JPH05249976A - Forming device for musical sound waveform signal - Google Patents

Abstract

PURPOSE:To suppress unnaturalness of tone quality and generation of noise and form a natural musical sound waveform signal with less noise by outputting an output signal after non-linear conversion to be outputted from a non-linear converting means onto a circulating signal path after filtering it. CONSTITUTION:Play information such as sound production instructing signal, tone information and touch information is outputted from a play operating element according to the operation of a keyboard by a player. Tone information is outputted from a setting operating element. A parameter generating part outputs various parameters according to the information. The bow speed E inputted to an exciting part 14 of these parameters is inputted to a NL converting part 22 through an adder 21 and non-linearly converted. The NLO of the output signal after nonlinear conversion is filtered with a filter 23, and, for example, subjected to the processing for interrupting a high frequency component. The output of the filter 23 is outputted onto a loop circuit through a multiplier and the adder with the output of the exciting part 14 being OUT, and circulated on the loop circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone waveform signal forming apparatus used for an electronic musical instrument or the like, and more particularly to a musical tone waveform signal forming apparatus having a circulating signal path for circulating a waveform signal to form a desired musical tone waveform signal. ..

[0002]

2. Description of the Related Art Conventionally, there has been known a device for forming a tone waveform signal by using a physical model simulating a natural musical instrument. For example, in Japanese Patent Laid-Open No. 3-58095,
A musical tone signal forming apparatus simulating a stringed instrument such as a violin or a viola is disclosed.

In this system, first and second signal delay means are provided in series in a circulating signal path for circulating a waveform signal, while an external activation control signal (a signal corresponding to the bow speed of a stringed instrument) is supplied. The waveform signals on the circulating signal paths between the first and second signal delay means are combined with each other, subjected to non-linear conversion, and output again on the circulating signal path between the first and second signal delay means. is there.

[0004]

By the way, in the above-mentioned prior art, the signal injected into the circulating signal path is non-linearly converted by the non-linear conversion means. This non-linear transformation is such that when a bow is rubbed against a string, when the bow speed is small, the frictional force between the bow and the string is mainly controlled by the static friction coefficient, and the string speed becomes almost the same as the bow speed. This is a conversion performed in order to simulate a phenomenon in which the frictional force is mainly governed by the dynamic friction coefficient and the chord velocity becomes lower than the bow velocity when the bow velocity becomes large. Therefore, the input / output characteristic of the non-linear conversion means is an output (string velocity) that is almost proportional when the input (bow velocity) is in a certain range, and falls to a low value output at that position when the input exceeds the limit value. It has such characteristics. In other words, it has a characteristic that it becomes discontinuous at a predetermined limit value.

Since the waveform signal nonlinearly converted by the nonlinear conversion means having such a characteristic is injected into the circulation signal path, the tone waveform signal obtained from this circulation signal path also has a sawtooth waveform with many high frequency components. There are problems that the waveform becomes non-linear, the sound quality of the finally emitted musical sound becomes unnatural, and it often causes aliasing noise.

In view of the problems in the above-described conventional example, the present invention provides a tone waveform signal forming apparatus having a circulation signal path for circulating a waveform signal to form a desired tone waveform signal, and a nonlinear waveform in the circulation signal path. It is an object of the present invention to suppress the unnaturalness of sound quality and the generation of noise that have been caused by injecting into, and to form a musical tone waveform signal that is natural and has little noise.

[0007]

In order to achieve this object, a musical tone waveform signal forming apparatus according to the present invention has a circulating signal path for circulating a waveform signal and one or more circulating signal paths provided in the circulating signal path. A signal delay means, an input means for inputting a drive signal from the outside, a waveform signal on the circulation signal path, a combination of the drive signal and the waveform signal, and an output of a combined signal; A non-linear conversion means for performing a non-linear conversion on the combined signal output from the non-linear conversion means, and a filtering means for filtering the non-linear conversion output signal output from the non-linear conversion means, and outputting to the circulating signal path. Characterize.

As the filtering means, for example, a low-pass filter having a predetermined cutoff frequency and blocking (or attenuating) high frequency components may be used. Further, the filter is a FIR (Finite Impu)
lse Response: Finite impulse response) or IIR (Infinite Impulse Response)
sponse: infinite impulse response). The characteristic of the filtering means may be determined in association with the control in the non-linear conversion means. That is, the characteristic of the filtering means may be determined according to the input / output characteristic of the non-linear conversion. Further, the characteristics of the filtering means may be determined according to a drive signal from the outside.

