JPH03163599A - Musical sound synthesizer circuit - Google Patents

Abstract

PURPOSE:To faithfully synthesize musical sound by computing the excitation signals corresponding to the excited oscillations applied to a sound producing body to nodes. CONSTITUTION:This device has a closed loop circuit 100 which simulates the string of a violin, excitation circuits 101, 102 for generating the excitation signals corresponding to the excited oscillations that a bow applies, and a control section 103 which controls the entire part of the device. The computation of the excitation signals and the introduction of the excitation signals to the closed loop circuit 100 are executed at the respective nodes selected to sandwich delay circuits 1, 5, 7, 11 in the closed loop circuit 100. The circulation of the introduced excitation signals is executed in the closed loop circuit 100. The sound production mechanism of a musical instrument, such as violin, by which the excited oscillations are applied to the strings via many driving positions is faithfully simulated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a musical tone synthesis device suitable for use in synthesizing sounds of string instruments such as bowed string instruments, plucked string instruments, and percussion string instruments.

"Prior Art" A device is known that operates a model obtained by simulating the sound production mechanism of a natural musical instrument, thereby synthesizing the musical tones of the natural musical instrument. A known musical sound synthesis device for stringed instrument sounds is one in which a low-pass filter that simulates the acoustic loss of the strings and a delay circuit that simulates the propagation delay of vibrations in the strings are connected in a closed loop. . In such a configuration, when an excitation signal such as an impulse is introduced into the closed loop, circulation of the signal occurs within the closed loop. In this case, the signal makes one round in the closed loop in a time equal to the period of one round trip of vibration on the string, and the signal is band-limited when passing through the low-pass filter.

The signal circulating in this closed loop is extracted and output as a musical tone. According to such a device, by adjusting the delay time of the delay circuit, the characteristics of the low-pass filter, etc., it is possible to synthesize a musical sound that is somewhat similar to the sound of a natural stringed instrument, such as the sound of a plucked string instrument such as a guitar, or the sound of a percussion instrument such as a piano. be able to. In addition, a musical tone synthesis device for the sound of a stringed instrument such as a violin,
This is realized by connecting an excitation circuit that calculates the vibrations excited in the string by the bow to a closed loop circuit similar to the one described above. Note that this type of technology is disclosed in, for example, Japanese Patent Application Laid-open No. 1983-
It is disclosed in Japanese Patent Publication No. 40199 or Japanese Patent Publication No. 58-58679.

``Problems to be Solved by the Invention'' In the case of a violin, the friction of the bow against the strings excites vibrations in the strings, producing musical sounds. However, a violin bow is constructed by bundling together a large number of horse tail hairs, and excitation vibrations are introduced into the string through each string rubbing position where a large number of hairs come into contact with the string. however,
The conventional musical tone synthesizer described above inputs an excitation signal to a specific point in a closed loop circuit.
There has been a problem in that it is not possible to faithfully synthesize the musical sounds of a bowed string instrument such as a violin, in which excitation vibrations are introduced from many bowed string positions. This is not limited to stringed instruments; for example, it also applies to plucked stringed instruments such as guitars.
The string is struck not at a single point, but over a certain length with the pick, producing a musical sound. Therefore, a conventional musical tone synthesizer having only one introduction point for an excitation signal has a problem in that realistic musical tones cannot be obtained.

The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a musical tone synthesis device that faithfully simulates the mechanism of introducing excited vibrations into the strings of a stringed instrument.

"Means for Solving the Problems" In order to solve the above problems, the present invention comprises a sounding body and a sounding operator that excites a part of the sounding body and generates vibrations that propagate back and forth through the sounding body. In a musical tone synthesizer for synthesizing musical tones of natural music 4, a plurality of delay elements are cascaded in a loop shape, and vibrations propagate back and forth through the sounding body over the delay time required for a signal to go around the loop. a closed loop circuit whose period is equal to that of the sound generator; "Action" characterized by comprising excitation means that calculates a corresponding excitation signal and supplies the excitation signal to the node. According to the above configuration, each node is selected so as to sandwich a delay element in the closed loop circuit. In , the calculation of the excitation signal and the introduction of the excitation signal into the closed-loop circuit take place. The introduced excitation signal then circulates in the closed loop circuit. In this way, the sounding mechanism of a musical instrument such as a violin, in which the strings are subjected to excitation vibrations through a number of drive positions, is faithfully simulated.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a musical tone synthesizer according to an embodiment of the present invention. This musical tone synthesis device synthesizes violin sounds, and includes a closed loop circuit 100 that simulates violin strings, and an excitation circuit 101 that generates an excitation signal corresponding to the excitation vibration that a bow gives to the strings.
02. Control unit that controls the entire lifting device! Consists of 03.

