JP3758474B2 - Musical sound synthesizer, musical sound synthesis method and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a musical sound synthesizer, a musical sound synthesis method, and a recording medium suitable for use in application programs in electronic musical instruments, amusement devices (karaoke, game devices, etc.), personal computers, and the like, and in particular, stringed musical instruments such as violins and violas. The present invention relates to a musical tone synthesizer suitable for use in simulation, a musical tone synthesis method, and a recording medium.
[0002]
[Prior art]
There are various types of stringed instruments such as stringed instruments such as violins and violas, percussion instruments such as pianos, and plucked instruments such as guitars. Among them, a physical model sound source that simulates the behavior of strings and bows in order to automatically synthesize a stringed instrument sound is known (Japanese Patent Publication No. 2719655, Japanese Patent Publication No. 7-21715, etc.). In these physical model sound sources, a closed loop circuit that simulates the behavior of a string and an excitation unit that supplies an excitation signal to the closed loop circuit to simulate the operation of rubbing the string with a bow are provided. It has been.
[0003]
In order to simulate the string vibration of an actual stringed instrument more precisely, the string vibration should be divided into, for example, a longitudinal vibration component along the protruding direction of the bridge and a transverse vibration component perpendicular to this. . When the string is energized in the direction of pressing the bridge in the longitudinal vibration (hereinafter referred to as the downward direction) (in the case of a bowed instrument, the bow pressure also acts as a bridge pressing force through the string), the string is substantially Become stiff. In other words, the string tension increases and the effective delay length decreases. On the contrary, when a string is energized in a direction away from the bridge (hereinafter referred to as an upward direction), since the restriction by the bridge is reduced, the effective delay length is increased.
[0004]
Thus, a technique for controlling the effective delay length in accordance with the direction of string vibration in simulation of a stringed musical instrument such as a piano has been proposed (Japanese Patent No. 2643717). There has also been proposed an electronic musical instrument that is provided with two closed-loop circuits corresponding to the above-described longitudinal vibration and lateral vibration and faithfully simulates the behavior caused by these vibrations (Japanese Patent Laid-Open No. 6-83363).
[0005]
[Problems to be solved by the invention]
As described above, in the prior art, the point of simulating the behavior due to the longitudinal vibration is disclosed, but all of them assume a state in which the string freely vibrates in a stringed musical instrument such as a piano. On the other hand, in the performance mode of a bowed instrument, the period during which the string freely vibrates is relatively short, and most of the strings are in contact with the bow. Therefore, unless the interaction between the longitudinal vibration and the bow motion is taken into consideration, the behavior of the bowed instrument cannot be accurately simulated, and it is difficult to reproduce the delicate nuances of the bowed instrument.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a musical tone synthesis apparatus, a musical tone synthesis method, and a recording medium that can perform precise modeling of a bowed instrument or the like with a simple configuration.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the musical tone synthesizer according to claim 1 is a circulation means for circulating a waveform signal while delaying it, an excitation means for generating an excitation signal based on performance operation information and supplying the excitation signal to the circulation means, A musical tone signal generating unit that generates a musical tone signal using a waveform signal ; and a delay amount setting unit that sets a delay amount in the circulation unit based on a polarity of the waveform signal and a polarity of the performance operation information. Features .
Et al is, in the configuration of claim 2, wherein, in the musical tone synthesizing apparatus according to claim 1, wherein said circulation means, said waveform signal based on the polarity of the polarity and the performance operation information of the waveform signal It characterized by having a filter means that determine a filter characteristic for delaying.
According to a third aspect of the present invention , there is provided a musical sound synthesizing method in which a waveform signal is circulated while being delayed in the circulation means, an excitation signal is generated based on performance operation information and supplied to the circulation means, and the waveform signal And a step of setting a delay amount in the circulating means based on the polarity of the waveform signal and the polarity of the performance operation information.
