JP2504324B2 - Music synthesizer - Google Patents

Description

The present invention relates to an apparatus for simulating a wind instrument,
In particular, the present invention relates to a musical sound synthesizer capable of faithfully reproducing wind instrument sounds accompanied by noise.

"Prior Art" In recent years, various devices have been developed that operate a model that simulates the sounding mechanism of a natural musical instrument to synthesize the musical sound of the natural musical instrument. This type of technique is disclosed in, for example, Japanese Patent Laid-Open No. 63-40199 or Japanese Patent Publication No. 58-58679.

FIG. 9 shows the configuration of a musical sound synthesizer that simulates the sounding mechanism of a government instrument. In this figure, 11 is a ROM (read only memory), 12 is an adder, and 1
3 is a subtracter, and 14 and 15 are multipliers. These components 11 to 15 are for simulating the operation of a portion consisting of a mouthpiece and a reed of a wind instrument such as a clarinet, and these constitute an excitation circuit 10.

Reference numeral 20 is a bidirectional transmission circuit that simulates the transmission characteristics of a wind instrument, that is, the resonance tube. The bidirectional transmission circuit 20 includes delay circuits D, D, ... Simulating a propagation delay of an air pressure wave in a resonance tube, junctions JU, JU ,. The low pass filter LPF that simulates energy loss and the like when the air pressure wave is reflected in the section, and the high pass filter HPF that blocks the DC component of the data propagating in the bidirectional transmission circuit 20. This junction JU, JU, ...
Is for simulating the scattering of air pressure waves generated in the resonance tube where the diameter of the tube is changing. In FIG. 9, multipliers M _{1 to} M ₄ and adders A ₁ and A _{2 are shown.} The case of using a 4-multiplication lattice consisting of Where each multiplier
“1 + k”, “−k”, “1-k”, “k”, etc. attached to M _{1 to} M ₂ are multiplication coefficients, and the numerical value k is set so that the transmission characteristic close to that of an actual resonance tube can be obtained. Can be decided

In such a configuration, the data P corresponding to the blowing pressure is input to the adder 12 and the subtractor 13. And
The output data of the adder 12 is stored inside the bidirectional transmission circuit 20,
The delay circuit D → junction JU → delay circuit D → ... Propagates and reaches the low-pass filter LPF. Then, after passing through the low-pass filter LPF and the high-pass filter HPF, the signal propagates in the opposite direction to the delay circuit D → junction JU → ... And is output from the bidirectional transmission circuit 20 and input to the subtracter 13. .

Then, the subtracter 13 subtracts the data P from the output data of the bidirectional transmission circuit 20 (this data corresponds to the pressure of the air pressure wave returned to the gap between the mouthpiece and the lead from the end side of the resonance tube). To be done. By this subtraction,
Data P ₁ corresponding to the air pressure in the gap between the lead and the mouthpiece is obtained. By supplying the data P ₁ to the ROM 11, the ROM 11 outputs the data Y corresponding to the cross-sectional area of the gap between the lead and the mouthpiece, that is, the admittance to the air flow. Figure 10 shows RO
6 is a diagram illustrating a non-linear function A indicating the relationship between the air pressure (input) in the gap between the lead and the mouthpiece, which is stored in M11, and the cross-sectional area (output) of the gap.

Such data Y and data P ₁ are multiplied by the multiplier 14, and as a result, data FL corresponding to the flow velocity of the air passing through the gap between the lead and the mouthpiece is obtained.
The data FL is multiplied by the multiplication coefficient G by the multiplier 15. Here, the multiplication coefficient G is a constant that is determined according to the diameter of the pipe in the vicinity of the lead attachment portion of the wind instrument, and corresponds to the difficulty of passing the air flow, that is, the impedance to the air flow. Therefore, from the multiplier 15, it corresponds to the product of the flow velocity of the air flow passing through the gap between the mouthpiece and the lead and the impedance with respect to the air flow of the tube portion, that is, the pressure change in the pipe due to the air flow passing through the gap. Data P ₂ is obtained. And this data P ₂ and data P
And are added by the adder 12 and input to the bidirectional transmission circuit 20.