Here, before providing a detailed explanation of each of the above-mentioned components, a mechanism when excited vibrations are introduced into a violin string will be explained. In Figure 2, S is a violin string,
shi indicates a bow. Also, a fixed end T1 that fixes both ends of the string S
and 'r, correspond to the nut and bridge of the violin, respectively. When the bow L is pressed against the string S and played (arrow U), during the period when the static friction force between the bow L and the string S is exerted, the string S moves as the bow L moves, and the displacement of the string S is When the force increases and the impulse determined by the elastic force of the string S exceeds the static IE friction force, the string S slides relative to the bow L and attempts to return to its original position. In this way, vibrations are excited in the string S by the bow (2). In reality, since the bow L is composed of a large number of bundles of hairs, the vibration is excited at each string position where each hair is in contact with the string S. A in FIG. A indicates the position where the string is rubbed at the most fixed end T on the string S, and A indicates the position where the string is rubbed at the most fixed end T.

The vibration excited in the string S at each string rubbing position is branched into two, and is transmitted as a vibration wave Wa toward the fixed end T1 side, and as a vibration wave Wb toward the fixed end T. Then, the vibration wave Wa is transmitted to the fixed end T. The reflected wave propagates toward the fixed end 'r, and becomes a vibration wave wb.
is phase-inverted and reflected at the fixed end Tt, and the reflected wave propagates toward the fixed end T1. The string S vibrates according to a standing wave Ws whose nodes are the fixed ends T+ and 'r, which are obtained by adding the vibration waves Wa and wb.

Loop circuit in Figure 1! 00 simulates the vibration propagation mechanism in the string S as described above, and includes a delay circuit I, an adder 2, a J-pass filter 3, a phase inversion circuit 4, a delay circuit 5, an adder 6, Delay circuit 7, adder 8, low pass filter 9, phase inversion circuit 10
, delay circuit 11 and adder 412.

Delay circuits 1, 5, 7 and! (2) Each of them has a configuration in which the delay time can be adjusted, and the delay time is controlled by the control unit 103. Note that this type of delay circuit can be realized by, for example, a shift register and a selector that selects each delayed 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 l1 is set in accordance with the time required for the vibration wave Wa to reciprocate in the portion of the string S from the string rubbing position A1 to the fixed end 'r1. Moreover, the delay time τb of the delay circuit 5 is
U' is set in accordance with the time that the vibration wave wb travels back and forth from the string rubbing position A to the fixed end T on the string S. Further, the delay time τ1 of the delay circuits I and 7 is set in accordance with the propagation delay time of vibration in the portion of the string S from the string rubbing position A+ to the string rubbing position A.

The phase inversion circuit 4 and lO are connected to the fixed end T. This is provided to simulate the phenomenon in which the phases of vibration waves Wa and wb are reversed at and T. Furthermore, the low-pass filters 3 and 9 are inserted to simulate the frequency characteristics of vibration damping in the string S. By mediating these, in each frequency component of the vibration generated in the string S, the higher the harmonic component becomes, the more
Rapidly decaying phenomena are faithfully simulated.

Excitation circuits +01 and 102 each generate an excitation signal corresponding to the excitation vibration imparted to the string S by the bow L.