A recording medium according to claim 4 stores a program for executing the method according to claim 3 .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1. Configuration of Embodiment 1.1. Performance operation information generator 100
Next, the configuration of an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 100 denotes a performance operation information generation unit, which has a configuration with a bowed instrument and a bow, and outputs performance operation information in accordance with a user operation. Such performance operation information includes bow pressure Pb, bow speed Vb, tone color TC, and pitch PITCH. Such a performance operator is disclosed in, for example, Japanese Patent Laid-Open No. 5-006169 or Japanese Patent Laid-Open No. 10-078778. The bow speed Vb becomes a positive value when the bow is moved in a predetermined direction and becomes a negative value when the bow is moved in the reverse direction.
[0008]
1.2. Musical instrument model part 300
1.2.1. Linear part 320
Next, reference numeral 300 denotes a musical instrument model unit, which includes an excitation unit 310 and a linear unit 320 as shown in FIG. In the linear unit 320, a closed loop circuit for simulating the behavior of the string of a bowed instrument is formed by the delay circuits 12, 13, 15, 16, the termination filters 11, 14, the bridge filter 22, and the adders 17, 19. . A velocity signal indicating the string velocity is propagated in the closed loop circuit.
[0009]
In an actual bowed instrument, when vibration occurs at the contact point between the bow and the string, a traveling wave is generated toward the support points (two points) of the string. Each of the delay circuits 13 and 16 has a delay time corresponding to the delay time until this traveling wave reaches both support points. Further, in the bowed instrument, the traveling wave that has reached the two support points of the string is reflected while the polarity is reversed, and propagates toward the contact point between the bow and the string. Each of the delay circuits 12 and 15 has a delay time corresponding to the delay time until these reflected waves reach the contact point between the bow and the string.
[0010]
Further, the traveling wave and the reflected wave in the bowed instrument are attenuated in the process of propagating in the string and being reflected at the support point. The end filters 11 and 14 invert the polarity of the traveling wave as described above, and have pass characteristics that simulate attenuation in the strings and at the support points and their frequency characteristics. The bridge filter 22 applies different filtering characteristics to the traveling wave according to the vibration direction of the longitudinal vibration. Details thereof will be described later.
[0011]
The adder 18 adds the velocity signals output from the delay circuits 12 and 15, and thereby outputs a string velocity signal RETURN obtained by synthesizing the reflected waves from both ends of the string. An excitation signal DRIVE (details will be described later) output from the excitation unit 310 is applied to the adders 17 and 19. This simulates the speed applied from the bow to the string. A mixer 23 mixes the output signal of the adder 17, the output signal of the delay circuit 15, and the excitation signal DRIVE based on the mixing ratio control signal MIXERVL, and outputs the result as a tone signal VTONEOUT.
[0012]
1.2.2. Excitation unit 310
Next, 312 is a subtracter inside the excitation unit 310, and subtracts the bow speed Vb from the speed signal RETURN output from the adder 18, and outputs a relative speed RV between the bow and the string. Reference numeral 311 denotes a non-linear conversion unit which outputs an excitation signal DRIVE to be applied to the linear unit 320 based on the relative speed RV, the bow pressure Pb, and other parameters. That is, in an actual bowed instrument, the force applied to the bow is determined by the relative speed between the bow and the string and the bow pressure Pb. These relationships are non-linear. The non-linear converter 311 simulates the behavior of the string.
[0013]
1.3. Control unit 200
Next, reference numeral 200 denotes a control unit. When performance operation information is supplied from the performance operation information generation unit 100, various parameters of the linear unit 320 are set according to the performance operation information. That is, the control unit 200 sets the delay times DL1, DL2, DR1, DR2 in the delay circuits 12, 13, 15, 16 based on the pitch PITCH, and the filter characteristics TFL in the termination filters 11, 14 based on the tone color TC. The various constants in the bridge filter 22 and the distribution ratio of the delay times DL1, DL2, DR1, DR2 are set.
[0014]
1.4. Bridge filter 22
Next, the details of the bridge filter 22 provided in the linear section 320 will be described with reference to FIG. In the figure, 34 is an adder, 35 and 36 are D flip-flops, 37 is a multiplier, and 38 is a subtractor, and these constitute a variable delay circuit 43 (all-pass type digital filter). The variable delay circuit 43 delays the waveform signal output from the delay circuit 13 by a time corresponding to the coefficient COEF.
