed instrument 100. The series of processes that follow, from step S1301 to step S1305, will be described below.

First, the CPU 501 performs, for example, a cepstrum calculation on the string sound waveform data 510 of the i-th string acquired in step S1002 to calculate the i-th string plucked spectrum envelope information 1110 indicating the frequency spectrum envelope characteristics due to the pluck of the i-th string (step S1301). This process corresponds to the function of the plucked string spectrum envelope information calculation unit 1101 in FIG. 11.

Figure 14 is a flowchart showing a detailed example of the calculation of the i-th string plucked spectrum envelope information in step S1301 in Figure 13. First, the CPU 501 calculates the i-th string plucked spectrum information indicating the frequency spectrum characteristics due to the pluck of the i-th string by, for example, performing a fast Fourier transform calculation on the string sound waveform data 510 of the i-th string acquired in step S1002 (step S1401). This process is the same as the process in step S1010 in Figure 10 in the first embodiment of the electronic stringed instrument 100.

Next, the CPU 501 calculates the logarithm of the spectrum value for each frequency point of the i-th string plucked spectrum information calculated in step S1401, thereby calculating the i-th string plucked logarithmic spectrum information (step S1402).

Next, the CPU 501 calculates the i-th string plucked cepstrum information, which is a physical quantity in the quefrency domain, by, for example, performing an inverse fast Fourier transform on the i-th string plucked logarithmic spectrum information calculated in step S1402 (step S1403).

The CPU 501 further executes an i-th string plucked string liftering operation, which is a liftering operation that leaves only values in the low-frequency quefrency region below a predetermined threshold in the i-th string plucked string cepstrum information of the quefrency region calculated in step S1403, and sets all values in the high-frequency quefrency region above the threshold to zero (step S1404).

Then, the CPU 501 calculates the i-th string plucked spectrum envelope information 1110 in FIG. 11 by, for example, performing a fast Fourier transform on the i-th string plucked cepstrum information including the zero values after the liftering calculation calculated as a result of the calculation in step S1404 (step S1405). After that, the CPU 501 ends the i-th string plucked spectrum envelope information calculation process in step S1301 in FIG. 13 shown in the flowchart in FIG. 14.

Returning to the explanation of the flowchart in FIG. 13, the CPU 501 then reads the reference spectral envelope information 1111 corresponding to the i-th string from the ROM 502 into the RAM 503 (step S1302). This process corresponds to the function of the reference spectral envelope information reading unit 1102 in FIG. 11.

Furthermore, at a predetermined frequency interval (e.g., at each frequency point of the fast Fourier transform), the CPU 501 calculates the i-th string difference spectrum envelope information 1112 by subtracting the value of the reference spectrum envelope information 1111 loaded into the RAM 503 in step S1302 from the value of the plucked string spectrum envelope information 1110 obtained in step S1301 (step S1303). This process corresponds to the function of the difference spectrum envelope information calculation unit 1103 in FIG. 11.

Then, the CPU 501 performs, for example, a fast inverse Fourier transform on the difference spectrum envelope information 1112 calculated in step S1303 to calculate a difference spectrum envelope information impulse response 1113, which is a time domain impulse response corresponding to the difference spectrum envelope information 1112 (step S1304). This process corresponds to the function of the difference spectrum envelope information impulse response calculation unit 1104 in FIG. 11.

Then, the CPU 501 sets the difference spectrum envelope information impulse response 1113 calculated in step S1304 in the execution program for the time-division convolution filter processing expanded on the RAM 503 (step S1305). This processing corresponds to the function of the convolution filter unit 1105 in FIG. 11.

The above series of steps S1002 to S1009 and steps S1301 to S1305 are executed as time-division processing for six strings 111. As a result, depending on the manner and position of the player's plucking of each of the i-th strings 111 (1≦i≦6), the plucked string spectrum envelope information 1110, which is the frequency characteristic of the vibration of the i-th string, changes from the reference spectrum envelope information 1111, and the convolution operation filter unit 1105 changes the tone of the sound source output data 513 corresponding to the i-th string output by the sound source LSI 504 to output musical tone output data 514 corresponding to the i-th string.