Excitation circuit! 01 includes an adder 21, a divider 22, a nonlinear function generating circuit 23, and multipliers 24 and 25. In the adder 21, a delay circuit! ! output signal Vals, output signal va of the delay circuit 7, and signal V indicating the moving speed of the bow L.
A (hereinafter referred to as bow speed signal VA) is added. Here, the signals Va and Va, respectively indicate the vibration of the string S at the string rubbing position AI. Since it corresponds to the velocity components of the waves Wa and wb, the sum of these values corresponds to the velocity components of the string S at the string rubbing position A1.
corresponds to the speed of Then, the value obtained by further adding the bow speed signal VA to the above addition value, that is, the signal VAS (hereinafter referred to as , speed difference signal VAS
) is output from the adder 21. Here, the bow speed signal VA is the control unit!・Output from 03. This bow speed signal VA is generated by storing data indicating temporal changes in bow speed obtained by observing the movement of the bow L during actual violin performance in a memory (not shown) of the control unit 103, and generating a musical sound. It may be read out at the same time,
It may also be input using a special operator.

Divider 22, nonlinear function generation circuit 23, and multiplier 24
This circuit simulates the ability of the string S to follow the movement of the bow L. Divider 22 and multiplier 2
4 contains a signal F1 (hereinafter referred to as bow pressure signal F1) corresponding to the pressure exerted by the bow 1■ on the string S at the string rubbing position A1.
are provided as a division factor and a multiplication factor, respectively.

On the other hand, a bow pressure signal F corresponding to the string rubbing position A is applied to a corresponding location in the excitation circuit 102.

These bow pressure signals F, F, and the like are supplied from the control section 103 in the same manner as the bow velocity signal VA described above.

Here, in actual violin performance, the angle of the bow L with respect to the string S changes with time, so the string rubbing position A and A
The bow pressure at , also changes over time.

In this embodiment, taking this into consideration, the temporal changes in the bow pressure at the bow string positions AI and A are based on the temporal changes in the total pressure of the bow L and the temporal changes in the angle of the bow L with respect to the string S. data indicating the bow pressure signals Fl, F,
It is now output as . Note that the bow pressure signals F+ and F may be controlled in real time by operating special operators.

The nonlinear function generating circuit 23, as shown in FIG.
M4 1.4 2, a multiplier 43 and an adder 44. The output of the divider 22 shown in FIG. 1 is applied to both the ROMs 1 and 42 as the human power X. R
OM41 stores a table of nonlinear relation losses A whose contents are shown in FIG. As shown in the figure, input
If is in the range -Xs-X+n, the output Y of rtOM41 is -X; otherwise, the output Y of ROM41 is O. rLOM42 has a table of nonlinear function B shown in Fig. 5. remembered. As shown in the figure, if the input is in the range of -Xm to xal, rlOM4
The output Y of 1 is 0. Then, input X h < X m
When it exceeds , the output Y becomes a negative value, and thereafter, as the human power X increases in the positive direction, Y gradually approaches 0. Furthermore, when the input X becomes less than -xI1, the output Y becomes a positive value, and as the input X increases in the negative direction, Y gradually approaches 0. Then, the output of the 110M42 is multiplied by the bow pressure signal F, 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 as shown in FIG. 6 are obtained. As shown in the figure, the nonlinear function generating circuit 23 has an input X of -XIIl-X
In the interval IIl, the output Y (
= -X) is obtained, and in the section where the human power is smaller than 1X+a and the section where the human power can get.

A divider 22 is used for changing the stages of the nonlinear function generation circuit 23.
However, since the multiplier 24 is inserted in the latter stage, as shown in FIG. 7, the human output characteristics obtained by expanding the input/output characteristics of FIG. 6 in the X direction and the Y direction according to the bow pressure signal F1 are as shown in FIG. This is obtained as the input/output characteristics of the divider 22, nonlinear function generation circuit 23, and multiplier 24 as a whole.

