JP2727881B2 - Music synthesizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tone synthesizer suitable for use in the synthesis of natural musical instrument sounds.

[0002]

2. Description of the Related Art A natural musical instrument has a resonator and an excitation mechanism for exciting vibrations in the resonator, and a musical tone is generated by an interaction between these resonators. For example, a wind instrument has a resonance tube as a resonator and a mouthpiece and a lead as an excitation mechanism. In such a configuration, when the player blows into the mouthpiece, vibration is excited in the reed attached to the mouthpiece. This vibration is reciprocated as an air pressure wave in the resonance tube, and is emitted as a musical tone. Also, the vibration of the lead is affected by the air pressure wave returned from the resonance tube to the mouthpiece side. By performing the interaction between the resonance tube and the lead in this way, a musical tone unique to the wind instrument is generated.

As a tone synthesizer which simulates the sounding mechanism of such a natural musical instrument faithfully, there is a non-linear feedback tone synthesizer. This musical tone synthesizer has a basic configuration including a loop circuit composed of a nonlinear element simulating the behavior of an excitation mechanism of a natural musical instrument and a delay circuit simulating a resonator. When a signal including many frequency components such as an impulse is input to such a loop circuit, the signal repeatedly circulates in the loop. Then, a component of a specific frequency is selected and circulation is maintained. By causing the loop circuit to be in a resonance state, a tone signal is generated.

Here, the loop circuit includes a resonance mode (fundamental mode) at a resonance frequency corresponding to a delay time in which a signal circulates and loops in the loop, and a resonance mode (overtone) at a higher-order resonance frequency that is an integral multiple thereof. Mode). But,
Which resonance mode the loop circuit is in depends on factors other than the delay element in the loop circuit, such as the operating point of the non-linear element, and sometimes the resonance mode is unintended and the desired tone signal cannot be obtained. There is.

Therefore, conventionally, in order to cause resonance at a desired resonance frequency, a frequency selecting means such as a filter has been inserted in the loop circuit. According to such a configuration, only a signal corresponding to a pitch to be generated is circulated in the loop circuit by adjusting a coefficient for filter operation or the like, and a tone signal having a desired pitch can be obtained.

[0006]

However, even if parameters such as coefficients for filter operation are set appropriately, it may be difficult to prevent resonance in an undesirable mode depending on the pitch, and accurate sound generation may occur. There is a problem that the range of pitches that can be used is narrowed. Also,
If the cutoff frequency of the filter in the loop circuit is reduced to promote resonance in the low-order mode, the high-order harmonics contained in the tones to be generated are extremely reduced, and the sound quality becomes unfavorable. In addition, there is a resonance mode that is difficult to select among resonance modes of the loop circuit, and there is a problem that it is difficult to generate sound when a desired pitch corresponds to such a resonance mode.

[0007] The present invention has been made in view of the above circumstances, and can expand the range of pitches that can be pronounced.
It is an object of the present invention to provide a tone synthesizer capable of synthesizing a tone having a desired pitch without sacrificing sound quality.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a closed loop means having at least a delay means connected in a closed loop, and a drive signal.
And the drive signal is input to the closed loop means.
A dynamic signal generating means, and a frequency of a signal circulating through the closed loop.
Detecting the number, based on the musical sound height to be generated with the frequency
Characteristics of the driving signal generated by the driving signal generating means.
And control means for controlling

[0009]

According to the above arrangement, the control means controls the closing loop.
The frequency of the signal circulating through the loop is detected and the detected frequency
Based on the number and the pitch of the musical tone to be generated
The characteristics of the input drive signal are controlled. This allows
The resonance mode of the closed loop means is controlled according to the measured pitch and the target pitch .

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a synthesizer 1 of a musical sound synthesizer according to an embodiment of the present invention . This synthesis unit 1
Is composed of an excitation circuit 10 simulating a mouthpiece of a wind instrument, a waveguide network (bidirectional transmission circuit) 20 simulating a resonance tube of the wind instrument, and a junction 30 connecting these components to each other.

The junction 30 includes adders 31 and 3
Consists of two. Adder 31 is web guide network 2
0 and each output signal of the excitation circuit 10 are added, and the addition result is supplied to an input terminal of the waveguide network 20. The output signal of the adder 31 is supplied to a sound system (not shown) as a tone signal MS. On the other hand, the adder 32 adds the output signals of the web guide network 20 and the adder 31 and outputs the addition result to the excitation circuit 1.
0 to the low-pass filter 11.

The waveguide network 20 is composed of a linear circuit such as a delay circuit and a low-pass filter (both not shown). The waveguide network 20 performs delay processing, filtering processing, and the like on a signal supplied from the excitation circuit 10 via the adder 31, and returns the result to the excitation circuit 10 via the adder 32. As the delay circuit in the waveguide, one having a configuration capable of adjusting the delay time is employed. This type of delay circuit can be composed of, for example, a shift register and a selector for selecting one of the stage outputs of the shift register. It is also possible to configure this kind of delay circuit using a RAM (random access memory). The delay time of the delay circuit is set such that the resonance frequency determined by the total delay time of the closed loop including the waveguide network 20 and the excitation circuit 10 becomes a frequency corresponding to a desired pitch.

