JP2814699B2 - Music synthesizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical sound synthesizer suitable for use in synthesizing stringed instrument sounds such as piano sounds and plucked string sounds such as guitar sounds.

2. Description of the Related Art A musical sound synthesizer that synthesizes a natural musical instrument sound by operating a model simulating a sounding mechanism of a natural musical instrument is known. As a musical sound synthesizer for a stringed or plucked instrument, a loop circuit including a delay circuit that simulates the propagation delay of vibration in a string and a filter that simulates acoustic loss in the string, and a plucked or struck string in this loop circuit An excitation circuit for inputting an excitation signal corresponding to the excitation vibration at this time is known. Note that this kind of musical sound synthesizer is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-40199.
And Japanese Patent Publication No. 58-58679.

"Problems to be Solved by the Invention" By the way, in the case of a piano, each string is hit with a hammer having a different shape, hardness, and mass. More specifically, the hammer for striking the strings in the bass part has a round shape as shown in FIG. 11 (a), the felt of the striking part is thick and soft, and the mass of the whole hammer is large. As shown in FIG. 11 (b), the hammer that strikes the strings of the section has a tapered shape, the felt of the strike section is thin and hard, and the mass of the entire hammer is small. Therefore, in general, in a piano, a low tone is emitted with a soft tone and a high tone is emitted with a hard tone. However, the above-described conventional tone synthesizer does not simulate a musical instrument having an excitation mechanism having a different structure depending on the pitch, such as a piano, and cannot faithfully reproduce the sound of a natural musical instrument. was there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a tone synthesizer capable of faithfully reproducing the tone of a natural musical instrument having a plurality of excitation mechanisms having different structures.

"Means for Solving the Problems" The present invention relates to a first loop means in which at least a delay means is connected in a closed loop, and the first loop means for generating an excitation signal and
Exciting means for inputting to the loop means, and pitch specifying means for specifying the pitch of a musical tone to be generated, and controlling the delay time of the delay means in accordance with the pitch specified by the pitch specifying means. And a tone synthesizing device for outputting a signal circulating through the first loop means as a tone signal, wherein the excitation means is connected in a closed loop and performs second processing with the first loop means. A signal circulating through the first loop means and an initial signal are input to the second loop means, provided independently of the loop means.
A signal circulating through the second loop means is input to the first loop means as the excitation signal, and the second loop means is controlled according to a pitch designated by the pitch designation means. It is characterized by controlling the amplitude of a circulating signal.

[Operation] According to the above configuration, at least the first loop means in which the delay means are connected in a closed loop is provided independently of the first loop means and connected in a closed loop to perform a predetermined process. A signal circulating through the second loop means to be applied is input as an excitation signal, and the delay time of the delay means is controlled in accordance with the pitch of a musical tone to be generated specified by the pitch specifying means. In addition, a signal circulating through the first loop means and an initial signal are input to the second loop means, and the amplitude of the signal circulating through the second loop means is controlled according to the pitch. Then, a signal circulating in the first loop means is output as a tone signal.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a musical sound synthesizer according to an embodiment of the present invention. 1 is a keyboard for electronic musical instruments, 2
Is a key information generator. Here, when a key pressing operation is performed on the keyboard 1, key code information KC,
A key-on signal KON indicating that a key is pressed and initial touch information IT indicating strength at the time of key pressing are output from the key information generating unit 2, and a key-off signal is output when the key being pressed is released. KOFF is output.

Reference numeral 3 denotes a string-based parameter forming unit, which comprises a microprocessor 31 and a parameter memory 32 realized by a ROM (read only memory), as shown in FIG. The microprocessor 31 receives the key code information KC, the key-on signal KON and the key-off signal KOFF, receives the delay information T _{1 to} T ₆ corresponding to the key code information KC, the filter operation coefficients C _{1 to} C _6, and the multiplication coefficient k ₁ to to generate a k _9. Of these pieces of information, the delay information T _{1 to} T ₆ and the filter operation coefficients C _{1 to} C ₆ are stored in the parameter memory 32 as shown in FIG.
The key code information K is stored when the key-on signal KON is asserted.
Those corresponding to C are read out and outputted by the microprocessor 31. The meanings of these pieces of information T _{1 to} T ₆ , C _{1 to} C ₆ and k _{1 to} k ₉ will be described later.