If a hysteresis characteristic is added to the non-linear conversion, a more natural sound quality can be obtained. In order to provide the hysteresis characteristic, it is preferable that the output obtained by filtering the output signal after the non-linear conversion by the filtering means is fed back (positive feedback) to the input side of the non-linear conversion means. When a feedback structure for providing such a hysteresis characteristic is provided, the characteristics of the filtering means are determined so that abnormal oscillation does not occur in this feedback structure. Further, in order to add a hysteresis characteristic to the non-linear conversion, the output signal after the non-linear conversion may be fed back via another filtering means different from the filtering means.

[0010]

The non-linear conversion output signal output from the non-linear conversion means is not directly output on the circulation signal path, but is output on the circulation signal path after filtering the non-linear conversion output signal. Therefore, for example, if a high frequency component is removed from the non-linearly converted waveform signal and is output on the circulating signal path, a natural tone waveform signal with less noise can be formed.

If the characteristics of the filtering means are linked to the control in the non-linear converting means, fine tone color control is possible. Moreover, if a hysteresis characteristic is added to the non-linear conversion, a more natural sound quality can be obtained.

[0012]

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

FIG. 1 shows a block configuration of an electronic musical instrument to which a musical tone waveform signal forming apparatus according to an embodiment of the present invention is applied. In this embodiment, the present invention is applied to a physical model simulating a stringed instrument.

The electronic musical instrument of this embodiment has a performance operator 1,
Setting operator 2, parameter generator 3, delay circuits 5, 6,
Multipliers 7, 8, filters 9, 10, adders 11, 12,
The adder 13, the excitation unit 14, and the multiplier 15 are provided. Delay circuits 5 and 6, multipliers 7 and 8, filters 9 and 1
0, the adders 11 and 12, the adder 13, the excitation unit 14, and the multiplier 15 form a tone waveform signal forming apparatus.

The performance operator 1 is a keyboard having a plurality of keys corresponding to a scale, and outputs performance information such as a sounding instruction signal, pitch information and touch information in response to the player's operation of the keyboard. Instead of the keyboard, another operating device may be used, for example, an operating device that can imitate the operation of rubbing the bow and strings of a stringed instrument. The setting operator 2 includes a switch such as a tone color selection switch and outputs tone color information representing the selected tone color. The parameter generator 3 inputs performance information and tone color information, and generates and outputs various parameters that define the tone waveform signal to be generated in accordance with these information.

The closed loop circuit 4 is a circulating signal path that circulates a tone waveform signal corresponding to the strings of a stringed instrument, and includes delay circuits 5 and 6 and multipliers 7 and 8 connected in series as shown in the figure.
It is composed of filters 9 and 10 and adders 11 and 12.

The delay circuits 5 and 6 are variably controlled in delay time according to the parameters D1 and D2 input to them. The loop circuit 4 corresponds to the string of the stringed instrument, and the delay time in the delay circuits 5 and 6 corresponds to the length of the string. Therefore, by controlling each delay time in the delay circuits 5 and 6 by the parameters D1 and D2,
The pitch of the generated musical sound is controlled. Parameter generator 3
Determines these delay times D1 and D2 in accordance with the pitch information input from the performance operator 1, and outputs them to the delay circuits 5 and 6.

Filters (low-pass filters) 9, 10
The filter characteristics are variably controlled in accordance with the parameters F1 and F2 input to each. By changing the filter characteristics of the filters 9 and 10, it is possible to simulate the vibration characteristics of various strings, thereby changing the tone color of the musical tone. The parameter generator 3
These filter characteristic parameters F1 and F2 are determined according to the touch information input from the performance operator 1 and the tone color information input from the setting operator 2, and output to the filters 9 and 10.

The multipliers 7 and 8 shift the phase of the waveform signal circulating in the loop circuit 4 by π by multiplying it by "-1". The multipliers 7 and 8 realize the termination condition at both fixed ends of the string.

The waveform signals on the loop circuit 4 on the output sides of the filters 9 and 10 are input to the adder 13 and added. The addition result is input to the excitation unit 14 as the input signal IN. This simulates that the contact part between the bow and the string is displaced by the vibration wave traveling on the string.