[0015]
Reference numeral 31 denotes a selector that outputs “0.5” when the bow speed Vb is a positive value and “−0.5” when the bow speed Vb is a negative value. A multiplier 32 outputs a multiplication result of the output signal of the selector 31 and the signal BRDG. Here, the signal BRDG is an output signal of the adder 34 constituting the variable delay circuit 43, and is obtained by cutting the high frequency component of the waveform signal output from the delay circuit 13.
[0016]
Next, 33 is a selector, which sets the coefficient COEF to “APUP” if the output signal of the multiplier 32 is a positive value, and sets the coefficient COEF to “APDOWN” if it is a negative value. Here, if the delay time of the variable delay circuit 43 set according to the coefficient COEF is set to DELAY [COEF], the delay time is set to satisfy DELAY [APDOWN] ≦ DELAY [APUP].
[0017]
Therefore, the coefficient COEF is selected according to the positive and negative polarities of the signal BRDG and the bow speed Vb. That is, when the polarity of the signal BRDG and the bow speed Vb are equal, the multiplication result in the multiplier 32 becomes a positive value, so APUP is selected as the coefficient COEF, and when the polarity is different, the multiplication result becomes a negative value. APDOWN is selected as the COEF. As described above, since the signal BRDG is equal to the waveform signal output from the delay circuit 13 which is cut out from the high frequency component, if the polarity of the low frequency component of the waveform signal coincides with the polarity of the bow velocity Vb, the coefficient COEF APUP is selected, and if it does not match, APDOWN is selected.
[0018]
A multiplier 39 multiplies the waveform signal delayed through the variable delay circuit 43 by the coefficient BFMIX. A multiplier 40 multiplies the waveform signal before being delayed by a coefficient “1-BFMIX”. Reference numeral 41 denotes an adder that adds the output signals of the multipliers 39 and 40. Reference numeral 42 denotes a multiplier that multiplies the waveform signal output from the adder 41 by “−1”.
[0019]
1.5. Resonance effect applying unit 400
Next, reference numeral 400 denotes a resonance effect applying unit that receives the musical tone signal VTONEOUT from the musical instrument model unit 300 and receives the bow velocity Vb, the bow pressure Pb, and the pitch pitch from the control unit 200 to resonate with the musical tone signal VTONEOUT. Is granted.
[0020]
Details of the resonance effect applying unit 400 are shown in FIG. In the figure, reference numeral 402 denotes a multiplier that multiplies the tone signal VTONEOUT by a volume control coefficient and outputs the result. Reference numeral 401 denotes a volume control coefficient supply unit that calculates the volume control coefficient based on the bow speed Vb, the bow pressure Pb, and the pitch Pitch. Reference numeral 403 denotes a resonance signal generation unit that simulates the resonance unit of the bowed instrument and applies a resonance effect to the output signal of the multiplier 402.
[0021]
Next, 404 is an output mixer, which mixes the resonance signal supplied from the resonance signal generator 403 and the tone signal VTONEOUT before the resonance effect is applied, and outputs the result as the final tone signal TONEOUT. To do. This musical tone signal TONEOUT is produced via a sound system (not shown).
[0022]
2. Operation of Embodiment 2.1. General Operation Next, the operation of this embodiment will be described.
When the user operates the performance operation information generation unit 100, the timbre TC and the pitch PITCH are supplied to the control unit 200, the bow pressure Pb is supplied to the non-linear conversion unit 311, and the bow speed Vb is supplied to the subtractor 312. The Based on the tone color TC and the pitch PITCH, the delay times DL1, DL2, DR1, DR2 and the filter characteristics TFL, TFR in the linear unit 320 are determined.
[0023]
When the bow speed Vb is supplied to the subtractor 312, the result obtained by subtracting the bow speed Vb from the speed signal RETURN is supplied to the nonlinear conversion unit 311 as a relative speed RV. Here, since the speed signal RETURN is “0” in the initial state, the inverted signal of the bow speed Vb is supplied to the nonlinear conversion unit 311 as it is.