Reference numeral 4 denotes a hammer system parameter forming unit, the configuration of which is shown in FIG. In the figure, a set-reset flip-flop 43 is set by a key-on signal KON, and a Q output of the flip-flop 43 is taken into a delayed flip-flop 44 by a clock φ generated at a predetermined cycle. The flip-flop 43 is reset by the output. The AND gate 42 is connected to the clock φ and the flip-flop 4
The Q output of 3 is input, and the output of the AND gate 42 is input to the ROM 41 as an output enable signal OE. The ROM 41 stores information indicating a hammer speed corresponding to the initial touch information IT.

According to the hammer parameter forming unit 4, after the key-on signal KON is asserted, the clock φ
The ROM 41 is enabled for a period corresponding to one cycle of, and the hammer speed signal Vh corresponding to the initial touch information IT is output.

Reference numeral 5 denotes a tone generator, the configuration of which is shown in FIG. The tone generator 5 forms a tone of a three-string piano. In FIG. 5, a filter 511, an adder 512,
A delay circuit 513, a multiplier 514, an adder 515, a filter 516, an adder 517, a loop circuit 510 including a delay circuit 518 and a phase inversion circuit 519, and loop circuits 520 and 530 having the same configuration as the loop circuit 510. The reciprocating propagation of vibration in each string is simulated.

Delay circuits 513 and 518, the delay circuit of the variable delay simulates the propagation delay of vibration in the first string, the delay time is controlled by the delay information T ₁ and T ₂ mentioned above. Similarly, delay information T ₃ and T ₄ are supplied to delay circuits 523 and 528 corresponding to the second string, and delay information T ₅ and T ₆ are supplied to delay circuits 533 and 538 corresponding to the third string.
Is supplied. Such a delay circuit with a variable delay time can be realized by, for example, a shift register that delays an input signal and a selector that selects and outputs a delay output of each stage of the shift register according to delay information.

In the case of an actual piano, the tensions of the three strings are not always the same, and a detune effect due to this appears. Therefore, in consideration of the detune effect that can occur in a normal piano, the total delay time of each of the loop circuits 510, 520, and 530 is a value substantially corresponding to the pitch, and is slightly shifted from each other. Delay information T _{1 to} T ₆ are set as described above.

Filters 511 and 516, filters 521 and 526, and filters 531 and 536 simulate acoustic loss at each string. Usually, the higher the frequency, the greater the loss, so these filters are implemented by low-pass filters. Filters 511 and 516, filter 521
And 526, and the filters 531 and 536 are provided with the above-described filter operation coefficients C ₁ and C ₂ , C ₃ and C ₄ , C ₅ and C ₆ , respectively, and based on these, the filter corresponding to the key code information KC An operation is performed.

Phase inversion circuit 519, multiplier 514, phase inversion circuit 529
And multiplier 524, phase inversion circuit 539 and multiplier 534
Is provided to simulate the phase reversal phenomenon that occurs when vibrations are reflected at both ends of each string.During tone generation, the multipliers 514, 524, and 534 include:
The negative multiplication coefficients k ₁ , k ₂ and k ₃ are respectively provided by the chord-based parameter forming unit 3. When the key-off signal KOFF is generated with the key release, the multiplication coefficients k ₁ , k ₂ and k ₃ are switched to small values by the string-based parameter forming unit 3, and the musical tone is rapidly attenuated. .

The output signal of the delay circuit 513 in the loop circuit 510 is multiplied by a multiplier coefficient k ₆ by the multiplier M ₆ , and is introduced into the loop circuit 520 via the adder 525. In addition, the delay circuit 513
The output signal of the multiplier the multiplication coefficient k ₈ by M ₈ is multiplied, is introduced into the loop circuit 530 via the adder 535.
Similarly, the output signal of the delay circuit 523 in the loop circuit 520 is introduced into the loop circuit 510 via the multiplier M ₄ (multiplication coefficient k ₄ ) and the adder 515, and the multiplier M ₉ (multiplication coefficient k 4) ₉ ) and is introduced into the loop circuit 530 via the adder 535. Further, the delay circuit 533 in the loop circuit 530
The output signal, the multiplier M ₅ (multiplication coefficient k ₅₎ and the adder 51
5 and introduced into the loop circuit 510 and the multiplier.
Loop circuit 5 via M ₇ (multiplication coefficient k ₇ ) and adder 525
Introduced within 20. According to such a configuration, signals are exchanged between the loop circuits 510, 520, and 530, and mutual interference of the three strings is simulated. The multiplication coefficients k _{4 to} k ₉ are set according to the degree of mutual interference of the three strings to be realized.

