JP2679311B2 - Music synthesizer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a musical tone synthesizing apparatus suitable for synthesizing the sound of a stringed instrument such as a rubbed string instrument, a plucked string instrument, and a stringed instrument.

2. Description of the Related Art There is known an apparatus that operates a model obtained by simulating a sounding mechanism of a natural musical instrument and thereby synthesizes a musical sound of the natural musical instrument. As a musical sound synthesizer for a stringed instrument sound or the like, there is known a configuration in which a low-pass filter simulating acoustic loss of a string and a delay circuit simulating propagation delay of vibration in the string are connected in a closed loop. . In such a configuration, when an excitation signal such as an impulse is introduced into the closed loop, signal circulation occurs in the closed loop. In this case, the band of the signal is limited when the signal makes one round in the closed loop and passes through the low-pass filter at a time equal to the cycle of one round trip of the vibration of the string. The signal circulating in this closed loop is extracted and output as a musical sound. According to such a device, by adjusting the delay time of the delay circuit, the characteristics of the low-pass filter, etc., the sound of a plucked instrument such as a guitar,
It is possible to synthesize a musical tone that is close to a natural stringed instrument sound, such as a percussion instrument sound of a piano. A musical tone synthesizer for a plucked musical instrument sound, such as a violin, is realized by connecting an exciting circuit for calculating vibrations excited by a bow to a string to a closed loop circuit similar to that described above. It should be noted that this type of technology is disclosed in, for example, Japanese Patent Laid-Open No. 63-40199 or Japanese Patent Publication No.
It is disclosed in Japanese Patent Publication No. 8-58679.

[Problems to be Solved by the Invention] In the case of a violin, when a bow rubs a string, vibration is excited in the string and a musical sound is generated. But,
The violin bow is configured by bundling a large number of hairs of a horse's tail, and excitation vibrations are introduced into the strings through each rubbing string position where a large number of hairs come into contact with the strings. However, in the above-described conventional tone synthesizer, the excitation signal is input to a specific point in the closed loop circuit, so that the tone of a stringed instrument such as a violin in which excited vibrations are introduced from many stringed positions is faithfully reproduced. There was a problem that it could not be synthesized. This is not limited to a stringed instrument, and even in the case of a plucked string instrument such as a guitar, for example, a part of a string having a certain length is played by a pick to generate a musical sound. Therefore, the conventional musical tone synthesizer having only one introduction point of the excitation signal has a problem that a musical tone rich in reality cannot be obtained.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a musical sound synthesizer that faithfully simulates a mechanism of introducing an exciting vibration to a string in a stringed instrument.

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim 1 includes at least a delay means, and a closed loop means which is connected in a loop, and an excitation signal is generated to generate the closed loop means. And an exciting means for inputting to at least four different points, and the delay means is provided between each of the at least four points.

The invention according to claim 2 includes at least two different excitation signals based on closed loop means including at least delay means and connected in a loop, and predetermined performance information and a signal circulating through the closed loop means. Excitation signal generating means for generating the at least two excitation signals are respectively input to different points of the closed loop means.

The invention according to claim 3 is the same as claim 1 or claim 2.
In the musical tone synthesizing apparatus described above, a control means for controlling the delay of the entire closed loop means according to the pitch of the musical sound to be generated and for changing and controlling a part of the delay time of the delay means based on predetermined performance information. It is characterized by including.

[Operation] According to the above configuration, at least four points to which the excitation signal is input are set so as to sandwich the delay element provided in the closed loop means, and the input excitation signal is different from the one to which the excitation signal is input. There will always be a delay before reaching the point. Then, the introduced excitation signal circulates in the closed loop circuit while being delayed.

Further, the excitation signal generated by the excitation signal generating means on the basis of the predetermined performance information and the signal circulating in the closed loop means is inputted to two different points in the closed loop and circulates in the closed loop.

Further, a part of the delay time of the delay means is changed based on predetermined performance information, and the delay of the entire closed loop means is controlled according to the pitch of the musical sound to be generated, and the delay amount of the excitation signal is controlled. It circulates in a closed loop means. In this way, the sounding mechanism of a musical instrument such as a violin in which excited vibrations are applied to the strings through many driving positions is faithfully simulated.