The excitation unit 14 simulates the displacement state of the string when the bow is rubbed on the string. The exciting unit 14 has a bow speed signal E corresponding to the moving speed (bow speed) of the bow in the stringed instrument, a bow pressure signal TBLC indicating the pressure applied to the strings from the bow during the bow movement, and feedback inside the exciting unit 14. The feedback gain FG that defines the gain of the loop (described later with reference to FIG. 2) and the input signal IN from the adder 13 that represents the vibration wave currently traveling on the string are input. Then, an output signal OUT representing the displacement state of the string when the bow is rubbed against the string under the conditions of the bow speed E and the bow pressure TBLC is output. In addition, the excitation unit 14 receives the input signal IN,
It also simulates how an oscillating wave already traveling on the string affects the displacement state of the string.

Bow speed E and bow pressure TBL input to the excitation unit 14
The parameter generator 3 generates C and the feedback gain FG. In particular, the bow speed E is based on the touch information input from the performance operator 1 and the bow pressure TBLC is based on the touch information input from the performance operator 1 and the tone color information input from the setting operator 2. The FG is determined and output in accordance with the touch information input from the performance operator 1 and the tone color information input from the setting operator 2. In addition, these parameters are set by the performance operator 1.
Is output while the tone generation instruction signal is output from.

The output signal OUT, which indicates the displacement state of the string output from the excitation unit 14, is input to the multiplier 15, and the constant 1 /
It is multiplied by 2. The multiplication result is output to the loop circuit 4 via the adders 11 and 12 provided in the loop circuit 4.

The output of the tone waveform signal from the loop circuit 4 is taken from the output side of the adder 11. The output of the tone waveform signal is input to a sound system (not shown), so that sound is actually emitted. The output of the tone waveform signal may be taken from any position of the loop circuit 4. Alternatively, the outputs may be taken out from a plurality of locations, combined, and used. Furthermore, for the output signal taken out,
It is also possible to perform post-processing such as adding a predetermined formant and input the sound system.

FIG. 2 shows a detailed block configuration of the excitation unit 14. The excitation unit 14 includes an adder 21, a non-linear (NL) conversion unit 22, a filter (low-pass filter) 23, a multiplier 24, and a filter parameter supply unit 25.

The adder 21 adds the bow speed E and the input signal IN input to the exciter 14 and the output of the multiplier 24. The output of the adder 21 is input to the NL conversion unit 22 as an input signal NLI. The NL converter 22 receives the input signal NL
A non-linearly converted output NLO is output by simulating the displacement state of the string due to the movement of the bow by performing a non-linear conversion of I. The input / output characteristics of the NL converter 22 are controlled to be changed according to the bow pressure TBLC. NL converter 22
The input / output characteristics of will be described later in detail.

Non-linearly converted output N from the NL converter 22
LO is input to the filter 23. The filter 23 is a low-pass filter having a predetermined cutoff frequency, and thereby cuts off (or attenuates) high frequency components in the output NLO after nonlinear conversion. This filter 23
The signal passed through is output as the output signal OUT of the excitation unit 14.

The input / output characteristics of the filter 23 are changed and controlled in accordance with the filter parameter supplied from the filter parameter supply section 25. The filter parameter supply unit 25 inputs the bow pressure TBLC and generates and outputs a filter parameter according to this value. Therefore, the bow pressure T
The input / output characteristics of the filter 23 are determined according to BLC,
As a result, it is possible to realize a change in timbre according to the bow pressure TBLC. As described above, the input / output characteristics of the NL converter 22 are also changed and controlled according to the bow pressure TBLC, and as a result,
NL is linked with the input / output characteristic change control of the NL converter 22.
The input / output characteristics of the conversion unit 22 are changed and controlled.
Note that the filter parameter supply unit 25 may further generate and output a filter parameter according to the bow speed E. Further, the filter parameters may be changed according to the pitch.

The output of the filter 23 is output as the output signal OUT, and is also added via the multiplier 24 to the adder 2
It is fed back to 1. By this feedback, the hysteresis characteristic is given to the non-linear conversion. By giving such a hysteresis characteristic, the relationship between the bow and the string of the stringed instrument whose friction coefficient changes according to the bow speed is better simulated, and the finally obtained musical sound is similar to that of the stringed musical instrument. Become. The multiplier 24 has a filter 23.
The output of is multiplied by the feedback gain FG,
As a result, the width of hysteresis is changed and controlled.

