JP3296156B2 - Resonant sound adding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance sound adding apparatus for emphasizing a specific frequency and imparting a characteristic to a tone signal, and more particularly to preventing abnormal resonance of the resonance sound adding apparatus.

[0002]

2. Description of the Related Art A resonance portion of a natural instrument such as a guitar body or a piano soundboard has a frequency characteristic that is not flat, and a tone unique to the instrument can be produced by emphasizing a specific frequency component of a musical tone. . Various resonance effectors which simulate the resonance section of such a natural musical instrument have been proposed.

FIGS. 8 and 9 are block diagrams of a conventional resonance effector of this type. The device shown in FIG. 8 is a resonance effector in which a plurality of comb filters are connected in parallel. The comb filter inputs a signal to a predetermined position of a feedback loop having a delay and extracts a signal from another predetermined position, and has a peak of a filtering frequency for each predetermined frequency determined by the delay length. is there. By making the frequency characteristics of the plurality of comb filters connected in parallel different, the resonance effector as a whole can have complicated frequency characteristics. The device shown in FIG. 9 is a resonance effector in which a plurality of waveguide networks are connected in parallel via a junction. In the waveguide, a feedback loop is formed by two delays, and a signal is input and output at a connection portion of each delay. Each waveguide is given a specific frequency characteristic by the delay length, and after the signals of all the waveguides are synthesized at the junction, and the signals are dispersed in each waveguide, the overall resonance effector Can obtain extremely complicated frequency characteristics.

In the resonance effectors of FIGS. 8 and 9, a filter is inserted in each delay feedback loop. This filter is composed of various filters such as LPF, HPF or APF. Further, the circuit configuration can take various configurations such as FIR and IIR. Also, the connection form of the comb filter and the waveguide is not limited to the above, and there are various variations. Further, as another method of configuring the resonance effector, there is a method in which an actual impulse response of a resonator is directly used as a coefficient.
It is also conceivable to use an R filter.

[0005]

Although these resonance effects are very similar in structure to reverb, each reverb adjusts each delay length and parameter so that the frequency characteristics are not biased as much as possible. In the resonance effect, each parameter is set so that the frequency characteristics are made to resemble a resonator of a natural musical instrument. For this reason, depending on the frequency of the input signal, an unfavorable phenomenon that abnormally strong resonance may occur may occur. For example, when the fundamental frequency of the input signal overlaps a certain peak in the resonance frequency characteristic, the resonance becomes too strong, and the volume of the resonance output becomes unusually large or the lingering sound becomes longer by the pitch. was there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a resonance effect imparting device which solves the above-mentioned disadvantage by attenuating a frequency component causing abnormal resonance.

[0007]

According to a first aspect of the present invention, there is provided a resonance tone generating means for adding a resonance tone having a predetermined resonance frequency to an input tone tone signal, and a frequency of the input tone tone signal. A frequency detecting means for detecting the frequency and / or an attenuating means for attenuating a frequency detected by the frequency detecting means and / or an overtone frequency thereof. It is characterized in that it is connected bidirectionally via a unit.

[0008] The invention of claim 2 of this application is characterized in that the tone signal is input from the junction section.

The invention of claim 3 of the present application is based on claim 1,
In 2 of the invention, the damping means, characterized that you change the resonance frequency of the resonance signal forming means according to the frequency which the frequency detection means detects.

According to a fourth aspect of the present invention, there is provided a resonance tone generating means for adding a resonance tone having a predetermined resonance frequency to an input musical tone signal, and a peak frequency is detected from an output signal of the resonance tone formation means. It is characterized by comprising a peak frequency detecting means, and an output signal attenuating means for attenuating the level of the frequency component detected by the peak frequency detecting means from the output signal of the resonance forming means.

According to the first aspect of the present invention, the resonance sound forming means adds a resonance sound having a predetermined resonance frequency to the tone signal. Since the resonance sound forming means has a predetermined resonance frequency characteristic, there is a possibility that abnormal resonance occurs depending on the frequency of the input tone signal. Thus, the frequency detecting means detects the frequency of the input musical tone signal, and the attenuating means attenuates the detected frequency and / or its overtone frequency. Since the resonance sound forming means and the damping means are connected to each other via the junction, the tone signal input to the resonance sound forming means has its fundamental frequency and harmonic frequency attenuated by the damping means. Abnormal resonance does not occur.