Next, the excitation circuit 550 will be described. This excitation circuit 550
Generates an excitation signal corresponding to the excitation vibration applied to the strings by the hammer. Each output of filter 531 and 536 in the loop circuit 530 is input to the adder 551, the string velocity signal Vs ₁ which corresponds to the speed of the string from the adder 551 is output by the multiplier 552 to the chord velocity signal Vs ₁ Coefficient sadm
Is multiplied. The coefficient sadm will be described later.

Output signal sadm · Vs ₁ of multiplier 552 is integrated by integrating circuit 555 including adder 553 and one-sample period delay circuit 554. Then, a string displacement signal x corresponding to the displacement of the piano string SP from the reference line REF shown in FIG. 9 is output from the integrating circuit 555, and the string displacement signal x is input to one input terminal of the subtractor 556. You. Here, a hammer H output from an integrator 566 described later is connected to the other input terminal of the subtractor 556.
A hammer displacement signal y corresponding to the displacement of M (see FIG. 9) is input. Then, from the subtractor 556, the hammer HM and the string SP
And a relative displacement signal y-x corresponding to the relative displacement with respect to.

Here, if the string SP bites into the hammer HM, y-
x becomes positive, and a repulsion force acts between the string SP and the hammer HM according to the bite amount. On the other hand, when the hammer HM of the string SP is lightly touched or the hammer HM is separated from the string SP, yx is 0 or negative, and the repulsion force is 0.
It is.

The non-linear circuit 557 calculates a repulsion force signal F corresponding to the repulsion force between the string SP and the hammer HM based on the key code information KC and the relative displacement signal y-x, as shown in FIG. It comprises ROMs 557a and 557b and a multiplier 557c. ROM
557a stores a table of a non-linear function such as a quadratic curve shown in FIG. Further, a table of the key scaling coefficient SC is stored in the ROM 557b, and a table corresponding to the key code information KC is read out and given to the multiplier 557c as a multiplication coefficient. Specifically, as shown in FIG. 8, when KC = 21 (corresponding to the lowest tone A1), SC = 1 and KC
= 108 (corresponding to the highest tone C8), the key scaling coefficient SC that changes linearly with the key code information KC is given to the multiplier 557c so that SC = S (S is a predetermined maximum value). . The multiplier 557c multiplies the relative displacement signal yx by the key scaling coefficient SC. Then, the multiplication result is supplied to the ROM 557a as an address, and the ROM 557a
, The signal value of the repulsion signal F is read out.

According to the non-linear circuit 557, when the key code information KC is small, as shown by the symbol B in FIG. 10, the repulsive force signal F that changes slowly with respect to the change in the relative displacement signal yx. Is obtained, and when the key code information KC is large, the relative displacement signal y−
A repulsion signal F that changes steeply with respect to the change in x is obtained.

The repulsion signal F is added to the adders 512 and 517 of the loop circuit 510, the adders 522 and 527 of the loop circuit 520, and the adder 5 of the loop circuit 530.
It is input to 32,537. Normally, the repulsion signal F is multiplied by a coefficient corresponding to the resistance to the change in the speed of the string SP to calculate the change in the speed of the string SP, and 1/2 of the change is calculated by each loop circuit 5.
Although it should be input to 10 to 530, in this embodiment,
By adjusting the above-mentioned multiplication coefficient sadm, the resistance to the above-mentioned speed change is considered.

The repulsion signal F is multiplied by the coefficient fadm by the multiplier 567 to obtain a string speed signal βs corresponding to a speed change given to the string SP by the hammer HM. The string speed signal βs is delayed by one sample period by the delay circuit 568 and input to the integrator 555. This simulates a phenomenon in which the string SP is displaced by being hit by the hammer HM.

The repulsion signal F is input to the multiplier 559. Here, the reciprocal −1 / M of the inertia amount M of the hammer HM corresponding to the key code information KC calculated by the coefficient conversion unit 558 is given to the multiplier 559 as a multiplication coefficient. As a result, the multiplier 5
Hammer acceleration signal α corresponding to the acceleration of hammer HM from 59
Is output. The hammer acceleration signal α is
And a hammer speed signal β corresponding to a speed change of the hammer HM is output from the integrator 562. The hammer speed signal β is multiplied by a predetermined attenuation coefficient through a multiplier 563, and is output from the adder 564 and the delay circuit 565 together with the hammer initial speed signal Vh generated by the hammer parameter forming unit 4. The integrator 566 outputs the above-mentioned hammer displacement signal y.

Each output signal of the delay circuit 513, 523 and 533 in the respective loop circuits are each predetermined multiplier coefficients are multiplied by the multiplier M _11, M ₁₂ and M _13, the output signals of the multipliers by the adder A ₅ The added sound is output as a direct sound signal generated by the vibration of the string SP. This tone signal is given a resonance effect by a filter 6 simulating a sound board of a piano, then converted into an analog signal by a D / A (digital / analog) converter (not shown), and is emitted as a tone from a speaker 7. You.