In the first and second embodiments of the electronic stringed instrument 100 described above, the resonant circuit 403 (see FIGS. 4(a) and (b)) arranged on the sensor board 201 having the configurations of FIGS. 2, 3, and 4(a) and (b) is driven in a time-division manner by the sensor 404 in the fret sensor interface 506 in FIG. 5 to detect the pressing information 511 corresponding to the pressing position of the string on the fingerboard 108 by the player, and the pitch determination unit 602 in FIG. 6 or FIG. 11 determines the pitch based on the pressing information 511. As another embodiment, a pitch extraction calculation may be performed on the string sound waveform data 510 of each string 111 detected from the hexa-divided pickup 105 in FIG. 1 or FIG. 4(c) via the A/D conversion unit 505 in FIG. 5 in response to the pressing operation of the string 111 performed by the player on the fingerboard 108 together with the plucking operation of the string 111, and the pitch specified by the player may be determined based on the pitch calculated by the pitch extraction calculation.

In another embodiment, the string pressed on the fingerboard 108 and the string whose vibration is detected by the hexa-divided pickup 105 may be different strings.

In another embodiment, the fingerboard 108 does not necessarily require frets 107, and the first or second embodiment of the electronic stringed instrument 100 may be applied to a violin, bass guitar, or the like.

In the second embodiment of the electronic stringed instrument 100 described above, the spectral envelope information is calculated based on cepstrum analysis, but in other embodiments, the spectral envelope information may be calculated based on an all-pole linear predictive analysis method such as LSP (Line Spectrum Pair) analysis.

The functions of FIG. 6 according to the first embodiment of the electronic stringed instrument 100 and the functions of FIG. 11 according to the second embodiment are executed as software processing by the CPU 501 on the sound source output data 513 input from the sound source LSI 504 via the RAM 503 in the hardware configuration of FIG. 5, and the resulting musical tone output data 514 is transferred to the D/A converter 507 via the RAM 503. As another embodiment, a configuration may be adopted in which the sound source LSI 504 executes processing corresponding to the functions of FIG. 6 or FIG. 11 internally, and the resulting musical tone output data 514 is directly output to the D/A converter 507. Alternatively, a configuration may be adopted in which an independent DSP (digital signal processor), for example, executes processing corresponding to the functions of FIG. 6 or FIG. 11 on the sound source output data 513 output by the sound source LSI 504, and the resulting musical tone output data 514 is directly output to the D/A converter 507.

In addition to the control processes of the first and second embodiments of the electronic stringed instrument 100 described above, when the performer changes the fingering position on the fingerboard 108 to a fingering position on a different fret 107 after plucking the string 111, a control process may be executed to issue sound generation control data 512 that changes the pitch of the sound source output data 513 being generated by the sound source LSI 504 corresponding to the string 111 in accordance with the change in fingering position. In this case, for example, in the first embodiment of the electronic stringed instrument 100, a control process is executed to change the center frequency 625 of each of, for example, six band pass filter sections 608 in FIG. 6 in accordance with the change in pitch.

Although the disclosed embodiments and their advantages have been described in detail above, those skilled in the art may make various modifications, additions, and omissions without departing from the scope of the present invention as clearly set forth in the claims.

In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the functions performed in the above-described embodiment may be implemented in appropriate combinations as much as possible. The above-described embodiment includes various steps, and various inventions can be extracted by appropriate combinations of the multiple components disclosed. For example, if the effect can be obtained even if some components are deleted from all the components shown in the embodiment, then the configuration from which these components are deleted can be extracted as an invention.