According to the second aspect of the present invention, since the tone signal is input from the junction section, the signal is equally input to the resonance generating means and the attenuating means, so that the resonance signal is formed and the specific frequency is adjusted. The component attenuation can be compatible.

According to the third aspect of the present invention, the resonance sound forming means adds a resonance sound having a predetermined resonance frequency to the tone signal. Since the resonance sound forming means has a predetermined resonance frequency characteristic, there is a possibility that abnormal resonance occurs depending on the frequency of the input tone signal. Therefore, the frequency detecting means detects the frequency of the musical tone signal, and the resonance frequency control means changes the resonance frequency of the resonance sound forming means according to the detected frequency. By changing the frequency of the tone signal so that it does not match the resonance frequency, abnormal resonance does not occur.

According to the invention of claim 4 of this application, the resonance sound forming means adds a resonance sound having a predetermined resonance frequency to the tone signal. Since the resonance sound forming means has a predetermined resonance frequency characteristic, there is a possibility that abnormal resonance occurs depending on the frequency of the input tone signal. Therefore, the peak frequency detecting means detects the peak frequency from the output signal of the resonance sound forming means, and the output signal attenuating means reduces the level of this peak frequency component from the output signal. As a result, even if abnormal resonance occurs, the peak frequency is attenuated, thereby preventing abnormal resonance.

[0015]

FIG. 1 is a basic block diagram of a resonance effector according to an embodiment of the present invention. FIG. 2 is a diagram showing a form in which the resonance effector is connected to another device.

In FIG. 1, this resonance effector comprises a resonance section 1 composed of junctions 3, 4 and a plurality of waveguides 5, and an abnormal resonance prevention filter 2 having the same configuration as a physical model sound source. . The plurality of waveguides 5 of the resonance section 1 have junctions 3 and 4 at both ends.
Interconnected. Each waveguide 5 has the same configuration as that shown in FIG. 9, and simulates the propagation of air vibration in a pipe and the propagation of plate vibration. In the junctions 3 and 4, the input terminals and output terminals of all the waveguides 5 are connected by an adder 6, and the signals output from all the waveguides 5 are mixed and then input to all the waveguides 5 again. Is done. Note that a coefficient multiplier 7 is connected to the output terminal of each waveguide 5, and different coefficients are input to each of them to perform unique weighting. Further, the abnormal resonance prevention filter 2 is connected to the adder 6 of the junction 3.

Here, the reason why the abnormal resonance prevention filter 2 has the same configuration as the physical model sound source will be described. In a resonance device using an electronic circuit, abnormal resonance occurs due to coincidence of resonance frequencies. However, in a natural musical instrument, a phenomenon corresponding thereto does not cause much problem. The reason is that in a natural musical instrument, the law of conservation of energy is established between a vibrating body (such as a guitar string) and a resonator (such as the body of a guitar) (FIG. 7A).
reference). Since the vibrator and the resonator exchange signals with each other, when the resonance on the resonance side increases, signals of opposite phases return from the resonator to the vibrator, thereby suppressing the vibration amplitude of the vibrator. .

It is known that a physical model sound source using a delay feedback circuit can realize an effect that satisfies this energy conservation rule by connecting the resonance effect bidirectionally (FIG. 7 (B)). )reference). Therefore, if we take a closer look at the physical model sound source using a delayed feedback circuit and the bidirectional connection of the resonance effect, the delayed feedback sound source generates a musical tone, receives a signal from resonance, and responds to it with a new signal. It turns out that it works also as a filter which returns a signal. That is, it has both a function as a sound source and a function as a filter. Therefore, when the two functions are considered separately, the result is as shown in FIG. If this configuration is used as a resonance effect, an effect that does not cause undesired resonance with a sound source such as PCM other than the physical model, an actual instrument such as a guitar, or an audio signal can be realized.

In FIG. 1, an abnormal resonance prevention filter 2
Has a delay feedback loop including a delay 8, a filter 9, a coefficient multiplier 10, and an adder 11.
A signal from the resonance unit 1 (adder 6) is input to the adder 11 of this loop. In the adder 11, the adder 6
Since the signal input from is inverted and input,
When the signal level input to the adder 11 increases, the level of the signal fed back in the loop decreases, and when the signal level input to the adder 11 decreases, the level of the signal fed back in the loop increases. Thereby, abnormal resonance of the resonance sound can be suppressed. Further, a signal is extracted from between the coefficient multiplier 10 and the adder 11 and input to the coefficient multiplier 12. The coefficient multiplier 12 multiplies the extracted signal by a predetermined coefficient and inputs the signal to the adder 6 in the resonance section. Also, this adder 6
Receives a tone signal from outside. The relationship between the plurality of waveguides 5, the abnormal resonance prevention filter 2, and the input level and output level of the input tone signal satisfies the law of conservation of energy, and there is no gain or loss.