Hereinafter, the operation of the present embodiment will be described. In the initial state before striking the string, the hammer HM is separated from the string SP, and the relative displacement signal y-x has a negative value in the musical tone forming section 5, so that the repulsive force signal F is 0. I have. The delay circuits 554, 561 and 565 are all reset to zero.

When a key pressing operation of the keyboard 1 is performed, the key information generating unit outputs the key code information KC, the key-on signal KON, and the initial touch information IT of the key. Then, the delay information corresponding to the key code information KC from the string parameter forming unit 3
T _{1 to} T ₆ and filter operation coefficients C _{1 to} C ₆ are output and set in the corresponding parts of the tone generator 5. Further, the hammer system parameter forming unit 4 calculates a hammer initial speed according to the initial touch information IT, and outputs a hammer processing speed signal Vh for a period corresponding to one cycle of the clock φ. Given to.

As a result, the integrated value of the integrator 566, that is, the hammer displacement signal y changes from negative to positive with the passage of time.
During this period, since the string displacement signal x is 0, the relative displacement signal y−x is a negative value (corresponding to a state where the hammer HM and the string SP are separated), and as shown in FIG. F is 0, and the hammer speed signal β is 0. Therefore, the integrator 566
In, only the hammer initial speed signal Vh is integrated.

Then, the relative displacement signal y−x exceeds 0 (the hammer HM
(Corresponding to the state in which the string has collided with the string SP).
A repulsion signal F having a magnitude corresponding to x is output. The repulsion signal F is multiplied by a coefficient −1 / M according to the key code information KC by a multiplier 559 to calculate a hammer acceleration signal α (negative value). is integrated to obtain a hammer speed signal β. Here, since the hammer speed signal β has a negative value, the integrator 566 converts the initial speed signal Vh into the hammer speed signal β.
, The integration is performed, and the temporal change in the increase of the hammer displacement signal y gradually becomes slow. Further, a string speed signal βs corresponding to the hammer repulsion force signal F is generated, and the integrator 55
5, the chord displacement signal x changes.

During this period, the hammer displacement signal y increases in the positive direction (the moving direction of the hammer HM such that the string SP bites), and the relative displacement signal yx increases. As a result, the repulsion signal F increases. Here, repulsive force signal F, if the key code information KC is larger (treble) is a 10 rapidly increases as indicated by arrow F ₁ in the figure, when the key code information KC is smaller (bass) the slowly increased as indicated by the arrow F _2.

As a result of the acceleration signal α being output according to the repulsion signal F generated in this manner, the hammer speed signal β increases in the negative direction (the direction in which the hammer HM moves away from the string SP). When the absolute value of the hammer speed signal β exceeds the initial speed signal Vh and the direction of the speed of the hammer HM is reversed in a direction away from the string SP, the hammer displacement signal y changes in a negative direction. Then, the relative displacement signal y−x gradually decreases, and accordingly, the repulsion signal F decreases. Again, repulsive force signal F, as shown in FIG. 10, when the treble is rapidly attenuated as indicated by the arrow F _3, when the bass arrow F ₄
Slowly decays as indicated by. Then, the relative displacement signal y−x <0, that is, the hammer HM is separated from the string SP, and the string striking operation ends.

In this manner, the repulsion signal F at the time of the string striking operation is calculated, and this repulsion signal F is input to the loop circuits 510, 520 and 530 as the contribution of the speed change given to the string SP by the hammer HM, that is, the excitation signal. You. And the loop circuit
At each of 510, 520 and 530, the input excitation signal circulates. Also, the signal circulating in the loop circuit 510 is
Is introduced into the loop circuit 530 via a multiplier M ₈ while being introduced into the loop circuit 520 via a multiplier M _6, likewise, the introduction of the signal from the loop circuit 520 to the loop circuit 510 and 530, and the loop circuit Loop circuits 510 and 520 from 530
Signal is introduced to simulate the mutual interference of the three strings.

Then, after each output signal of the loop circuits 510, 520 and 530 via respective multipliers M _11, M ₁₂ and M _13, the musical tone signals are summed by summer A ₅ is formed, for this musical tone signal, the filter 6 As a result, a resonance effect is provided, and the sound is generated as a musical tone from the speaker 7.