The following supplementary notes are further disclosed regarding the above-described embodiment.
(Appendix 1)
The tensioned strings and
a plucking detection unit that detects a plucking operation of the strings by a player based on string sound waveform data indicating vibration of the strings;
a plucked-string frequency information calculation unit that calculates plucked-string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the plucked string detection unit detects the plucked string;
a comparison unit for comparing the plucked string frequency information with pre-stored reference frequency information;
a frequency characteristic changing section for changing the frequency characteristic of sound source output data output from a sound source section based on a comparison result of said comparing section, thereby outputting musical sound output data;
An electronic stringed instrument comprising:
(Appendix 2)
2. The electronic stringed instrument according to claim 1, further comprising a string vibration sensor unit that detects vibration of the strings as string sound waveform data.
(Appendix 3)
a pitch designation unit that allows the player to designate a pitch while plucking the strings, and generates pitch information indicating the designated pitch;
a sound generation control data generating unit that generates sound generation control data for controlling generation of the sound source output data based on an intensity of the string sound waveform data at the timing when the plucking detection unit detects the plucking of the string and the pitch information generated by the pitch designation unit, and issues the sound generation control data to the sound source;
3. The electronic stringed instrument according to claim 1 or 2, further comprising:
(Appendix 4)
the pre-stored reference frequency information includes a plurality of sets of reference spectrum information that correspond to a plurality of pitches and indicate frequency spectrum characteristics that serve as a reference for the string sound waveform data corresponding to any plucking operation on the string,
the plucked frequency information calculation unit calculates, as the plucked frequency information, plucked spectrum information indicating a frequency spectrum characteristic of the string sound waveform data due to the pluck after the timing at which the plucked string detection unit detects the plucked operation of the string,
the comparison unit calculates differential spectrum information by subtracting, for each pitch-corresponding frequency which is a fundamental frequency corresponding to the pitch indicated by the pitch information generated by the pitch designation unit or a predetermined number of harmonic frequencies which are a natural number multiple of twice or more of the fundamental frequency, a maximum value or an average value at the pitch-corresponding frequency or its neighboring frequencies of the pre-stored reference spectrum information which corresponds to the string and corresponds to the pitch indicated by the pitch information generated by the pitch designation unit from a maximum value or an average value at the pitch-corresponding frequency or its neighboring frequencies of the plucked string spectrum information;
the frequency characteristic changing unit includes a plurality of band pass filter units, each of which is set as a center frequency for each of the pitch corresponding frequencies, a gain corresponding to a value of the difference spectrum information corresponding to the pitch corresponding frequency, and to which the sound source output data is input; and a mixer unit which mixes outputs of the band pass filter units and outputs the result as the musical sound output data.
4. An electronic stringed instrument as described in claim 3.
(Appendix 5)
5. The electronic stringed instrument according to claim 4, wherein the plucked string spectrum information and the reference spectrum information are calculated by a fast Fourier transform.
(Appendix 6)
the pre-stored reference frequency information includes reference spectrum envelope information indicating a frequency spectrum envelope characteristic serving as a reference for the string sound waveform data corresponding to an arbitrary plucking operation on the string,
the plucked frequency information calculation unit calculates, as the plucked frequency information, plucked spectrum envelope information indicating a frequency spectrum envelope characteristic of the string sound waveform data due to the pluck after the timing at which the plucked string detection unit detects the plucked operation of the string,
the comparison unit calculates difference spectral envelope information by subtracting, at a predetermined frequency interval, a value of the pre-stored reference spectral envelope information corresponding to the string from a value of the plucked string spectral envelope information;
the frequency characteristic changing unit is a convolution filter unit that calculates an impulse response corresponding to the difference spectrum envelope information, convolves the sound source output data with the impulse response, and outputs the musical tone output data.
4. An electronic stringed instrument according to any one of claims 1 to 3.
(Appendix 7)
7. The electronic stringed instrument according to claim 6, wherein the plucked string spectral envelope information and the reference spectral envelope information are calculated by a cepstrum calculation or a line spectrum pair analysis calculation.
(Appendix 8)
The pitch designation unit is
a fingerboard disposed adjacent to the strings and having a plurality of fingering positions defined thereon;
detecting, as string pressing information, information regarding one or more string pressing positions designated by the performer by pressing the strings on the fingerboard;
determining a pitch designated by the performer based on the string pressing information;
generating the pitch information indicative of the determined pitch;
8. An electronic stringed instrument as recited in any one of claims 1 to 7.
(Appendix 9)
The pitch designation unit is
performing a pitch extraction calculation on the string sound waveform data detected by the plucked string detection unit;
determining or correcting a pitch designated by the performer based on the pitch calculated by the pitch extraction calculation;
generating the pitch information indicative of the determined or modified pitch;
9. An electronic stringed instrument according to any one of claims 1 to 8.
(Appendix 10)
The processor that controls the electronic stringed instrument
a plucking detection process for detecting a plucking operation of a string by a player based on string sound waveform data indicating vibration of the string;
a plucked string frequency information calculation process for calculating plucked string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the timing when the plucked string is detected in the plucked string detection process;
a comparison process for comparing the plucked frequency information with pre-stored reference frequency information;
a frequency characteristic changing process for changing the frequency characteristic of the sound source output data output from the sound source unit based on the comparison result of the comparison unit, thereby outputting musical sound output data;
A method for controlling an electronic stringed instrument.
(Appendix 11)
The processor that controls the electronic stringed instrument
a plucking detection process for detecting a plucking operation of a string by a player based on string sound waveform data indicating vibration of the string;
a plucked string frequency information calculation process for calculating plucked string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the timing when the plucked string is detected in the plucked string detection process;
a comparison process for comparing the plucked frequency information with pre-stored reference frequency information;
a frequency characteristic changing process for changing the frequency characteristic of the sound source output data output from the sound source unit based on the comparison result of the comparison unit, thereby outputting musical sound output data;
A program for executing the above.

