JPH03163598A - Musical sound synthesizer device - Google Patents

Abstract

PURPOSE:To synthesize musical sound in which oscillations are reflected and which have high reality by taking signals respectively out of at least two points in a musical sound forming means, mixing the respective signals at a desired mixing ratio and outputting the same as a musical sound signal. CONSTITUTION:This device has a closed loop circuit 100 which simulates the string of a violin, an excitation circuit 101 which generates the excitation signal corresponding to the excited oscillations that a bow applies to the string, a mixing section 102 and a control section 103. The mixing section 102 consists of multipliers 31, 32 and an adder 33. The speed difference signal VAS is multiplied by the coefft. gamma1 of multiplication by a multiplier 31 and the signal (1/2)VAM is multiplied by the coefft. gamma2 of multiplication by a multiplier 32. These signals are added by an adder 33 and are outputted as the musical sound signal. The signals are taken out of at least the two points of the closed loop circuit 100 in such a manner and since the respective signals are mixed at the desired ratio, the musical tones in which the oscillations of the respective parts of the sound producing body of a natural musical instrument are reflected and which have the high reality are thus synthesized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a musical tone synthesis device that faithfully synthesizes musical tones of natural musical 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. As a musical sound synthesis device for stringed instrument sounds, there is a known device in which a low-pass filter that simulates the acoustic loss of strings and a delay circuit that simulates the propagation delay of vibrations in the strings are connected in a closed loop. There is. 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 each time it passes through the low-pass filter.

The signal circulating in this closed loop is extracted and output as a musical tone signal. 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 string instrument such as a guitar, the sound of a percussion instrument such as a piano, etc.
It is possible to synthesize musical sounds that are somewhat similar to natural string instrument sounds. Further, a musical tone synthesis device for the sound of a bowed string instrument such as a violin is realized by connecting an excitation circuit that calculates vibrations excited in a string by a bow to a closed loop circuit similar to that described above. Note that this type of technology is known, for example, from Japanese Unexamined Patent Publication No. 6
Publication No. 3-40199 or Special Publication No. 58-58679
It is disclosed in the publication No.

``Problems to be Solved by the Invention'' Now, in the case of actual natural musical instruments, the vibrations of the entire sounding body, such as the strings in a stringed instrument or the windshield in a wind instrument, are radiated into the air and are heard as musical sounds by the listener. For example, in the case of guitar strings, the content ratio of high-frequency components in the vibrations of the string differs between near the bridge and in the center, and unless musical tone synthesis is performed that reflects the vibrations of each part of the string, it will not be possible to create a realistic sound. I can't get a rich musical tone. However, the conventional musical tone synthesis device described above extracts a musical tone signal from one specific point within a closed loop, and therefore cannot faithfully reproduce the natural musical instrument sound generated by the vibration of the entire sounding body. There was a problem.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a musical tone synthesis device capable of synthesizing a musical tone that reflects the vibrations of each part of a sounding body and is rich in arity.

"Means for Solving the Problems" In order to solve the above problems, the present invention provides an excitation means for generating an excitation signal, and a musical tone forming means to which the excitation signal is input, which is composed of a closed loop circuit including at least a delay element. , a mixing means for extracting signals from at least two points in the musical tone forming means, mixing the respective signals at a desired mixing ratio, and outputting the mixed signal as a musical tone signal.

"Operation" According to the above configuration, at least two
Since signals are extracted from each point and mixed at a desired ratio, musical tones that reflect the vibrations of each part of the sounding body of a natural musical instrument and are rich in quality are synthesized.

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

No.! FIG. 1 is a block diagram showing the configuration of a musical tone synthesis device according to an embodiment of the present invention. This musical tone synthesis device synthesizes violin sounds, and includes a closed loop circuit +00 that simulates violin strings, an excitation circuit l01 that generates an excitation signal corresponding to the excitation vibration that a bow gives to the strings, a mixer circuit 102, and It consists of a control section +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,
L indicates a bow. Also, the fixed end T1 that fixes both ends of the string S
and T, correspond to the nut and bridge of the violin, respectively. When bow L is pressed against string S and played (arrow U), bow L
The string S moves with the movement of the bow L, and when the elastic force of the string S exceeds the static friction force, the string S moves with the movement of the bow L. S slides against the bow L and tries to return to its original position. In this way, bow L
vibration is excited in the string S.