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. This musical sound synthesizer is for synthesizing a violin sound, a closed loop circuit 100 simulating a string of a violin, an excitation circuit 101, 102 for generating an excitation signal corresponding to an excitation vibration given by a bow to the string,
And a control unit 103 that controls the entire apparatus.

Here, before the detailed description of each of the above-mentioned components, the mechanism when the excitation vibration is introduced into the string of the violin will be described. In FIG. 2, S indicates a violin string and L indicates a bow. Also, fixed ends for fixing both ends of the string S
T ₁ and T ₂ correspond to the violin nut and bridge, respectively. When the bow L is pressed against the string S and played (arrow U), the bow L
During the period in which the static friction force between the string S and the string S acts, the string S moves with the movement of the bow L, the displacement of the string S increases, and the impulse determined by the elastic force of the string S produces the static friction force. When it exceeds, the string S slides with respect to the bow L and tries to return to the original position. In this way, the bow L excites vibration on the string S. In reality, since the bow L is composed of a bundle of many hairs, the vibration is excited at each rubbing string position where the string S and one hair contact each other. In Figure 2
A ₁ indicates the rubbed string position from the fixed end T ₁ of the string S, and A ₂ shows the rubbed string position closest to the fixed end T ₂ .

The vibration excited in the string S at each rubbing string position is branched into two and propagates as a vibration wave Wa to the fixed end T ₁ side and also to the fixed end T ₂ side as a vibration wave Wb. And the vibration wave Wa
Is reflected and phase-inverted at the fixed end T ₁ , the reflected wave propagates to the fixed end T ₂ side, and the vibration wave Wb is phase-inverted and reflected at the fixed end T ₂ , and the reflected wave is Propagate to the T ₁ side. Then, the string S vibrates according to the standing wave Ws whose nodes are the fixed ends T ₁ and T ₂ obtained by adding the vibration waves Wa and Wb.

The loop circuit 100 in FIG. 1 simulates the vibration propagation mechanism in the string S as described above, and includes a delay circuit 1, an adder 2, a low pass filter 3, a phase inversion circuit 4, a delay circuit 5, and an addition circuit. 6, delay circuit 7, adder 8, low-pass filter 9, phase inversion circuit 10,
It is composed of a delay circuit 11 and an adder 12.

Each of the delay circuits 1, 5, 7 and 11 has a configuration capable of adjusting the delay time, and the delay time is controlled by the control unit 103. A delay circuit of this type can be realized by, for example, a shift register and a selector that selects each delay output of the shift register. The delay time of each delay circuit is set by the control unit 103 as described below. First, the delay time τa of the delay circuit 11
Is set according to the time required for the vibration wave Wa to reciprocate from the rubbing position A ₁ to the fixed end T ₁ of the string S. Further, the delay time τb of the delay circuit 5 is set in accordance with the time required for the vibration wave Wb to make a round trip in the portion of the string S from the rubbed string position A ₂ to the fixed end T ₂ . Further, the delay time τ ₁ of the delay circuits 1 and 7 is set according to the propagation delay time of the vibration of the part of the string S from the rubbing position A ₁ to the rubbing position A ₂ .

The phase inversion circuits 4 and 10 are provided for simulating the phenomenon that the oscillation waves Wa and Wb undergo phase inversion at the fixed ends T ₁ and T ₂ . Further, the low-pass filters 3 and 9 are inserted in order to simulate the frequency characteristic of vibration attenuation in the string S. By inserting these, in each frequency component of the vibration generated in the string S, a phenomenon in which the higher the higher harmonic component is, the more rapidly it is attenuated is faithfully simulated.

The excitation circuits 101 and 102 each generate an excitation signal corresponding to the excitation vibration applied to the string S by the bow L.

The excitation circuit 101 includes an adder 21, a divider 22, a nonlinear function generation circuit 23, and multipliers 24 and 25. In the adder 21,
Output signals Va ₁ of the delay circuit 11, a signal indicating the moving speed of the output signals Va ₂ and bow L of the delay circuit 7 VA (hereinafter, bow speed signal VA
Is called) is added. Where the signals Va ₁ and Va ₂ are
Respectively so corresponds to the velocity component of the vibration wave Wa and Wb in bowed string position A ₁ of the string S, these added values, bowed string position A ₁
Corresponds to the speed of the string S at. Then, a value obtained by further adding the bow velocity signal VA to the added value, that is, the bow L and the bow S when it is assumed that the bow S does not follow the bow L at all.
A signal VAS (hereinafter, referred to as a speed difference signal VAS) corresponding to a provisional equivalent speed is output from the adder 21. Here, the bow speed signal VA is output from the control unit 103. The bow velocity signal VA is stored in a memory (not shown) of the control unit 103, in which data indicating temporal changes in the bow velocity obtained by observing the movement of the bow L in an actual violin performance is stored to generate a musical tone. It may be read at any time, or may be input by a special operator.