In the above-described embodiment, the case where the musical sound synthesizer is realized by a digital circuit has been described. However, it is of course possible to realize the musical sound synthesizer by an analog circuit, and the same effects as those realized by a digital circuit can be obtained. As a loop circuit including a delay circuit, the above-mentioned Japanese Patent Application Laid-Open No.
It is also possible to use the waveguide disclosed in Japanese Patent Publication No. 9-No. In the above embodiment, a non-linear table or the like for simulating the amount of inertia M of the hammer and the elastic characteristic of the felt is selected according to the key code information KC. Instead of setting parameters, the player may be able to arbitrarily set various parameters in order to freely create sounds. Further, a plurality of sets of hammer parameters may be easily set for one key code, and may be switched and used according to operation of a tone switch or the like.
Also, instead of using a non-linear table to realize the felt elasticity, the felt may be calculated. Further, in the above embodiment, the key scaling coefficient SC is linearly changed with respect to the key code information KC. The key scaling coefficient SC corresponding to each key code information KC may be set. In addition, in order to freely create a sound, an arbitrary key scaling coefficient SC may be set. Also, each delay circuit used in the tone generator is
It may be a RAM (random access memory) or an analog delay circuit. In addition, the present invention can be realized not only by hardware but also by software.

[Effects of the Invention] As described above, according to the present invention, the excitation means is provided with the second loop means connected in a closed loop and performing a predetermined process independently of the first loop means. A signal circulating through the first loop means and a signal circulating through the second loop means are supplied as an excitation signal to the second loop means, while a signal circulating through the first loop means having at least delay means connected in a closed loop is input to the second loop means. Since the input is made to the first loop means, it is possible to faithfully imitate a physical phenomenon when a hammer of a natural musical instrument strikes a string,
The effect is that the musical sounds of the piano can be faithfully synthesized. Further, since the excitation means controls the amplitude of the signal circulating through the second loop means in accordance with the pitch specified by the treble specifying means, the hammer corresponding to the pitch in the piano of the natural musical instrument. Can faithfully imitate the difference in the structure / size of the piano, and the effect that the tone of the piano can be synthesized more faithfully is also obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a musical sound synthesizer according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a string-based parameter forming section 3 in the embodiment, and FIG. The figure showing the storage contents of the parameter memory 32,
FIG. 4 shows a hammer system parameter forming section 4 in the embodiment.
FIG. 5 is a block diagram showing a configuration of the tone generator 5 in the embodiment, FIG. 6 is a block diagram showing a configuration of the nonlinear circuit 557 in the embodiment, FIG.
FIG. 8 is a diagram showing a non-linear table in the embodiment, FIG. 8 is a diagram showing a key scaling coefficient SC in the embodiment,
FIG. 9 shows a hammer HM and a string simulated by the embodiment.
FIG. 10 is a diagram showing the state of the SP at the time of string striking, FIG. 10 is a diagram illustrating the change of the repulsion force signal F with respect to the relative displacement signal y-x in the embodiment, and FIG. 11 is a diagram generally showing the shape of a piano hammer. FIG. 1 ... keyboard, 3 ... string system parameter forming unit, 4 ... hammer system parameter forming unit, 5 ... musical tone forming unit, 510, 520, 53
0: loop circuit, 550: excitation circuit, 553: adder, 5
54 delay circuit, 555 integration circuit, 556 adder, 55
9 ...... multipliers, F ...... repulsion signal, Vh ...... hammer initial velocity signal, Vs ₁ ...... string velocity signal.

Continuation of the front page (56) References JP-A-53-88715 (JP, A) "THE VEN ICE 1982 INTERNAL AL COMPUTER MUSIC COMFERENCE" held from September 27 to October 1, 1982 in Venice, Italy. Minutes, pages 308-339, "Synthesis of Bowed Strings", Julius. O. Smith (58) Field surveyed (Int. Cl. ⁶ , DB name) G10H 7/00-7/12

Claims (1)

(57) [Claims] 1. A first loop means in which at least delay means are connected in a closed loop, an excitation means for generating an excitation signal and inputting the signal to the first loop means, and designating a pitch of a musical tone to be generated. A tone specifying means for controlling a delay time of the delay means in accordance with a pitch specified by the pitch specifying means, and outputting a signal circulating through the first loop means as a tone signal. In the synthesizing device, the excitation means is provided with a second loop means connected in a closed loop and performing a predetermined process independently of the first loop means, and a signal circulating through the first loop means is provided. And inputting an initial signal to the second loop means, and inputting a signal circulating through the second loop means to the first loop means as the excitation signal,
A tone synthesizer for controlling the amplitude of a signal circulating in the second loop means according to a pitch designated by the pitch designation means.