Next, the configuration of the excitation circuit 10 will be described. The signal returned from the waveguide network 20 via the adder 32 is input to the low-pass filter 11.
This signal corresponds to an air pressure wave returned from the resonance tube side into the mouthpiece. The low-pass filter 11 is inserted in order to prevent occurrence of abnormal oscillation in each closed loop (for example, a closed loop including the excitation circuit 10, the adder 31, the adder 32, and the excitation circuit 10) formed in the synthesis unit 1. And suppresses passage of a signal in a high frequency region that may cause abnormal oscillation. The adder 12 adds the signal passed through the low-pass filter 11 and the pressure signal P corresponding to the blowing pressure, and outputs a signal corresponding to the air pressure in the mouthpiece. The output signal of the adder 12 is the filter 1
3 and a non-linear conversion circuit 14.

The filter 13 is a filter which simulates a response characteristic of a lead to a pressure change in the mouthpiece, and for example, a low-pass filter is used. The adder 15 adds the signal passed through the filter 13 and an embouchure signal E corresponding to the pressure at which the player holds the mouthpiece (this pressure is called embouchure). Here, the embouchure signal E is also used as a parameter for controlling the cutoff frequency of the filter 13. This takes into account that the response characteristics of the lead are also affected by the embouchure. The signal output from the adder 15 is
It corresponds to the pressure of the airflow that is going to pass through the gap between the lead and the mouthpiece. The non-linear conversion circuit 16 has input / output transmission characteristics that simulate the elastic characteristics of the leads, and is constituted by, for example, a ROM (Read Only Memory). As a result of the output signal of the adder 15 being input to the nonlinear conversion circuit 16, a signal corresponding to the cross-sectional area of the gap between the lead and the mouthpiece is output from the nonlinear conversion circuit 16. The multiplier 17 adds a predetermined coefficient b to the output signal of the nonlinear conversion circuit 16.
And output. On the other hand, the nonlinear conversion circuit 14 has input / output transfer characteristics that simulate the saturation of the flow velocity of the airflow passing through the gap between the lead and the mouthpiece,
For example, it is constituted by a ROM. A signal output from the adder 12 and corresponding to a pressure change in the mouthpiece is converted by the non-linear conversion circuit 14 so that a saturation characteristic is provided. The multiplier 18 multiplies the output signal of the multiplier 17 by the output signal of the non-linear conversion circuit 14, and outputs a signal corresponding to the volume flow velocity of the airflow passing through the gap between the lead and the mouthpiece. This output signal is multiplied by a signal Z corresponding to the impedance of the airflow of the mouthpiece (difficulty in passing the airflow) by the multiplier 19, and a signal corresponding to a pressure change in the mouthpiece is output. The adder 40e applies the output signal of the multiplier 19 to
The forced drive signals ext output from the forced drive circuits 40 and 40a shown in FIG . 2 or FIG. 3 are added, and the addition result is supplied to the adder 31.

Here, the forced drive signal ext is generated.
Refer to FIG. 2 for the basic configuration and the operation thereof.
Will be explained. As shown in FIG. 2, the forced drive circuit 40
Address generation circuit 41, envelope read counter 4
2, drive waveform memory 43, envelope waveform memory 44
And a multiplier 45. At the start of sound generation, a key-on signal KON for instructing sound generation and a key code KC for designating a pitch to be sounded are supplied to the forced drive circuit 40. The address generation circuit 41 is reset by the key-on signal KON, and increases the drive waveform read address AD at a speed corresponding to the key code KC. Drive waveform memory 4
Numeral 3 stores, at each address, a waveform value at each time point of the drive waveform over a predetermined period (for example, one cycle), and outputs a waveform value specified by the drive waveform address AD. The envelope waveform memory 44 stores each key code KC
Each waveform value of an envelope waveform suitable for each tone generation is stored for each tone range including each or a plurality of key codes KC. The envelope read counter 42 stores the envelope waveform read address EA in the envelope waveform memory 44.
Supply D. When the key-on signal KON is generated, the envelope waveform read address EAD is initialized to the start address of the envelope waveform corresponding to the key code KC, and thereafter, is sequentially incremented with time. The multiplier 45 multiplies the driving waveform read from the driving waveform memory 43 by the envelope waveform read from the envelope waveform memory 44, and supplies the resultant to the adder 40e (FIG. 1) as a forced driving signal ext.