When the absolute value of the speed difference signal VAS supplied from the adder 2l is small, the linear region S.
The output signal is determined accordingly, and VAM. An excitation signal V A M l of =-VAS is output from the multiplier 24 . Then, the excitation signal VAM. multiplier 25 to 1/
2 is multiplied, and the multiplication result (1/2) VAM. is adder I
2 and 8 are manually operated. As a result, the addition Va I 2
The output Vas is Vai=Va++(1/2)VAM
I-V at (1/2)V A S=V
a+ (1/2) (VA+VS) (1), and the output Va4 of the adder 8 is va4=vat+(1/2)vAM+ -Vat (1/2)VAS=Vat (1/ 2) (V A + V S
)...(2) becomes. However, in the above formulas (1) and (2),
VS is V a l + V a t, which corresponds to the speed of the string S when the effect of the bowed string is not considered. The signals Va= and va4 thus obtained are respectively input to the delay circuit 1 and the low-pass filter 9 as signals representing the vibration waves Wa and wb at the string rubbing position rllAI in which the effect of string rubbing is taken into account. Here, the sum of the signals Va and Vat is the string S when considering the effect of the rubbed strings.
This corresponds to the speed VSL of . In this case, V S L = V aa + V aa = V a++ V at (V A + V S
)=-VA ・・・・・・(3
). That is, the string S moves at the same speed as the bow L. In this embodiment, the positive direction in which the bow L moves and the positive direction in which the string S moves are defined as opposite directions. In this way, a static frictional force acts between the bow L and the string S, and an operation in which the string S completely follows the bow L and is displaced is simulated.

On the other hand, when the absolute value of the speed difference signal VAS increases, the excitation circuit 10! The operating points are from the straight line area S0 to the +11+ line area P. in FIG. Pt, P,... or Q.
,Q. , Q, . . . , and the values of these curve regions are output as the excitation signal V A M l.

Here, ■ line area P,, P,, P3, ... and Q,
, Q, , Q3, . . . correspond to a state in which the string S is displaced while sliding with respect to the bow L.

Here, as shown in FIG. 7, the point at which the linear region S0 transitions to the curved region moves away from the origin as the bow pressure signal FI increases. By doing this, a phenomenon is simulated in which the larger the suppressing force of the bow L, the better the following ability of the string S to the bow L becomes. In addition, the curve area to which the transition destination occurs is Z3, where the bow pressure signal F1 increases, and P. (Q
l)-Pt(Qt)-P3<Q3)-1. By doing this, even when the string S slips with respect to the bow L, a phenomenon is simulated in which the greater the pressing force of the bow L, the better the followability of the string S to the bow L becomes.

Then, the output signal V A M l of multiplication 524 is
It is divided into two by e25 and applied to adders 12 and 8. In this case, the value of the Ilil line region is the excitation signal VAM
．． Since the signals Va and Va, are used as
The signals V a-+ and Va, vary only slightly.

In this way, the operation when dynamic friction occurs between the bow L and the string S is simulated.

The excitation circuit +02 is also realized with the same configuration as the excitation circuit 10, and receives the bow speed signal VA and the bow pressure signal F supplied from the controller 103, the output signal vb of the delay circuit I, and the output signal of the delay circuit 5. An excitation signal VAMI is created based on the signals Vb and 1/2 thereof is supplied to adders 2 and 6.

The operation of this musical tone synthesis device will be explained below. Prior to the generation of musical tones, the delay circuits 1, 5, 7 .
1 1 delay time is set. In this case, the delay time of each delay circuit is set so that the time required for a signal to go around the closed loop circuit 100 is the reciprocal of the primary resonance frequency of the generated musical tone. The control unit 103 outputs the bow speed signal VA and the bow pressure signal F, the bow speed signal VA and the bow pressure signal FI are supplied to the excitation circuit 101, and the bow speed signal VA and the bow pressure signal F, Excitation circuit 1
02. Then, as described above, the excitation signal V8M1 is applied to the excitation circuit! Generated by 01, Part 1
72 is closed loop circuit +00 via adder I2 and 8
The excitation signal V A M t is input to the excitation circuit 102 .
, and 1/2 of it is input to the closed loop circuit +00 via adders 2 and 6.

The signals output from the excitation circuits +01 and +02 and introduced into the closed loop circuit 100 circulate within the loop and are re-input to the excitation circuits 101 and +02. This operation corresponds to the phenomenon in FIG. 2 that the vibration applied to the string S by the bow L propagates left and right from the stringing position, is reflected at each fixed end, and returns to the stringing position again. Thereafter, the excitation signals VAM and V A M t are similarly calculated by the excitation circuits +01 and 102,
The operation of inputting to the closed loop circuit 100 is repeated. The signal circulating through the closed loop circuit 100 is then extracted as a musical tone signal and sent to the sound system. A synthesized sound of the violin sound is produced.