The tone signal input to the adder 6 is transmitted to both the resonance section 1 and the abnormal resonance prevention filter 2 connected to the adder 6. That is, the musical tone signal is transmitted to the resonance unit 1 and added with a resonance sound having a specific frequency characteristic (resonance frequency), and transmitted to the abnormal resonance prevention filter unit 2 to attenuate a predetermined frequency.

The most frequent occurrence of abnormal resonance in this resonance effector is when the frequency of the input tone signal or its integral harmonic component matches the resonance frequency of the resonance unit 1. In order to prevent this, the abnormal resonance prevention filter 2 is always operated so as to suppress the frequency of the tone signal. Since the frequency characteristic of the abnormal resonance prevention filter 2 is determined by the delay length of the delay 8, the resonance effector includes a PD conversion circuit (frequency / delay length conversion circuit) 13, and converts the frequency of the input musical sound signal to the P.
The signal is input to the D conversion circuit 13 and the delay feedback loop (delay 8, filter 9, coefficient multiplier 10, adder 1)
The delay length of the delay 8 is determined so that the resonance frequency of the loop (1) becomes this frequency. As a result, the resonance frequency (attenuation frequency) of the abnormal resonance prevention filter 2 is always set to the input tone signal frequency, and even when the tone signal frequency matches the resonance frequency of the resonance unit 1, the signal level is abnormally high. Prior to this, the amplitude is suppressed by the abnormal resonance prevention filter 2 and abnormal resonance does not occur.

If the frequency of the input signal is known in advance by information such as a key code in a control unit like an electronic musical instrument (see FIG. 2A), the frequency information may be used. If a signal such as a guitar or voice is input by a microphone or a pickup, a frequency detection circuit may be provided and this frequency information may be input to the PD conversion circuit 13.

FIG. 3 is a diagram showing an example of a resonance effector constructed by connecting a plurality of abnormal resonance prevention filters to the resonance section of FIG. A plurality (4 in the figure) for one resonance unit 20
) Is connected. The plurality of abnormal resonance prevention filters 21 are connected to the junction of the resonance unit 20 in the same manner as the abnormal resonance prevention filter 2 of FIG.

Since a plurality of abnormal resonance preventing filters 21 are provided, the resonance frequency of the delay feedback loop of each abnormal resonance preventing filter 21 is set in accordance with each tone signal frequency even when a plurality of musical tone signals are input. This can prevent any tone signal from causing abnormal resonance. A PD conversion circuit 22 is connected to each abnormal resonance prevention filter 21, and sets a resonance frequency (delay length) of the corresponding abnormal resonance prevention filter 21. A frequency detection circuit 23 is connected to the PD conversion circuit 22. The frequency detection circuit is connected to the input section of the musical tone signal, and detects the frequencies of a plurality of inputted musical tones. In the figure, four frequency detection circuits 23 are connected to the same signal line. However, when a plurality of (four) tone signals are input from different signal lines, respectively, You may make it connect. However, it is better to have pitch information of individual musical tones even if there are a plurality of sounds. Even when a double tone is input from a single signal line, if the frequency of the double tone can be detected individually by an electronic musical instrument or a guitar equipped with individual string independent pickups, the frequency information is stored in each PD. What is necessary is just to input to the conversion circuit 22.

Also, a plurality of resonance effectors each composed of a combination of a resonance section and an abnormal resonance prevention filter may be provided in parallel to cope with multiple sounds.

FIG. 4 is a diagram showing a resonance effector according to another embodiment of the present invention. This resonance effector does not use an abnormal resonance prevention filter, but prevents abnormal resonance by adjusting the parameters of the resonance section 30 in accordance with the frequency of the input musical sound signal. The input tone signal is input to the resonance unit 30 and also to the frequency detection circuit 32 and the adder 33 for output. Resonance part 3
The tone signal to which resonance has been added at 0 is input to the adder 33, and is added to the direct signal and output.