[0024]
In the non-linear converter 311, an excitation signal DRIVE corresponding to the force applied to the bow is output based on the bow pressure Pb, the relative speed RV, and the like. In the initial state, the speed signal output from the delay circuits 12 and 15 in the closed loop circuit is “0”. For this reason, the excitation signal DRIVE is supplied to the delay circuits 13 and 16 as a velocity signal that forms a traveling wave as it is. These speed signals are delayed through the delay circuits 13 and 16, subjected to filtering processing through the termination filters 11 and 14 and the bridge filter 22, and then formed into reflected waves through the delay circuits 12 and 15. The signals are supplied to adders 17 and 19 as signals.
[0025]
These speed signals are combined in the adder 18 and then fed back to the subtractor 312 as the speed signal RETURN. Accordingly, the bow speed Vb at the time of feedback from the speed signal RETURN is subtracted, and this result is supplied as a new relative speed RV to the non-linear converter 311, and the excitation signal DRIVE based on this relative speed RV is added to the adder 17, 19 is again supplied to the closed loop circuit.
[0026]
When the above processing is repeated with the parameters such as the bow speed Vb being constant, each speed signal, speed signal RETURN and excitation signal DRIVE in the closed loop circuit will eventually become standing waves having a constant and stable pitch. . When the speed signal in the closed loop circuit is supplied to the sound system via the mixer 23 and the resonance effect applying unit 400, a tone having this pitch is generated.
[0027]
2.2. Operation in the bridge filter 22 In the bridge filter 22, a relatively short delay time DELAY [APDOWN] for one polarity of the signal BRDG and a relatively long delay time DELAY [APUP] for the other polarity are variable delays. It is given to the circuit 43. Therefore, the waveform signal propagated in the linear unit 320 is given distortion based on the difference in delay time for each polarity.
[0028]
As described above, in the longitudinal vibration of an actual stringed instrument, when the string is energized downward, the string becomes stiff and the effective delay length is shortened. Conversely, when the string is energized upward, the effective delay length increases. Since the distortion imparted to the waveform signal by the bridge filter 22 of the present embodiment corresponds to the distortion generated in such an actual stringed instrument, it is possible to generate a faithful musical sound that is closer to a natural instrument.
[0029]
Further, in the present embodiment, the selector 31 and the multiplier 32 switch the selection state of the selector 33 according to the polarity of the bow speed Vb. The reason is explained here. In order to simulate the behavior of an actual stringed instrument due to longitudinal vibration, it is theoretically sufficient to switch the coefficient COEF based only on the signal BRDG. However, when the bow is returned in the performance operation information generation unit 100, the relative speed (movement) direction of the bow and the string is reversed. In this case, in order to prevent the occurrence of discontinuous noise or unnecessary timbre changes, the polarity of the bow speed Vb is also taken into account when selecting the coefficient COEF.
[0030]
3. As described above, according to the present embodiment, the delay time DELAY in the variable delay circuit 43 is switched in accordance with the polarity of the waveform signal in the linear unit 320 and the polarity of the bow speed Vb. The behavior of longitudinal vibration is simulated, and precise modeling of a bowed instrument can be performed with a simple configuration.
[0031]
4). Modifications The present invention is not limited to the above embodiment, and various modifications are possible as follows, for example.
(1) In the above embodiment, the frequency characteristics of the strings are simulated by the end filters 11, 14, but the delay circuits 12, 13, 15, 16 are distributed constant circuits (string three-dimensionality, ie, string thickness and cross section). A more accurate simulation may be performed by simulating the delay and frequency characteristics of the strings by configuring each delay with an FIR filter structure in consideration of the shape and the like.
[0032]
(2) In the above embodiment, the elements such as the delay circuit and the arithmetic circuit are configured by hardware. However, some or all of these elements may be realized by software. Of course, if all the configurations shown in the hardware block diagram are realized by a program, the present invention can be realized by a general-purpose personal computer or the like. In such a case, the present invention can also be realized as a recording medium storing a program describing the operation of each element.