In reality, since the bow L is made up of a large number of bundles of hairs, the above-mentioned vibration is excited at each string position where the string S and one hair are in contact with each other.

The vibration excited in the string S at the string rubbing position is split into two,
It propagates to the fixed end T1 side as a vibration wave Wa, and also propagates to the fixed end T side as a vibration wave Wb. The vibration wave Wa is phase-inverted and reflected at the fixed end T, and the reflected wave propagates toward the fixed end T, and the vibration wave wb is
It is phase-inverted and reflected at the fixed end T, and the reflected wave propagates toward the fixed end T. And the string S is a vibration wave W
Fixed end TI and T obtained by adding a and wb,
It vibrates according to a standing wave Ws whose nodes are .

The loop circuit 100 in FIG. 1 simulates the vibration propagation mechanism in the string S as described above, and is a delay circuit! , adder 2, low-pass filter 3
, a phase inversion circuit 4, a delay circuit 5, an adder 6, a low-pass filter 7, and a phase inversion circuit 8.

Delay circuits (1) and (5) each have a configuration in which delay time can be adjusted, and the delay time is controlled by control 1103. 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. Here, the delay time τa of the delay circuit I is set in accordance with the time required for the vibration wave Wa to reciprocate from the string rubbing position to the fixed end T on the string S. Further, the delay time τb of the delay circuit 5 is set to match the time required for the vibration wave wb to travel back and forth from the string S position to the fixed end T.

The phase inversion circuits 4 and 10 are provided to simulate a phenomenon in which the phases of the vibration waves Wa and wb are inverted at the fixed ends T and T, respectively. Furthermore, the low-pass filters 3 and 7 are inserted to simulate the frequency characteristics of vibration damping in the string S. By intervening these, each frequency component of the vibration generated in the string S becomes a high-order, high-wave component.
Rapidly decaying phenomena are faithfully simulated.

The excitation circuit 101 generates an excitation signal corresponding to the excitation vibration given to the string S by the bow, and includes an adder 21, a divider 22, a nonlinear function oscillation circuit 23, and a multiplier 2.
Consists of 4 and 25. In case N7.2H21, the output signal Va of the delay circuit 1, the output signal Va of the delay circuit 5, and the signal VA indicating the moving speed of the bow L (hereinafter referred to as the bow speed signal V
A) is added. Here, the signal Va. and V
a, are the vibration waves Wa at the string rubbing position A1 of the string S, respectively.
and wb, the sum of these values corresponds to the velocity of the string S at the string rubbing position A. Then, a value obtained by further adding the bow speed signal VA to the above added value,
In other words, the signal V corresponds to the tentative relative speed between the bow L and the string S when it is assumed that the string S does not follow the bow L at all.
AS (hereinafter referred to as speed difference signal VAS) is output from the adder 2l. Here, the bow speed signal VA is control +03
is output from. Namely, the control section! The memory (not shown) of 03 stores data indicating temporal changes in bow speed obtained by observing the movement of the bow L during actual violin performance, and this data is read out when a musical tone is generated. , are sequentially supplied to adder 621 as bow velocity signal VA.

Divider 22, nonlinear function generation circuit 23, and multiplier 24
This circuit simulates how the string S follows the movement of the bow L. Divider 22 and multiplier 2
4, a signal F (hereinafter referred to as a bow pressure signal F) corresponding to the pressure of the bow L pressing the string S at the string rubbing position is shown.
Supplied as division and multiplication factors. This bow pressure signal F is also supplied from the control section +03 like the bow speed signal VA described above.