In this way, in the closed loop composed of the excitation circuit 10 and the bidirectional transmission circuit 20, data circulation, that is,
Resonant operation is performed and a low-pass filter for the bidirectional transmission line 20.
The LPF connection point data is extracted, and a musical tone is generated based on this data.

By the way, in an actual wind instrument, there is a rendition style called subtone. This subtone is a performance style in which the noise component generated when breathing into the gap between the lead and the mouthpiece is exaggerated. Traditionally, the synthesis of such noise is
This is performed by superimposing data corresponding to noise on data P corresponding to the blowing pressure.

[Problems to be Solved by the Invention] However, the above-described noise component causes turbulent flow in the gap between the mouthpiece and the reed by blowing air, and the air pressure wave in the tube is caused by this turbulent flow. It is disturbed, and this is generated as noise. Therefore, the conventional noise reproduction method described above, that is, simply superimposing data corresponding to noise does not match the actual noise generation mechanism, and the noise generated by this method lacks naturalness. There was a flaw.

The present invention has been made in view of the above-mentioned circumstances, and provides a musical tone synthesizing device conforming to an actual noise generating mechanism, and an object of the present invention is to faithfully reproduce a noise effect when playing a wind instrument. There is.

[Means for Solving the Problems] The invention according to claim 1 is an excitation means for generating an excitation signal, and a loop means for delaying an input signal of itself for at least a predetermined time and for repeatedly circulating the excitation signal. In a musical sound synthesizer configured to use the circulating signal of the loop means as a musical sound signal, a noise generating means for generating a noise signal, and a noise signal generated by the noise generating means in accordance with the excitation signal. Noise control means for controlling the characteristics of the above, and a noise superimposing means for superimposing a noise signal generated by the noise generating means on a circulating signal circulating in the loop means and outputting the superimposed signal to the loop means. However, a noise signal having a characteristic corresponding to the excitation signal is superimposed on the circulation signal circulating in the loop means. The invention according to claim 2 is the invention according to claim 1, wherein the noise control means is responsive to the excitation signal and a circulating signal circulating through the loop means. It is characterized by controlling the characteristics of the noise signal generated by.

[Operation] According to the above configuration, the noise control means controls the characteristics of the noise signal according to the excitation signal, so that the noise generation means generates a noise signal that approximates the turbulent flow in the tube, and the noise superposition means causes the loop means. The noise signal is superimposed on the circulating signal circulating in the. As a result, musical tone synthesis is performed in accordance with the actual noise generation mechanism.

[Examples] Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall construction of a musical sound synthesizer according to an embodiment of the present invention. In this figure, 1
Is an operator that imitates a wind instrument such as a clarinet, and generates various signals according to the operation of the wind instrument player. Here, the configuration of the operator 1 will be described with reference to FIGS. 2 and 3.

First, FIG. 2A is an external view showing an example of the operator 1. In the figure, 1a is a key switch for generating a key-on signal Kon and a key-off signal Koff. 1b is a mouthpiece, inside of which a cantilever 1c and a pressure sensor 1d are provided as shown in FIG. The cantilever 1c detects and outputs the pressure applied to the reed when the wind player holds the mouthpiece 1b (this pressure is called embouchure). Meanwhile, pressure sensor
1d detects and outputs the breath pressure blown into the mouthpiece 1b by the wind instrument player.

As shown in FIG. 3, the manipulator 1 having such a configuration supplies the above-mentioned respective detection signals to the microcomputer 5. This microcomputer 5 is shown in FIG.
It is composed of a CPU2, a ROM3, a RAM4 and an AD converter (not shown). The microcomputer 5 having such a configuration converts the signals supplied from the key switch 1a, the cantilever 1c, and the pressure sensor 1d into digital data and then performs processing such as scaling to generate various data. Of these data, the key-on Kon / key-off Koff data is generated by determining whether or not the output signal of the pressure sensor 1d is equal to or higher than a predetermined value. The cent value data C is data representing a pitch and is generated based on a key code corresponding to the operation of the key switch 1a. The breath pressure data P is generated according to the output signal of the pressure sensor 1d, and is modified by the embouchure data E obtained from the cantilever 1c so as to give a feeling of blowing.