100 Electronic stringed instrument 101 Body 102 Neck 103 Head 104 Bridge 105 Hexa-divided pickup 106 Control circuit 107 Frets 108 Fingerboard 109 Nut
110 Peg (thread winder)
111 String 201 Sensor board 201
202 Wiring board 301 Coil 401 Capacitor 402 Connector 403 Resonant circuit 404 Sensor 410 Electromagnetic pickup 501 CPU
502 ROM
503 RAM
504 Sound source LSI
505 A/D conversion section 506 Fret sensor interface 507 D/A converter 508 Amplifier 509 Speaker 510 String sound waveform data 511 String pressing information 512 Sound generation control data 513 Sound source output data 514 Musical sound output data 520 System bus 601 Plucked string detection section 602 Pitch determination section 603 Sound generation control data generation section 604 Plucked string spectrum information calculation section 605 Reference spectrum information reading section 606 Difference spectrum information calculation section 607 Band pass filter setting section 608 Band pass filter section 609 Mixer section 620 Intensity 621 Pitch information 622 Plucked string spectrum information 623 Reference spectrum information 624 Difference spectrum information 625 Center frequency 626 Gain 1101 Plucked string spectrum envelope information calculation section 1102 Reference spectrum envelope information reading section 1103 Difference spectrum envelope information calculation section 1104 Difference spectrum envelope information impulse response calculation section 1105 Convolution calculation filter section 1110 Plucked string spectrum envelope information 1111 Reference spectrum envelope information 1112 Difference spectrum envelope information 1113 Difference spectrum envelope information impulse response

Claims (11)