According to the above configuration, the closed loop including the excitation circuit 10 and the waveguide network 20 is brought into a resonance state in the synthesizing section 1, whereby the tone signal MS is generated.
Is generated. Here, when the compulsory drive signal ext is not generated, it is determined whether the combining unit 1 performs the resonance operation in the resonance mode of the fundamental mode or another higher-order mode. Alternatively, it depends on the operating point of each nonlinear conversion circuit. In addition, resonance may not be easily started. However, according to the sounding instruction, it has a frequency corresponding to a desired key code KC,
Further, a forced drive signal ext having an envelope corresponding to the key code KC is generated and circulates in the closed loop. As a result, the resonance operation at the frequency corresponding to the key code KC is forcibly started, and the tone signal M having a desired pitch is started.
S is obtained.

Next, referring to FIG. 3, the forced driving according to the present invention will be described.
The configuration and operation of the dynamic circuit will be described. 3, a zero-phase detection circuit 51 detects that the phase angle of the tone signal MS output from the synthesis unit 1 (FIG. 1) becomes zero, and outputs a detection signal. The AND gate 54 supplies a logical product of the detection signal and the key-on signal to the address generation circuit 41 as a reset signal. The volume detection circuit 52 detects the volume of the tone signal MS. The mode determination circuit 53 determines whether or not the synthesizing unit 1 resonates in an appropriate mode corresponding to the key code KC based on the tone signal MS, and outputs an error signal if the mode is not appropriate. The input amount control circuit 55 generates an envelope waveform corresponding to the key code KC. This envelope waveform is shown in FIG.
Similarly to the forced drive circuit 40 , the drive waveform read from the drive waveform memory 43 is multiplied by the multiplier 45.
Further, the intensity of the envelope waveform output from the input amount control circuit 55 is controlled based on the volume value of the tone signal MS detected by the volume detection circuit 52 and the error signal output from the mode determination circuit 53. When the resonance in the mode corresponding to the key code KC is not performed and the error signal is output or when the sound is not generated at an appropriate volume, the amplitude of the envelope waveform is increased by the input amount control circuit 55. .

FIG. 4 shows a configuration example of the mode determination circuit 53. In FIG. 4, reference numerals 60-1 to 60-n denote bandpass filters having different passband center frequencies. The envelope follower circuits 70-1 to 70-n receive the respective signals that have passed through the band-pass filters 60-1 to 60-n, and output envelope waveforms enclosing the respective peak values in the input signals. The maximum value judging circuit 81 judges which one of the envelope waveforms output by the envelope follower circuits 70-1 to 70-n has the largest waveform value, and detects the resonance frequency of the synthesizing unit 1 based on the judgment result. .
The comparing circuit 82 compares the pitch information PITCH representing the frequency corresponding to the key code KC with the resonance frequency of the synthesizing unit 1 detected by the maximum value judging circuit 81, and outputs an error signal when the two do not match. I do.

According to the above configuration, when the resonance operation is performed in the synthesizing unit 1 and the tone signal MS is output, each time the phase angle of the tone signal MS becomes zero, the address generation circuit 4
1 is reset, a drive waveform having a frequency corresponding to a desired pitch is read from the drive waveform memory 43, and supplied to the synthesizing unit 1 as a forced drive signal ext. The frequency of the tone signal MS output from the synthesizing unit 1 is the key code KC
, An error signal is generated, and the magnitude of the envelope of the forced drive signal ext is increased. Therefore, sound generation at a desired pitch can be performed stably.

In each of the above embodiments, the forced drive signal having a frequency corresponding to a desired pitch is supplied to the synthesizing section. However, the frequency of the forced drive signal is slightly shifted from the resonance frequency of the synthesizing section. Is also good. By doing so, a musical sound having a beat can be synthesized. Alternatively, a low frequency signal may be superimposed on the forced drive signal to synthesize a musical tone having a complicated tone. Further, the frequency of the forced drive signal may be changed to change the resonance mode in real time.

[0021]

As described above, according to the present invention,
A closed loop means having at least a delay means connected in a closed loop , a drive signal being generated, and the drive signal being transmitted to the closed loop means.
Drive signal generating means for inputting a, to circulate the closed loop
The driving signal generated by the driving signal generating means is detected based on the frequency and the pitch of a musical tone to be generated.
Since the control means for controlling the characteristics of the dynamic signal is provided, the range of pitches that can be generated can be widened, and the sound generation at the desired pitch can be performed accurately and without sacrificing the sound quality.
The effect that it can be performed stably is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a synthesizing unit 1 of a musical sound synthesizing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a basic configuration of a forced drive circuit.

FIG. 3 is a block diagram showing a configuration of a compulsory driving circuit 40a of the musical sound synthesizer according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration example of a mode determination circuit 53 illustrated in FIG . 3 ;

[Explanation of symbols]

10 Excitation circuit, 30 Waveguide network, 40, 40a Forced drive circuit

Claims (1)

(57) [Claims] At least a delay means is connected in a closed loop.
A closed loop means for generating a drive signal; and inputting the drive signal to the closed loop means.
A driving signal generating means for detecting the frequency of a signal circulating through the closed loop;
The drive signal is generated based on the number and the pitch of the musical tone to be generated.
Control means for controlling the characteristics of the drive signal generated by the generating means .