In addition, in the above-mentioned embodiment, the case where two excitation circuits were provided for the string rubbing positions A1 and A was explained, but the AI
If an excitation circuit is added corresponding to each string position existing between As, more precise musical tone synthesis can be performed. Conversely, as in the above embodiment, the excitation circuits +01 and +02
Instead of preparing both, use only one excitation circuit,
Even if the output of the excitation circuit is manually applied to each position corresponding to the string rubbing positions A1 and A in the closed loop circuit 100, it is possible to obtain a synthesized sound that is close to the actual violin sound to some extent. In addition, in the above embodiment, the string rubbing position A
．． -A! Although delay circuits 1 and 7 having equal delay times are provided to accommodate the propagation delay between them, the delay times of both may be unbalanced, or one of the delay circuits may be omitted. In addition, a keyboard is connected to the musical tone matching device according to the above embodiment, and parameters such as the delay time distribution of delay circuits 1, 5, 7, and 1l, bow pressure signals F and F, and bow speed signal VA are input to the keyboard. It may be changed according to the initial touch, aftertouch, etc. when hitting.

For example, if the touch is strong, the delay time τ of the delay circuit I1
a is made small, the delay time τb of the delay circuit 5 is made large, the delay time τ1 of the delay circuits 1 and 7 is made large, and the bow pressure signals F1 and F are made large. In this way, a strongly expressive tone is achieved. Also,
If the touch is weak, the delay time τa of the delay circuit l1 and the delay time τb of the delay time 5 are made close to each other, and the delay circuit ! and 7 delay time τ1 is made smaller, and further the bow pressure signal F1 is
and F, are made small. In this way, a weakly expressed tone is achieved. In addition, depending on the key code of the generated musical tone, the delay time distribution of each delay circuit, bow pressure signal F,
and F, the bow velocity signal VA may be changed. Further, in the above embodiment, the present invention is applied to a musical tone synthesis device for a bowed string instrument, but similar effects can be obtained by applying the present invention to a plucked string instrument or a percussion instrument 4.

"Effects of the Invention" As explained above, according to the present invention, a natural musical instrument includes a sounding body and a sounding operator that excites a part of the sounding body and generates vibrations that propagate back and forth through the sounding body. A musical tone synthesizer for synthesizing musical tones includes a plurality of delay elements cascaded in a loop, and the delay time required for a signal to go around the loop is equal to the period in which vibrations propagate back and forth through the sounding body. and an excitation signal corresponding to an excitation vibration applied to the sounding body according to operation information of the sounding operator, each connected to each node selected so as to sandwich at least one delay element in the closed loop circuit. and an excitation means for calculating the excitation signal and supplying the excitation signal to the node, the effect is that musical tones of musical instruments in which excitation vibrations are introduced through a wide range of parts of the sounding body can be faithfully synthesized. is obtained.

[Brief explanation of the drawing]

Fig. I is a block diagram of a musical tone synthesizer according to an embodiment of the present invention, Fig. 2 is a diagram explaining the mechanism of introducing excited vibrations into violin strings, and Fig. 3 is a nonlinear diagram of the embodiment shown in Fig. 1. Block diagram showing the configuration of the correlation generation circuit 23, No. 4
7 to 7 are diagrams illustrating nonlinear functions used in the same embodiment. 100...Closed loop circuit, 101, 102...
. . . Excitation circuit, 103 . . . Control section. Outsourcer Yamaha Co., Ltd.

Claims (1)

[Scope of Claim] A musical tone synthesis device for synthesizing musical tones of a natural musical instrument comprising a sounding body and a sounding operator that excites a part of the sounding body and generates vibrations that propagate back and forth through the sounding body, comprising: a closed loop circuit in which a plurality of elements are cascaded in a loop shape, and a delay time required for a signal to go around the loop is equal to a period in which vibration propagates back and forth through the sounding body; It is connected to each selected node so as to sandwich at least one delay element, and calculates an excitation signal corresponding to the excitation vibration given to the sounding body according to the operation information of the sounding operator, and transmits the excitation signal to the node. What is claimed is: 1. A musical tone synthesis device, comprising: excitation means for supplying excitation.