FIG. 3 is a graph showing an example of the input / output characteristics of the NL conversion section 22 described above. The horizontal axis represents the input NLI and the vertical axis represents the output NLO. The input / output characteristics of the NL converter 22 are
It is changed according to the bow pressure TBLC. Here, bow pressure TB
When LC is small, it shows a gentle input / output characteristic as shown by the solid line, and as the bow pressure TBLC gradually increases, it shows steeper input / output characteristics from the broken line to the one-dot chain line and two-dot chain line.

With the NL conversion of such characteristics, when the bow is rubbed against the string, when the bow speed is small, the frictional force between the bow and the string is mainly controlled by the static friction coefficient, and the string speed is the bow speed. Simulates that the frictional force is mainly governed by the dynamic friction coefficient and the chord velocity becomes slower than the bow velocity when the bow velocity increases, although it is almost the same as the above (the characteristics are set so that the directions are opposite). I am

FIG. 4 is a graph showing an example of the input / output characteristics of the filter 23. The horizontal axis represents the input value to the filter 23, and the vertical axis represents the output value. The input / output characteristics of the filter 23 are changed according to the bow pressure TBLC. Here, when the bow pressure TBLC is small, a gentle input / output characteristic like a solid line is shown, and as the bow pressure TBLC is gradually increased, a steeper input / output characteristic from a broken line to a one-dot chain line or a two-dot chain line is shown. It has become.

As can be seen from FIGS. 3 and 4, and as described above, the input / output characteristic of the NL converter 22 and the input / output characteristic of the filter 23 are interlocked with each other, and the bow pressure TBL.
Change control is performed according to C. As a result, when the bow pressure is small, the input / output characteristic of the NL conversion unit 22 has relatively few high frequency components as shown by the solid line in FIG. 3, so the input / output characteristic of the filter 23 is also comparatively gentle, and conversely When is large, the input / output characteristic of the NL conversion unit 22 has many high frequency components as indicated by the chain double-dashed line in FIG. 3, so that the input / output characteristic of the filter 23 is steep and control can be performed to cut off high frequency components. Becomes Also, intentionally, when the bow pressure is small, the input / output characteristic of the filter 23 is made steep to cut off high frequency components, and when the bow pressure is large, the input / output characteristic of the filter 23 is made smooth and a high frequency component is output. Such control can also be performed. That is, various tone color change controls can be realized according to the bow pressure.

Next, the operation of the electronic musical instrument of the embodiment constructed as above will be described.

First, performance information such as a tone generation instruction signal, pitch information, and touch information is output from the performance operator 1 in response to the player's operation of the keyboard. The tone color information is output from the setting operator 2. The parameter generator 3 outputs various parameters according to the information. Among these parameters, the bow speed E input to the excitation unit 14 is input to the NL conversion unit 22 via the adder 21 and is nonlinearly converted. The output signal NLO after the non-linear conversion is filtered by the filter 23, and is subjected to processing such as blocking high frequency components. The output of the filter 23 is used as the output OUT of the excitation unit 14, and the multiplier 15 and the adder 1
It is output to the loop circuit 4 via 1 and 12.

The signal output on the loop circuit 4 circulates on the loop circuit 4. At this time, the pitch of the waveform signal circulating on the loop circuit 4 is determined by the delay times (parameters D1 and D2) of the delay circuits 5 and 6. Filters 9 and 10 are provided in the loop circuit 4, and frequency characteristics according to the characteristics of the strings are added to the circulating waveform signal. The circulating waveform signal is input to the adder 21 of the excitation unit 14 via the adder 13 and added with the bow speed E to obtain N.
Since it is input to the L conversion unit 22, it is simulated that the contact portion between the bow and the string is displaced by the vibration wave traveling on the string. Further, the output of the excitation unit 14 is fed back to the adder 21 via the multiplier 24, thereby giving a hysteresis characteristic to the input / output characteristic of the nonlinear conversion.
The tone waveform signal circulating in the loop circuit 4 is taken out from the output side of the adder 11 and input to the sound system in the subsequent stage.