The nonlinear function generating circuit 23, as shown in FIG.
It is composed of 0Ms 41 and 42, a multiplier 43, and an adder 44. The output of the divider 22 shown in FIG. 1 is applied as input X to both ROMs 41 and 42. 11
0M41 stores a table of nonlinear functions A whose contents are shown in FIG. As shown in the figure, input
is in the range of -Xm=Xm, the output Y of ROM41 is -X; otherwise, the output Y of ROM41
becomes 0. ROM42 has a nonlinear relationship r shown in FIG.
A table of lI13 is stored. As shown in the figure, when the human power X is in the range of -xIl-XII1, the ROM
The output Y of 4 1 is O. And input X is XlI1
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. Further, when the input X becomes less than 1X+a, 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 ROM 42 is multiplied by the bow pressure signal F by the multiplier 43, and the multiplication result and R
The output of OM41 is added by addition 444.

Therefore, the human output characteristic of the entire nonlinear function generating circuit 23 as shown in FIG. 6 is obtained. As shown in the figure, the nonlinear function generating circuit 23 has an input X of -XIIl-XII
In the interval 1, the output Y according to the nonlinear function A (=-
X) is obtained, and in the section where the human power X is smaller than -xII1 and the section where the input X is larger than XII1, an output Y is obtained by expanding the nonlinear function B in the Y-axis direction according to the value of the bow pressure signal F.

In the preceding stage of the nonlinear function generation circuit 23, a division 422 is provided.
However, since the multiplier 24 is inserted in the latter stage, as shown in FIG. 7, the human output characteristic obtained by expanding the human output characteristic in FIG. 6 in the X direction and Y direction according to the bow pressure signal F is as follows. Division 2
322 is obtained as the human output characteristic of the nonlinear function generating circuit 23 and the multiplier 24 as a whole.

When the absolute value of the speed difference signal VAS is small, the output signal is determined according to the linear region S0 in the human output characteristics in FIG.
is output from. Then, a multiplier 25 is applied to the excitation signal VAM.
is multiplied by 1/2, and the multiplication result (1/2) VAM
is input to adders 2 and 6. As a result, adder 2
The output Va, is: Vas = Va, + (1/2) VAM = Va + - (1/2) VAS = Va + (1/2) (VA
+V S )...(1), and the output Vaa of the adder 6 is Va. =Vat+(1/2)VAM=vat(1/2)VAS=V
at (I/2) (VA+VS) (2) Tomuru. However, in the above formulas (1) and (2),
VS is Va++Vat, which corresponds to the speed of the string S when the effect of string rubbing is not considered. The signals Va and va4 thus obtained are input to the low-pass filters 3 and 7 as signals representing vibration waves Wa and wb, respectively, in which the effect of string rubbing is taken into consideration. Here, the signal Va. The sum of and Van corresponds to the velocity of the string S when considering the effect of the bowed string, and in this case, V S L = V a3 + V aa = val + v
af-(VA+VS) =-VA (3).

Of course, 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 facing the road. In this way, static frictional force acts between the bow L and the string S, and the operation in which the string S completely follows the bow and is displaced is simulated.

On the other hand, when the absolute value of the speed difference signal VAS increases, the operating point of the excitation circuit 101 is in the linear region S in FIG. From the curve area P,,P,,P,,... or Q. ,Q
, Q, . . . , and the values of these curve regions are output as the excitation signal VAM.

Here, the 1111 line area P. ,P,,P. , ... and Q. Q, , Q, . . . correspond to a state in which the string S is displaced while sliding with respect to the bow.

Here, the straight line area S. As shown in FIG. 7, as the bow pressure signal F increases, the point at which the curve changes from to the midline region moves away from the origin. By doing this, the bow L
A phenomenon is simulated in which the greater the pressing force, the better the string S follows the bow L. In addition, in the region of the ■ line, which is the transition destination, as the bow pressure signal F, increases, P l(Q I
) − P t (Qt) − P 3 (Q 3) →. By doing this, it is possible to simulate a phenomenon in which when the string S slips with respect to the bow L, the greater the pressing force of the bow L, the better the string S follows the bow L.