The resonance section 30 has a configuration similar to that of the resonance section 1 shown in FIG. 1. By changing parameters such as a loop gain (gain in a delay loop) and a delay length, the resonance frequency and the gain at the time of resonance are changed. Can be changed. A key scale table 31 is connected to the resonance section 30. The key scale table 31 stores parameter values such as the loop gain and the delay length that are set corresponding to various frequencies of the input tone signal. The key scale is set so that the frequency of the input tone signal does not match the resonance frequency of the resonance unit 30, and the gain is reduced when the input signal frequency and the resonance frequency of the resonance unit 30 are close to each other. Are set so that abnormal resonance does not occur. In this embodiment, the table is stored as a table. However, a calculation formula may be stored, and the parameter value may be calculated based on the input frequency information.

The frequency detecting circuit 32 detects a fundamental frequency from the input tone signal. This frequency information is input to the key scale table 31. Thereby, the operation of the resonance unit 30 can be automatically controlled so as not to cause abnormal resonance in response to the input signal.

In order to deal with multiple tones, the key scale table 31 and the frequency detection circuit 32 may be connected in parallel by the number of sounds as shown in FIG. , The key scale table 31 and the frequency detection circuit 32 may be connected to each signal line.
With such connection, the input gain to the resonance unit can be individually controlled.

FIG. 5 is a block diagram showing still another embodiment of the present invention. In the above-described embodiment, the abnormal resonance prevention filter or the resonance unit is controlled based on the frequency of the input tone signal. In this embodiment, the peak level of the tone signal output from the resonance unit is detected and detected. Is to cut. That is, when a plurality of tone signals are input, it is difficult to control the abnormal resonance prevention filter or the resonance unit for each tone signal in advance. Therefore, the input tone signal is passed through the resonance section as it is, and when an abnormal resonance peak is detected from the output signal, the output of the resonance section is filtered so as to eliminate the peak. .

The tone signal is input not only to the resonance section 40 but also to an adder 46 for output. The resonance section 40 gives a resonance effect to the input musical tone signal. The output of the resonance section 40 is input to an adder 45, and the peak frequency detection section 4
1 is input to a band pass filter (BPF) 42.
The peak frequency detection unit 41 may be configured by a combination of a filter bank of FFT or BPF and a PLL.
The peak frequency detected by such a circuit is input as a coefficient of the band-pass filter 42. The band-pass filter 42 extracts only the component of the peak frequency detected by the peak frequency detection unit 41 from the output signal of the resonance unit 40.
The extracted frequency components are input to the coefficient multiplier 44 and the level detector 43. The level detector 43 determines the level of the frequency component, that is, the peak level, and determines how much the frequency component is attenuated. The determination of the amount of attenuation is determined so as not to cause abnormal resonance while maintaining the peak.
The output of the coefficient multiplier 44 is sent to the adder 45 by the resonance section 40.
Is inverted and added (subtracted) to the output signal of
The larger the coefficient (0 to 1) output from the level detector 43, the larger the attenuation of the peak frequency component. Therefore, when this frequency component is completely attenuated, the level detector 43 outputs a coefficient 1 to the coefficient multiplier 44,
When no attenuation is performed, a coefficient 0 is output. Adder 4
The resonance signal from which the peak frequency component has been cut in 5 is added to the direct signal (through signal) in the adder 46 and then output.

FIG. 6 is a block diagram showing a resonance effector according to a fourth embodiment of the present invention. This resonance effector includes an abnormal resonance preventing filter, and the characteristic of the abnormal resonance preventing filter is controlled based on the output signal of the resonance section. In the embodiment of FIG. 3, the resonance frequency of the abnormal resonance prevention filter is set based on the frequency of the input signal. In this embodiment, however, the peak is eliminated based on the signal level of the peak frequency of the output signal. Then, the parameters of the resonance section and the parameters of the abnormal resonance prevention filter are moved.