A tensioned string and
a plucking detection unit that detects a plucking operation of the strings by a player based on string sound waveform data indicating vibration of the strings;
a plucked-string frequency information calculation unit that calculates plucked-string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the plucked string detection unit detects the plucked string;
a comparison unit for comparing the plucked string frequency information with pre-stored reference frequency information;
a frequency characteristic changing section for changing the frequency characteristic of sound source output data output from a sound source section based on a comparison result of said comparing section, thereby outputting musical sound output data;
a pitch designation unit that allows the player to designate a pitch while plucking the strings, and generates pitch information indicating the designated pitch;
a sound generation control data generating unit that generates sound generation control data for controlling generation of the sound source output data based on the intensity of the string sound waveform data at the time when the plucking detection unit detects the plucking of the string and the pitch information generated by the pitch designation unit, and issues the sound generation control data to the sound source unit;
An electronic stringed instrument comprising: The electronic stringed instrument of claim 1, further comprising a string vibration sensor unit that detects the vibration of the string as string sound waveform data. the pre-stored reference frequency information includes a plurality of sets of reference spectrum information that correspond to a plurality of pitches and indicate frequency spectrum characteristics that serve as a reference for the string sound waveform data corresponding to any plucking operation on the string,
the plucked frequency information calculation unit calculates, as the plucked frequency information, plucked spectrum information indicating a frequency spectrum characteristic of the string sound waveform data due to the pluck after the timing at which the plucked string detection unit detects the plucked operation of the string,
the comparison unit calculates differential spectrum information by subtracting, for each pitch-corresponding frequency which is a fundamental frequency corresponding to the pitch indicated by the pitch information generated by the pitch designation unit or a predetermined number of harmonic frequencies which are a natural number multiple of twice or more of the fundamental frequency, a maximum value or an average value at the pitch-corresponding frequency or its neighboring frequencies of the pre-stored reference spectrum information which corresponds to the string and corresponds to the pitch indicated by the pitch information generated by the pitch designation unit from a maximum value or an average value at the pitch-corresponding frequency or its neighboring frequencies of the plucked string spectrum information;
the frequency characteristic changing unit includes a plurality of band pass filter units, each of which is set as a center frequency for each of the pitch corresponding frequencies, a gain corresponding to a value of the difference spectrum information corresponding to the pitch corresponding frequency, and to which the sound source output data is input; and a mixer unit which mixes outputs of the band pass filter units and outputs the result as the musical sound output data.
3. An electronic stringed instrument according to claim 1 or 2 . 4. The electronic stringed instrument according to claim 3 , wherein the plucked spectrum information and the reference spectrum information are calculated by a fast Fourier transform. the pre-stored reference frequency information includes reference spectrum envelope information indicating a frequency spectrum envelope characteristic serving as a reference for the string sound waveform data corresponding to an arbitrary plucking operation on the string,
the plucked frequency information calculation unit calculates, as the plucked frequency information, plucked spectrum envelope information indicating a frequency spectrum envelope characteristic of the string sound waveform data due to the pluck after the timing at which the plucked string detection unit detects the plucked operation of the string,
the comparison unit calculates difference spectral envelope information by subtracting, at a predetermined frequency interval, a value of the pre-stored reference spectral envelope information corresponding to the string from a value of the plucked string spectral envelope information;
the frequency characteristic changing unit is a convolution filter unit that calculates an impulse response corresponding to the difference spectrum envelope information, convolves the sound source output data with the impulse response, and outputs the musical tone output data.
3. An electronic stringed instrument according to claim 1 or 2. The tensioned strings and
a plucking detection unit that detects a plucking operation of the strings by a player based on string sound waveform data indicating vibration of the strings;
a plucked-string frequency information calculation unit that calculates plucked-string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the plucked string detection unit detects the plucked string;
a comparison unit for comparing the plucked string frequency information with pre-stored reference frequency information;
a frequency characteristic changing section for changing the frequency characteristic of sound source output data output from a sound source section based on a comparison result of said comparing section, thereby outputting musical sound output data;
the pre-stored reference frequency information includes reference spectrum envelope information indicating a frequency spectrum envelope characteristic serving as a reference for the string sound waveform data corresponding to an arbitrary plucking operation on the string,