And multiplication? The output signal VAM of A24 is divided into two by multiplier 25 and applied to adders 2 and 6. In this case, since the value of the rib area is used as the excitation signal VAM, the signals Vas and Va. is the signal Va+ and V
There is only a slight change from a. In this way, the operation when dynamic friction occurs between the bow L and the string S is simulated.

Mixer 102 consists of multipliers 31, 32 and adder 33. The speed difference signal VAS described above is multiplied by a multiplication coefficient 71 in a multiplication 431, and a signal (+/2) VAM is obtained.
is multiplied by the multiplication coefficient γ, by the multiplier 32,
The multiplication results of multiplications 531 and 32 are added by an adder 33, and the added antagonism is output as a musical tone signal. Here, the multiplication coefficient γ. γ, is determined by the control unit +03,
It is determined according to the operation state of a tone color operator (not shown).

And, before the musical tones begin, the mixing section! 02 will be forfeited.

The operation of this musical tone synthesis device will be explained below. Prior to the generation of musical tones, the delay time of the delay circuit 1.5 is set in the control section +03. 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.

Then, the bow speed signal VA and the bow pressure signal F are outputted from the controller 103 and supplied to the excitation circuit 101. Then, as described above, the excitation signal VAM is transmitted to the excitation circuit 10.
1 and 1/2 of which is input to the closed loop circuit l00 via adders 2 and 6.

Then, it is output from the excitation circuit 101, and the closed loop circuit +
The signal introduced into 00 circulates within the loop and is re-inputted into the excitation circuit 101. This operation corresponds to the phenomenon in FIG. 2 in which the vibrations applied to the string S by the bow propagate from the stringing position to the left and right, are reflected at each fixed end, and return to the stringing position again. Thereafter, the operation of calculating the excitation signal VAM by the excitation circuit 101 and manually inputting it to the closed loop circuit 100 is repeated.

Now, the signal circulating through the closed loop circuit 100 is limited by {]} by the low-pass filter 3.7.

Therefore, the signal Va taken from the closed loop circuit +00
Speed difference signal VAS created based on + and Va,
has few harmonic components. In contrast, the excitation signal VAM
Since the human output response of the excitation circuit 101 is nonlinear,
Contains many harmonic components.

In this musical tone synthesizer, the signal VAS and the signal (1/2) V
AM and AM are mixed by the mixing section 102 and output as a musical tone signal. Therefore, by adjusting the ratio of the coefficients γ, , γ, by operating a timbre operator (not shown) connected to the control unit +03 described above, a musical tone containing harmonic components at a desired content ratio can be obtained.

Note that in the embodiment described above, two signals VAS and V
Although the case where AM is mixed and outputted has been described, signals may be extracted from more positions in the device, mixed, and outputted.

"Effects of the Invention" As explained above, according to the present invention, there is provided an excitation means for generating an excitation signal, a musical tone forming means comprising a closed loop circuit in which the excitation signal is manually generated and includes at least a delay element, and a musical tone forming means that generates an excitation signal. Since the mixing means is provided for extracting signals from at least two points in the shaping means, mixing the signals at a desired mixing ratio, and outputting the mixture as a musical tone signal, natural music 4 can be achieved.
The effect is that the vibrations of each part of the sounding body are reflected, and musical tones rich in quality can be synthesized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a musical tone synthesizer according to an embodiment of the present invention, FIG. 2 is a diagram illustrating 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 function generation circuit 23, No. 4
7 to 7 are diagrams illustrating nonlinear functions used in the same embodiment. 100...Closed loop circuit, 101...
Excitation circuit, +02...Mixing section, 103...
...Control unit.

Claims (1)

[Scope of Claims] An excitation means for generating an excitation signal; a musical tone forming means to which the excitation signal is input and which is composed of a closed loop circuit including at least a delay element; and a musical tone forming means each receiving signals from at least two points within the musical tone forming means. What is claimed is: 1. A musical tone synthesizing device comprising: a mixing means for extracting signals, mixing each signal at a desired mixing ratio, and outputting the mixed signal as a musical tone signal.