FIG. 5 shows a circuit example of the NL converter 22.
The NL conversion unit 22 shown in FIG.
, 31-2, ..., 31-n, n multipliers 32-1,
32-2, ..., 32-n, a coefficient generator 33, and an adder 34. n number of conversion tables 31-1, 3
, 1-2, 31-n output respective values according to the input signal NLI that has been input. These outputs are output by the coefficient k in multipliers 32-1, 32-2, ..., 32-n, respectively.
1, k2, ..., kn. These coefficients k1,
The coefficient generator 33 outputs k2, ..., kn based on the bow pressure TBLC. Multipliers 32-1, 32-2, ..., 32
The output of -n is added by the adder 34.

Conversion tables 31-1, 31-2, ..., 3
By appropriately selecting the respective contents of 1-n and the coefficients k1, k2, ..., kn generated in the coefficient generator,
The input / output characteristics as shown in FIG. 3 can be realized.

FIG. 6 shows another circuit example of the NL converter 22. The NL conversion unit 22 in this figure includes a divider 41, a conversion table 42, a multiplier 43, and a coefficient generation unit 44. The coefficient generation unit 44 outputs coefficients that are the divisor of the divider 41 and the multiplier of the multiplier 43, based on the bow pressure TBLC. The conversion table 42 realizes the input / output characteristics shown in FIG. 3, for example. The input signal NLI is divided by the coefficient output from the coefficient generator 44 in the divider 41, nonlinearly converted in the conversion table 42, and the coefficient generator 4 in the multiplier 43.
It is multiplied by the coefficient output from the signal No. 4 and output as the output signal NLO. Therefore, the input / output characteristic of the NL converter 22 is similar to the input / output characteristic of the conversion table 42. The characteristics of the conversion table 42 may be directly changed and controlled by the bow pressure TBLC as indicated by the dotted line 45.

According to the above embodiment, the non-linearly converted output signal NLO is injected into the loop circuit 4 via the filter 23. Therefore, for example, if a low-pass filter that blocks a predetermined high frequency component is used as the filter 23,
Since the high frequency component is removed from the output signal NLO after the non-linear conversion, the tone waveform signal extracted from the loop circuit 4 is natural and does not include folding noise. In addition, the filter 23
Since the output of is fed back to the adder 21,
It is possible to add hysteresis characteristics to non-linear conversion,
A more natural tone waveform signal can be formed.

In the above embodiment, an example in which the present invention is applied to a physical model simulating a stringed instrument has been described, but the present invention is not limited to a model of a stringed instrument. Further, in the above embodiment, the example in which the excitation unit is outside the loop circuit has been described.
The excitation unit may form part of the loop circuit.

[0042]

As described above, according to the present invention, in the tone waveform forming apparatus having the circulating signal path for circulating the waveform signal to form the desired tone waveform signal,
Since the waveform signal after the non-linear conversion is filtered and then injected into the circulation signal path, it is possible to suppress the unnaturalness of sound quality and the generation of noise, and to form a musical tone waveform signal which is natural and has little noise.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an electronic musical instrument to which a musical tone waveform signal forming apparatus according to an embodiment of the present invention is applied.

FIG. 2 is a detailed block configuration diagram of an excitation unit.

FIG. 3 is a graph showing an example of input / output characteristics of a non-linear conversion unit.

FIG. 4 is a graph showing an example of input / output characteristics of a filter.

FIG. 5 is a circuit example (1) of a non-linear conversion unit.

FIG. 6 is a circuit example of a non-linear conversion unit (part 2).

[Explanation of symbols]

1 ... Performance operator, 2 ... Setting operator, 3 ... Parameter generator, 5, 6 ... Delay circuit, 7, 8 ... Multiplier, 9, 10 ... Filter, 11, 12 ... Adder, 13 ... Adder, 14 ... Excitation unit, 15 ... Multiplier, 21 ... Adder, 22 ... Non-linear (N
L) conversion unit, 23 ... filter, 24 ... multiplier, 25 ... filter parameter supply unit.

Claims (1)

[Claims] 1. A circulating signal path for circulating a waveform signal, one or more signal delay means provided in the circulating signal path, a drive signal from the outside, and a waveform signal on the circulating signal path. Input means for synthesizing the drive signal and the waveform signal to output a composite signal, a non-linear converting means for performing non-linear conversion on the composite signal output from the input means, and the non-linear converting means. And a filtering means for filtering the output signal after the non-linear conversion and outputting it on the circulating signal path.