The circuit including the divider 22, the nonlinear function generating circuit 23, and the multiplier 24 simulates the followability of the string S with respect to the movement of the bow L. In the divider 22 and the multiplier 24,
Signals F ₁ to arch L at bowed string position A ₁ corresponds to the pressure to press the string S (hereinafter, referred to as the bow pressure signal F ₁₎ are each provided as a division factor and multiplication factor. On the other hand, the bow pressure signal F ₂ corresponding to the rubbing position A ₂ is applied to the corresponding portion of the excitation circuit 102. These bow pressure signals F ₁
Also, F ₂ and F ₂ are supplied from the control unit 103 similarly to the above-mentioned bow speed signal VA.

Here, in the actual violin performance, the angle of the bow L with respect to the string S changes with time, so the rubbed string positions A ₁ and A ₂
The bow pressure at also changes with time. In the present embodiment, in consideration of this, the temporal change of the total pressure of the bow L and the chord S of the bow L are taken.
Based on the temporal change of the angle with respect to, the data showing the temporal change of the bow pressure at the rubbing positions A ₁ and A ₂ is created and recorded in the memory of the control unit 103, and sequentially read when the musical tone is generated and the bow pressure signal is generated. Output as F ₁ and F ₂ . The bow pressure signals F ₁ and F ₂ may be controlled in real time by operating a special operator.

As shown in FIG. 3, the nonlinear function generating circuit 23 is
1, 42, a multiplier 43 and an adder 44. RO
The output of the divider 22 shown in FIG. 1 is applied to both M41 and 42 as an input X. The ROM 41 stores a table of the non-linear function A whose contents are shown in FIG. As shown in the figure, when the input X is in the range of -Xm to Xm, the output Y of the ROM 41 is -X, and in other cases, the output Y of the ROM 41 is 0. The ROM 42 stores the table of the non-linear function B shown in FIG. As shown in the figure, input X
Is in the range of -Xm to Xm, the output Y of the ROM 41 is 0.
When the input X exceeds Xm, the output Y becomes a negative value,
Thereafter, Y gradually approaches 0 as the input X increases in the positive direction. Also, if the input X falls below -Xm, the output Y
Becomes a positive value, and Y gradually approaches 0 as the input X increases in the negative direction. Then, the output of the ROM 42 is multiplied by the bow pressure signal F ₁ by the multiplier 43, and the multiplication result and the output of the ROM 41 are added by the adder 44.
Therefore, the input / output characteristics of the entire nonlinear function generating circuit 23 are as shown in FIG. As shown in the figure, the non-linear function generating circuit 23 obtains the output Y (= -X) according to the non-linear function A in the section where the input X is -Xm to Xm, and the section where the input X is smaller than -Xm. In the section where the input X is larger than Xm, the output Y is obtained by expanding the non-linear function B in the Y-axis direction according to the value of the bow pressure signal F ₁ .

Further, the divider 22 is provided in the previous stage of the nonlinear function generating circuit 23.
However, since the multiplier 24 is inserted in the subsequent stage, as shown in FIG. 7, the input / output characteristic obtained by expanding the input / output characteristic of FIG. 6 in the X direction and the Y direction according to the bow pressure signal F ₁ is obtained. , Divider 2
2. Obtained as the input / output characteristics of the nonlinear function generating circuit 23 and the multiplier 24 as a whole.