[0033]
(3) In the above embodiment, in order to simulate the behavior of a bowed instrument, the delay time DELAY is given the relationship “DELAY [APDOWN] ≦ DELAY [APUP]”. There is no need to maintain such a magnitude relationship.
[0034]
(4) In the configuration of FIG. 4, the selection result of the selector 31 based on the bow speed Vb is multiplied by the signal BRDG to determine the selection state of the selector 33. However, the selection state of the selector 33 is determined based on the exclusive OR of the bow speed Vb, which is digital data, and the most significant bit of the signal BRDG (“0” for positive, “1” for negative). May be.
[0035]
(5) In the configuration of FIG. 4, the coefficient COEF is switched instantaneously. However, in order to reduce noise at the time of switching, the coefficient COEF may be gradually changed by performing interpolation processing or the like.
[0036]
(6) In the above embodiment, APUP and APDOWN may be determined based on the pitch Pitch or the bow pressure Pb. The coefficient BFMIX that determines the contribution of the variable delay circuit 43 may also be determined based on the pitch Pitch or the bow pressure Pb.
[0037]
(7) In the above embodiment, when the polarity of the bow speed Vb changes, the selection state of the selector 31 is switched immediately and the selection state of the selector 33 is switched. However, in an actual bowed instrument, the change in the behavior of the string due to the return of the bow is reflected in the musical tone after propagating from the bowed point to the bridge over a certain period of time. This propagation time corresponds to the delay time DR1 in FIG. Therefore, a delay circuit having the delay time DR1 may be inserted at the selection input terminal of the selector 31, and the bow speed Vb may be supplied to the selector 31 via this delay circuit.
[0038]
(8) In the above embodiment example, the subject is string vibration simulation (physical model) of a bowed instrument, but in the case of string vibration simulation of a plucked string instrument or a stringed instrument that is common in that musical sound is generated by the vibration of the string. Applicable. For example, in the case of a plucked string instrument simulation, the bow speed Vb and the bow pressure Pb of the bowed string instrument in the embodiment of the present application may be replaced with the moving speed of the finger or pick to pluck or the force applied. In the case of a simulation of a stringed instrument such as a piano, Vb and Pb may be replaced with the speed of the string hammer and its acting force.
[0039]
【The invention's effect】
As described above, according to the present invention, since the delay amount in the circulation means can be set based on the relationship between the waveform signal and the performance operation information, for example, the mutual relationship between the vertical vibration of the string and the movement of the bow in the bowed instrument. The operation can be simulated, and precise modeling of a bowed instrument or the like can be performed with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.
FIG. 2 is a block diagram of a resonance effect applying unit 400. FIG.
3 is a block diagram of a musical instrument model unit 300. FIG.
4 is a block diagram of a bridge filter 22. FIG.
[Explanation of symbols]
11, 14 Terminal filter (circulation means)
12, 13, 15, 16 Delay circuit (circulation means)
17, 19 Adder (circulation means)
22 Bridge filter 23 Mixer (musical sound signal generating means)
31, 33 selector (delay amount setting means)
32 multiplier (delay amount setting means)
43 Variable delay circuit (delay amount setting means)
310 Excitation unit (excitation means)

Claims (4)

A circulation means for circulating the waveform signal while delaying,
Excitation means for generating an excitation signal based on the performance operation information and supplying it to the circulation means;
A musical sound signal generating means for generating a musical sound signal using the waveform signal;
Musical tone synthesizing apparatus characterized by having a delay amount setting means for setting a delay amount in the circulation means based on the polarity of the polarity and the performance operation information of the waveform signal. The circulation means, a musical tone according to claim 1, characterized in that it comprises a filter means that determine a filter characteristic for delaying the waveform signal based on the polarity of the polarity and the performance operation information of the waveform signal Synthesizer. A process of circulating the waveform signal while delaying in the circulation means;
A process of generating an excitation signal based on performance operation information and supplying it to the circulating means;
Generating a musical sound signal using the waveform signal;
Tone synthesis method characterized by having the steps of the setting the delay amount in the circulation means based on the polarity of the polarity and the performance operation information of the waveform signal. A recording medium storing a program for executing the method according to claim 3 .

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