Next, the configuration of the embodiment will be described with reference to FIG. 1 again. In the figure, 6 is a noise generator, which generates the noise data N for reproducing the above-mentioned subtone and breath leak sound. The noise data N is used to simulate a turbulent flow phenomenon in the gap between the mouthpiece and the lead, which will be described later. The configuration of the noise generator 6 will be described later. Reference numeral 7 denotes a reed portion, which simulates the operation of the wind instrument mouthpiece and reed portion. 8 is the tube part of the wind instrument, that is,
It is a tubular part that simulates the transmission characteristics of a resonance tube. Then, these constituent elements 6 to 8 constitute a musical sound synthesis circuit 9.

Next, the configuration of the musical tone synthesis circuit 9 will be described with reference to FIG. In addition, in this figure,
The parts corresponding to those in the figure are designated by the same reference numerals. This tone synthesis circuit 9 includes an excitation circuit 10, a junction 22,
And a tube forming circuit 20. The excitation circuit 10 is
Subtractor 13, adders 16,33, multipliers 31,32,34, ROM11a, 11b
And a filter 30a, 30b, which is a circuit for simulating a mouthpiece part of a wind instrument. Junction
22 is composed of adders 22a and 22b. Tube forming circuit 20
Is a circuit for simulating a resonance tube in a wind instrument, the details of which will be described later.

First, in the junction 22, the output data of the multiplier 34 and the tube forming circuit 20 are added by the adder 22a and input to the tube forming circuit 20, and the output data of the tube forming circuit 20 and the adder 22a are added. Added by the device 22b,
Further, the output data of the adder 22b is input to the subtractor 13 via the filter 30b. By doing so, the scattering of the air pressure wave at the end of the resonance tube on the mouthpiece side is simulated. Here, the filter 30b is inserted so that the signal circulating between the excitation circuit 10 and the tube forming circuit 20 does not become significantly large at a specific frequency.

Breath pressure data P corresponding to the blowing pressure is input to the subtracter 13 and feedback data via the filter 30b (this data is reflected at the end of the resonance tube and returned to the mouthpiece side) (Corresponding to the wave) is input. Then, the data corresponding to the air pressure in the gap between the mouthpiece and the lead is output from the subtractor 13 and input to the filter 30a. The filter 30a simulates the movement of the lead, and limits the band of the input signal and outputs it. This is because if you change the pressure on the leads,
Due to the inertia of the lead itself, the lead displacement is delayed. Furthermore, if the frequency of this pressure change is high, the reed will become unresponsive. The band limitation is performed in the filter 30a so as to simulate the followability of the lead according to such a pressure change. In addition, this filter
The 30a is configured to give an initial displacement to the lead according to the above-mentioned embouchure data E.

The output data P ₁ of the filter 30a is added to the adder 16
Thus, the embouchure data E is added as an offset, and the data P ₂ corresponding to the pressure actually applied to the lead is obtained. Then, this data P ₂ is stored in the ROM 11a.
To the non-linear function A stored in the ROM 11a.
By (see FIG. 10), the data is converted into a table corresponding to the data Y corresponding to the admittance with respect to the air flow in the gap between the mouthpiece and the lead. Subsequently, the data Y and the constant b are multiplied by the multiplier 31. Here, since this constant b is a value corresponding to the gap width between the mouthpiece and the lead, the data FL corresponding to the flow velocity of the air flow passing through the gap between the mouthpiece and the lead is obtained by this multiplication.

By the way, the flow velocity of the air flow in the gap between the mouthpiece and the lead changes depending on the air pressure, but becomes saturated at a certain velocity. FIG. 5 shows an example of the non-linear characteristic B showing the saturation characteristic of the flow velocity of the air flow. This saturation characteristic is stored in the ROM 11b as a table of the non-linear function B. Then, to the ROM 11b, the output of the subtracter 13, that is, the data corresponding to the air pressure in the gap between the mouthpiece and the lead described above is input, the table conversion is performed, and the data representing the air flow velocity in the saturated state is obtained. Is output. This data is multiplied by the above-mentioned data FL in the multiplier 32,
As a result, data f representing the true air velocity in the gap
Is required.