The input tone signal is input to the resonance section 50 and an output adder 56. The resonance section 50 adds a resonance sound to the input tone signal. Also, the resonance unit 50
, A plurality of abnormal resonance prevention filters 51 are connected in parallel. A PD conversion circuit 55 is connected to each of the abnormal resonance prevention filters 51. Resonance (suppression) of the abnormal resonance prevention filter 51 by the PD conversion circuit 55
The frequency is determined. The output of the resonance unit 50 is input to the adder 56 and also to the peak frequency detection unit 54 and the bandpass filter 52. The peak frequency detection section 54 detects a peak frequency of the signal output from the resonance section 50. This peak frequency detector 54 may have the same configuration as the peak frequency detector 41 of the embodiment of FIG. The peak frequency detected by the peak frequency detector 54 is input to the band pass filter 52 and the PD conversion circuit 55. The band-pass filter 52 extracts only the detected peak frequency component and outputs it to the level detection unit 53. The level detection unit 53 changes a parameter (gain) of the resonance unit 50 and / or the abnormal resonance prevention filter 51 according to the level of the input peak frequency component. That is, when the peak level is extremely high, the resonance unit 5
The loop gain of 0 is reduced, and the gain (suppression rate) of the abnormal resonance prevention filter 51 is increased. Also, P
The D conversion circuit 55 includes an abnormal resonance prevention filter 5 that resonates at the peak frequency detected by the peak frequency detection unit 54.
Set a delay length of 1. As a result, the level of the peak frequency at which abnormal resonance is likely to occur can be reduced, and the resonance frequency can be shifted, whereby abnormal resonance can be prevented.

[0034]

As described above, according to the present invention, abnormal resonance does not occur even when the fundamental frequency and harmonic components of the input signal coincide with the frequency emphasized by the resonance section, and the resonance section resembles the resonance section of a natural musical instrument. Resonance characteristics can be obtained.

As described above, according to the first aspect of the present invention, it is possible to eliminate the abnormal resonance of the resonance sound forming means by detecting the frequency of the input tone signal and attenuating this frequency and its overtone frequency. it can.

According to the second aspect of the present invention, since the tone signal is input from the junction, the signal is equally input to the resonance generating means and the attenuation means, and the resonance is formed and specified. Attenuation of frequency components can be compatible.

According to the third aspect of the present invention, abnormal resonance is eliminated by detecting the frequency of the input tone signal and changing the resonance frequency of the resonance sound forming means so as not to coincide therewith. Can be.

According to the fourth aspect of the present invention, abnormal resonance can be prevented by detecting the peak frequency of the output signal of the resonance sound forming means and reducing the level of the peak frequency component. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a resonance effector according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state where the resonance effector is incorporated in an electronic musical instrument.

FIG. 3 is a diagram showing a configuration in which the resonance effector is adapted for multiple sounds.

FIG. 4 is a configuration diagram of a resonance effector according to a second embodiment of the present invention;

FIG. 5 is a configuration diagram of a resonance effector according to a third embodiment of the present invention;

FIG. 6 is a configuration diagram of a resonance effector according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating the configuration principle of an abnormal resonance prevention filter.

FIG. 8 is a diagram showing a configuration of a conventional resonance effector.

FIG. 9 is a diagram showing a configuration of a conventional resonance effector.

[Explanation of symbols]

1,20,30,40,50-resonance part (resonance sound forming means), 2,21,51-abnormal resonance prevention filter (attenuation means).

Continuation of the front page (56) References JP-A-7-199936 (JP, A) JP-A-7-20859 (JP, A) JP-A-7-219531 (JP, A) JP-A-6-67672 (JP) JP-A-5-66768 (JP, A) JP-A-6-43863 (JP, A) JP-A-61-49516 (JP, A) JP-A-63-40199 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G10H 7/08 G10H 1/00

Claims (4)

(57) [Claims] 1. A resonance tone generator for adding a resonance having a predetermined resonance frequency to an input tone signal, a frequency detector for detecting a frequency of the input tone signal, and Attenuating means for attenuating the frequency and / or its overtone frequency, wherein the resonance sound forming means and the attenuating means are bidirectionally connected via a junction portion where both output signals are synthesized. A resonance sound adding apparatus characterized by the above-mentioned. 2. The resonance adding apparatus according to claim 1, wherein the tone signal is input from the junction. 3. The resonance sound adding apparatus according to claim 1 , wherein said attenuation means changes a resonance frequency of said resonance sound generation means according to a frequency detected by said frequency detection means. 4. A resonance sound generating means for adding a resonance sound having a predetermined resonance frequency to an input musical sound signal; a peak frequency detection means for detecting a peak frequency from an output signal of the resonance sound generation means; An output signal attenuating means for attenuating the level of the frequency component detected by the peak frequency detecting means from the output signal of the sound forming means.