the plucked frequency information calculation unit calculates, as the plucked frequency information, plucked spectrum envelope information indicating a frequency spectrum envelope characteristic of the string sound waveform data due to the pluck after the timing at which the plucked string detection unit detects the plucked operation of the string,
the comparison unit calculates difference spectral envelope information by subtracting, at a predetermined frequency interval, a value of the pre-stored reference spectral envelope information corresponding to the string from a value of the plucked string spectral envelope information;
the frequency characteristic changing unit is a convolution filter unit that calculates an impulse response corresponding to the difference spectrum envelope information, convolves the sound source output data with the impulse response, and outputs the musical tone output data.
Electronic string instrument. The electronic stringed instrument according to claim 6, wherein the plucked string spectrum envelope information and the reference spectrum envelope information are calculated by cepstrum calculation or line spectrum pair analysis calculation. A tensioned string and
a plucking detection unit that detects a plucking operation of the strings by a player based on string sound waveform data indicating vibration of the strings;
a plucked-string frequency information calculation unit that calculates plucked-string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the plucked string detection unit detects the plucked string;
a comparison unit for comparing the plucked string frequency information with pre-stored reference frequency information;
a frequency characteristic changing section for changing the frequency characteristic of sound source output data output from a sound source section based on a comparison result of said comparing section, thereby outputting musical sound output data;
a pitch designation unit that allows the player to designate a pitch while plucking the strings, and generates pitch information indicating the designated pitch;
Equipped with
The pitch designation unit is
a fingerboard disposed adjacent to the strings and having a plurality of fingering positions defined thereon;
detecting, as string pressing information, information regarding one or more string pressing positions designated by the performer by pressing the strings on the fingerboard;
determining a pitch designated by the performer based on the string pressing information;
generating the pitch information indicative of the determined pitch;
Electronic string instrument. The pitch designation unit is
performing a pitch extraction calculation on the string sound waveform data detected by the plucked string detection unit;
determining or correcting a pitch designated by the performer based on the pitch calculated by the pitch extraction calculation;
generating the pitch information indicative of the determined or modified pitch;
9. An electronic stringed instrument according to any one of claims 1 to 5 and 8. 1. A method for controlling an electronic stringed instrument, comprising:
a processor controlling the electronic stringed instrument,
a plucking detection process for detecting a plucking operation of a string by a player based on string sound waveform data indicating vibration of the string;
a plucked string frequency information calculation process for calculating plucked string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the timing when the plucked string is detected in the plucked string detection process;
a comparison process for comparing the plucked frequency information with pre-stored reference frequency information;
a frequency characteristic changing process for changing the frequency characteristic of the sound source output data output from the sound source unit based on the comparison result of the comparison process , thereby outputting musical sound output data;
a pitch designation process in which the performer designates a pitch while plucking the strings, and pitch information indicating the designated pitch is generated;
a sound generation control data generation process for generating sound generation control data for controlling generation of the sound source output data, based on an intensity of the string sound waveform data at a timing when a plucked string is detected in the string pluck detection process and the pitch information generated in the pitch designation process, and issuing the sound generation control data to the sound source section;
A method for controlling an electronic stringed instrument that performs the above. The processor that controls the electronic stringed instrument
a plucking detection process for detecting a plucking operation of a string by a player based on string sound waveform data indicating vibration of the string;
a plucked string frequency information calculation process for calculating plucked string frequency information indicating a frequency characteristic of the string sound waveform data due to the pluck after the timing when the plucked string is detected in the plucked string detection process;
a comparison process for comparing the plucked frequency information with pre-stored reference frequency information;
a frequency characteristic changing process for changing the frequency characteristic of the sound source output data output from the sound source unit based on the comparison result of the comparison process , thereby outputting musical sound output data;
a pitch designation process in which the performer designates a pitch while plucking the string, and pitch information indicating the designated pitch is generated;
a sound generation control data generation process for generating sound generation control data for controlling generation of the sound source output data, based on an intensity of the string sound waveform data at a timing when a plucked string is detected in the string pluck detection process and the pitch information generated in the pitch designation process, and issuing the sound generation control data to the sound source section;
A program for executing the above.

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