Next, the configuration of the noise generator 6 that generates the noise data N according to the data f will be described with reference to FIG. In this figure, 40 is a subtractor 40a, 40e and an adder 40b, 4e.
This is a second-order low-pass filter composed of 0g, coefficient multipliers 40c and 40f, and delay circuits 40d and 40h. The low-pass filter 40 filters the white noise signal WN supplied from the outside and outputs it as noise data N in order to simulate the turbulent flow phenomenon in the gap between the mouthpiece and the lead. This filtering approximates the spectral distribution of the white noise signal WN to the spectral distribution of turbulence, and this spectral distribution of turbulence is determined according to the Reynolds number R of the data f, as will be described later. Reference numeral 41 is a filter constant generation circuit composed of multipliers 41a and 41c and a calculator 41b, the details of which will be described later.

Here, the filtering of the white noise signal WN described above will be described. First, the Reynolds number R is a value representing the state of flow in a fluid, and it is generally known that when this value is 2000 (a dimensionless amount) or less, it becomes a laminar flow, and above this value, it becomes a turbulent flow. According to Kolmogorov's law, the larger the Reynolds number R, the more the spectral component of the turbulence extends to the low frequency region, and the energy of the direct current component is almost proportional to the Reynolds number R.
Therefore, the white noise signal WN with a uniform spectral distribution
By filtering according to the Reynolds number R, turbulent flow having a desired spectral distribution can be approximated.

Based on such a principle, in the low-pass filter 40, the coefficient α ₂ of the coefficient multiplier 40f is changed according to the Reynolds number R of the data f, and its frequency characteristic is as shown in FIG. In the figure, the horizontal axis is the log frequency and the vertical axis is d.
The B amplitude is taken, and the frequency characteristics in the cases where the coefficient α ₂ is 0.1, 0.03, 0.01, 0.003 and 0.001 are shown.

By the way, looking at the correlation between this frequency characteristic and the Reynolds number R, it can be seen that the coefficient α ₂ and R ^−1/2 are in a series relation. Therefore, in the filter constant generation circuit 41 described above,
First, the Reynolds number R is obtained by multiplying the data f and the constant C ₁ in the multiplier 41a. Where this constant
C ₁ is a value given by a / ν, a is a value representing the thickness and width of the flow, and ν is a kinematic viscosity coefficient. The Reynolds number R thus obtained is R ^−1/2 by the calculator 41b.
Is performed, and this is multiplied by the constant C ₂ in the multiplier 41c. The constant C ₂ is a value for associating both the coefficient α ₂ and R ^−1/2 . In this way, the coefficient data Dα ₂ output from the multiplier 41c is the low-pass filter described above.
The multiplication coefficient α ₂ of the coefficient multiplier 40f at 40 is set.
As a result, the cutoff frequency of the low-pass filter 40 is controlled according to the Reynolds number R of the data f that changes moment by moment, and noise data N that simulates turbulence is output.

Next, this noise data N is added to the adder 33 (see FIG. 4).
Is added to the data f, and as a result, the data FLN to which the data corresponding to the turbulence is added as an offset is output. Then, the multiplier 34 multiplies the data FLN by the constant Z. This constant Z is a value determined according to the diameter of the pipe near the reed mounting portion of the wind instrument,
It corresponds to the difficulty of passing the air flow, that is, the impedance to the air flow. By such multiplication,
Data corresponding to the air pressure in the pipe is obtained, and this data is input to the pipe forming circuit 20 via the adder 22a of the junction 22. Then, the output data of the tube forming circuit 20 is output to the junction 22, is input to the subtractor 13 via the filter 30b, and the same signal processing as described above is performed again.