When the absolute value of the speed difference signal VAS supplied from the adder 21 is small, the output signal is determined according to the linear region S ₀ in the input / output characteristic of FIG. 7, and the excitation signal VAM with VAM ₁ = −VAS
₁ is output from the multiplier 24. Then, the excitation signal VAM ₁ is multiplied by 1/2 by the multiplier 25, and the multiplication result (1/2) VAM ₁
Are input to the adders 12 and 8. As a result, the adder 12
Output Va ₃ is Va ₃ = Va ₁ + (1/2) VAM ₁ = Va _1- (1/2) VAS = Va _1- (1/2) (VA + VS) (1), and the adder the output Va ₄ of _{8, Va 4 = Va 2 + (} 1/2) VAM 1 = Va 2 - a (1/2) (VA + VS) ...... (2) - (1/2) VAS = Va 2. However, in the above formulas (1) and (2),
VS is Va ₁ + Va ₂ , which corresponds to the speed of the string S when the effect of rubbing is not considered. The signal thus obtained
Va ₃ and Va ₄ are input to the delay circuit 1 and the low-pass filter 9 as signals indicating the vibration waves Wa and Wb at the rubbing position A ₁ in which the effect of the rubbing is considered. Here, the sum of the signals Va ₃ and Va ₄ corresponds to the velocity VSL of the string S in consideration of the effect of the rubbing. In this _{case, VSL = Va 3 + Va 4} = Va 1 + Va 2 - the (VA + VS) = -VA ...... (3). That is, the string S moves at the same speed as the bow L.
In this embodiment, the forward direction when the bow L moves and the forward direction when the string S moves are defined as the opposite directions.
In this way, the static frictional force acts between the bow L and the string S, and the operation in the case where the string S is displaced following the bow L completely is simulated.

On the other hand, when the absolute value of the speed difference signal VAS becomes large, the operating point of the excitation circuit 101 changes from the linear region S ₀ to the curved region P ₁ , P ₂ , P ₃ , ... Or Q ₁ , Q ₂ , Q in FIG. ₃ , and the values in these curved regions are output as the excitation signal VAM ₁ . Where the curved regions P ₁ , P ₂ , P ₃ , ... and Q ₁ , Q ₂ ,
Q ₃ , ... Correspond to the state in which the string S is displaced while sliding with respect to the bow L.

Here, as shown in FIG. 7, the transition point from the straight line region S ₀ to the curved region becomes farther from the origin as the bow pressure signal F ₁ becomes larger. By doing so, a phenomenon in which the greater the pressing force of the bow L is, the better the followability of the string S to the bow L is simulated. In addition, in the curve area that is the transition destination, as the bow pressure signal F ₁ increases, P ₁ (Q ₁ ) → P
₂ (Q ₂ ) → P ₃ (Q ₃ ) → It changes. By doing so, even when the string S slides on the bow L, a phenomenon in which the greater the pressing force of the bow L is, the better the followability of the string S to the bow L is simulated.

Then, the output signal VAM ₁ of the multiplier 24 is divided into two by the multiplier 25 and is given to the adders 12 and 8. in this case,
The signals Va ₃ and Va ₄ change only slightly from the signals Va ₁ and Va ₂ because the values in the curved region are used as the excitation signal VAM ₁ . In this way, the operation when dynamic friction acts between the bow L and the string S is simulated.

The excitation circuit 102 is also realized by the same configuration as the excitation circuit 101, and the bow velocity signal VA and the bow pressure signal F ₂ supplied from the control unit 103, the output signal Vb ₁ of the delay circuit ₁ and the delay circuit 5 are provided.
Of the excitation signal VAM ₂ is generated based on the output signal Vb _{2 of the above-mentioned} signal and half of the excitation signal VAM ₂ is supplied to adders 2 and 6.

Hereinafter, the operation of the tone synthesizer will be described. Prior to the generation of the musical sound, the control unit 103 sets the delay times of the delay circuits 1, 5, 7, and 11. In this case, the delay time of each delay circuit is set such that the time required for the signal to make one round in the closed loop circuit 100 is the reciprocal of the primary resonance frequency of the generated musical sound. Then, the control unit 103 outputs the bow velocity signal VA and the bow pressure signals F ₁ and F ₂ , the bow velocity signal VA and the bow pressure signal F ₁ are supplied to the excitation circuit 101, and the bow velocity signal VA and the bow pressure signal F ₂ is supplied to the excitation circuit 102. Then, as described above, the excitation signal VAM ₁ is generated by the excitation circuit 101, 1/2 of which is input to the closed loop circuit 100 via the adders 12 and 8, and the excitation signal VAM ₂ is generated by the excitation circuit 102. And 1/2 of that is input to the closed loop circuit 100 via the adders 2 and 6.

Then, the signals output from the excitation circuits 101 and 102 and introduced into the closed loop circuit 100 circulate in the loop,
It is re-input to the excitation circuits 101 and 102. This operation is the second
In the figure, the vibration applied to the string S by the bow L propagates from the rubbing position to the left and right, is reflected by each fixed end, and returns to the rubbing position again. Then, thereafter, similarly, the excitation circuits VAM ₁ and VAM ₂ are calculated by the excitation circuits 101 and 102 and input to the closed loop circuit 100, which is repeated. Then, the signal circulating in the closed loop circuit 100 is taken out as a musical tone signal and sent to the sound system to produce a synthesized sound of the violin sound.

In the above-described embodiment, the case where _two exciting circuits are provided for the rubbing string positions A ₁ and A ₂ has been described. However, the exciting circuit is provided corresponding to each rubbing string position existing between A _{1 and} A _2. By adding a circuit, more strict tone synthesis can be performed. vice versa,
As in the above embodiment, instead of preparing both the excitation circuits 101 and 102, only one excitation circuit is provided, and the output of the excitation circuit is the rubbing positions A ₁ and A in the closed loop circuit 100.
_Even if input is made at each position corresponding to ₂ , it is possible to obtain a synthetic sound that is close to the actual violin sound to some extent. Further, in the above embodiment, the delay circuits 1 and 7 having the same delay time are provided corresponding to the propagation delay between the rubbing positions A _{1 and} A ₂ , but the delay times of both may be unbalanced.
Also, one delay circuit may be omitted. Also, a keyboard is connected to the tone synthesizer according to the above-mentioned embodiment, and the delay circuit 1,
Parameters such as delay time distributions 5, 7, and 11, bow pressure signals F ₁ and F ₂ , bow speed signal VA, etc. may be changed according to initial touch, aftertouch, etc. when the keyboard is hit. . For example, when the touch is strong, the delay time τa of the delay circuit 11 is decreased, the delay time τb of the delay circuit 5 is increased, the delay time τ ₁ of the delay circuits 1 and 7 is increased, and the bow pressure signal F is further increased. Increase ₁ and F ₂ . In this way, a tone of strong expression is realized.
When the touch is weak, the delay time τa of the delay circuit 11
And the delay time τb of the delay time 5 are made close to each other, and the delay time τ ₁ of the delay circuits 1 and 7 is made smaller.
Make F ₁ and F ₂ small. In this way, a tone with a weak expression is realized. The delay time distribution of each delay circuit, the bow pressure signals F ₁ and F ₂ , and the bow speed signal VA may be changed in accordance with the key code of the generated musical sound.
Further, in the above-mentioned embodiment, the case where the present invention is applied to the musical tone synthesizing device for a stringed instrument is explained, but the same effect can be obtained even when the present invention is applied to a plucked string instrument and a stringed instrument.

[Advantages of the Invention] As described above, according to the present invention, closed loop means including at least delay means and connected in a loop, and an excitation signal are generated and input to at least four different points of the closed loop means. Since the delay means is provided between each of the at least four points, it is possible to faithfully synthesize an instrument into which the exciting vibration is introduced through a wide range of the sounding body. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a musical sound synthesizing apparatus according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a mechanism of introducing excitation vibration to a string of a violin, and FIG. 3 is a nonlinear view of the embodiment shown in FIG. A block diagram showing the configuration of the function generating circuit 23, and FIGS. 4 to 7 are diagrams for explaining the non-linear function used in the same embodiment. 100 ... Closed loop circuit, 101,102 ... Excitation circuit, 103 ...
Control unit.

Claims (3)

(57) [Claims] 1. A closed loop means comprising at least a delay means and connected in a loop, and an excitation means for generating an excitation signal and inputting it to at least four different points of the closed loop means, the delay means A tone synthesizer provided between each of the at least four points. 2. An excitation signal generator for generating at least two different excitation signals based on closed loop means including at least delay means and connected in a loop, and predetermined performance information and a signal circulating through the closed loop means. Means for inputting the at least two excitation signals to different points of the closed loop means, respectively. 3. A control means for controlling the delay of the entire closed loop means according to the pitch of a musical sound to be generated, and for changing and controlling a part of the delay time of the delay means based on predetermined performance information. The musical sound synthesizer according to claim 1 or 2, wherein