Here, the configuration of the tube forming circuit 20 will be described with reference to FIG. In the figure, reference numerals 20a, ..., 20a denote delay circuits composed of shift registers, which simulate the propagation delay of the air pressure wave in the resonance tube. 20b, ..., 20b
Is a junction inserted between these delay circuits 20a. Reference numeral 20c is an inverter, which simulates reflection of an air pressure wave at the end of the resonance tube. 20d
Is a low pass filter (LPF) and 20e is a high pass filter (HPF). With such a configuration, the signal output from the delay circuit 20a at the final stage is divided into one that passes through the LPF 20d and is reflected at the tube end, and one that passes through the HPF 20e and is output as a musical sound output. Here, the HPF20e is inserted because the acoustic radiation impedance characteristic of a wind instrument is a high-pass characteristic. The delay amounts d _{1 to} dn, the junction coefficients k _{1 to} kn _-1, and the filter coefficients FCL and FCH shown in the figure are calculated based on the key code, the embouchure data E, and the breath pressure data P described above. The result is given and this operation is executed by the CPU2.

In the tone synthesis circuit 9 thus configured, the turbulent noise data N corresponding to the data f corresponding to the flow velocity of the air flow passing through the gap between the mouthpiece and the lead is added as an offset, so that the actual Signal processing is performed according to the noise generation mechanism in wind instruments. The musical tone signal output through such signal processing is supplied to the sound system 40 shown in FIG. 1, and the sound system 40 performs processing for causing the speaker SP to generate a musical tone. As a result, it is possible to faithfully reproduce noise effects such as subtone and breath leakage sound that become loud when the airflow velocity in the gap between the mouthpiece and the lead is saturated in a real wind instrument blowing. become.

In the above-described embodiment, the noise data N is added to the data f in the adder 33 as shown in FIG. 11 (a). As shown in (b), an adder 35 and a multiplier 36 may be provided, and 1 may be added to the noise data N before being multiplied by the data f. In this way, the data f is modulated with the noise data N.

[Advantages of the Invention] As described above, according to the present invention, the noise control means controls the characteristics of the noise signal in accordance with the excitation signal, so that the noise generation means generates a noise signal approximating the in-tube turbulence. However, since the noise superimposing means superimposes the noise signal on the circulating signal circulating through the loop means, there is an effect that musical tone synthesis is performed in accordance with the actual noise generating mechanism and the noise generated during the performance is faithfully reproduced. can get.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a musical sound synthesizing apparatus according to an embodiment of the present invention, and FIG. 2 is an external view showing an example of an operator 1 in the same embodiment. FIG. 3 is a block diagram showing the configuration of the information conversion circuit in the same embodiment, FIG. 4 is a block diagram showing the configuration of the tone synthesis circuit 9, and FIG. 5 is the ROM 11b.
6 is a block diagram showing the configuration of the noise generator 6, FIG. 7 is a diagram showing the frequency characteristics of the low-pass filter 40, and FIG. 8 is a tube forming circuit 20. FIG. 9 is a block diagram showing the configuration of a conventional tone synthesizer, FIG. 10 is a diagram explaining the non-linear function A in FIGS. 4 and 9, and FIG. 11 is a data f. It is a block diagram which shows an example which gives noise data N. 5 ... Microcomputer, 6 ... Noise generator, 7 ... Lead section, 8 ... Tube section, 40 ... Low-pass filter, 41 ... Filter constant generation circuit.

Claims (2)

(57) [Claims] 1. An excitation means for generating an excitation signal, and a loop means for delaying at least a predetermined time of its own input signal and repeatedly circulating the excitation signal,
In a musical tone synthesizer in which the circulating signal of the loop means is used as a musical tone signal, a noise generating means for generating a noise signal and a characteristic of the noise signal generated by the noise generating means are controlled according to the excitation signal. Noise excitation means, and noise superposition means for superimposing the noise signal generated by the noise generation means on a circulating signal circulating in the loop means and outputting the superposed signal to the loop means, wherein the excitation signal A tone synthesizer which superimposes a noise signal having a characteristic according to the above on a circulating signal circulating through the loop means. 2. The noise control means controls the characteristic of the noise signal generated by the noise generating means in accordance with the excitation signal and the circulating signal circulating in the loop means. The musical sound synthesizer according to item 1.