JP2822860B2 - 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 provided with an automatic key scaling device for automatically performing key scaling in a so-called delayed feedback sound source.

[0002]

2. Description of the Related Art Hitherto, a so-called delayed feedback sound source has been proposed as a sound source for forming a desired musical sound waveform (see Japanese Patent Application Laid-Open No. 58-48109). FIG. 2 shows a schematic configuration thereof.

In FIG. 1, reference numeral 101 denotes an excitation waveform generator for storing a basic tone waveform and generating the tone waveform. The excitation waveform generator 101 reads out the stored tone waveform from the stored tone waveforms. A signal WAVE for designating a desired musical sound waveform, a signal TO indicating a strength of a player playing a keyboard or the like.
UCH, signal K indicating output of read-out musical sound waveform
ON is input, and the initial musical tone waveform is read out and output according to these signals. The initial tone waveform output in this manner is added to the output from the variable amplifier 103 by the adder 102, and the addition result is supplied to the filter 104. A signal FC for controlling the filter coefficient is input to the filter 104, and the filter 104
Based on the filter coefficient determined by C, the result of the addition is filtered to color the musical tone. The signal output from the filter 104 is extracted outside as a tone signal, and is fed back to the adder 102 via a feedback loop formed by the variable delay circuit 105 and the variable amplifier 103.

Here, the variable amplifier 103 determines a loop gain and is basically for attenuating a feedback signal, and has a gain a according to an input gain signal (this value is: Depending on the characteristics of the filter 104, the filter 104 has a gain 1 (0d
B), the signal from the variable delay circuit 105 is multiplied by the signal from the variable delay circuit 105 when an attenuation sound is generated.
02 is output. Further, the variable delay circuit 105 delays the feedback signal by a delay time DLY corresponding to the input delay amount signal. The delay caused by the variable delay circuit 105, more specifically, the filter 104
The pitch (frequency) of the musical sound is determined according to the delay amount including the delay due to the above.

In the electronic musical instrument described above, a comparison between a case where a high-tone musical tone is output and a case where a low-tone musical tone is output indicates that the high-tone musical tone has a high frequency and thus the delay amount is small, while the low-tone musical tone is low. Since the tone of the musical interval has a low frequency, it is necessary to increase the delay amount. That is, in order to output a musical tone with a high pitch, the number of times the initial musical tone waveform passes through the feedback loop becomes larger than that in outputting a musical tone with a low pitch. Therefore, the number of gains multiplied by the variable amplifier 103 is higher in a high-tone musical tone than in a low-tone musical tone, and when the same value of gain is used, a high-tone musical tone has a higher musical tone than a low-tone musical tone. This is because the duration of the time is shortened.

For example, to generate a tone of 440 Hz, 440 gain multiplications are performed per second, while to generate a double 880 Hz tone, 880 gains are multiplied per second. . Therefore, when the tone waveforms of the respective frequencies are generated with the same gain in the same initial tone waveform, the attenuation rate of the 880 Hz tone is 440 Hz.
Double the musical tone of That is, each time the octave interval is raised, the attenuation rate is doubled.

[0007] In order to solve this problem, a method for correcting the sound to be flat so that the duration is not extremely changed by a musical tone to be generated by setting a break point, and a method of correcting the table data to be flat. A method of changing the gain value in accordance with a musical tone to be generated and correcting the gain so as to be flat is used.

[0008]

However, in the above-described conventional electronic musical instrument, the method of setting and correcting breakpoints requires changing the point at which breakpoints are set for each musical tone, thus complicating the processing. On the other hand,
Even in the method using the table data, the gain value must be stored as the table data for each musical tone, so that the memory capacity increases, which leads to an increase in cost. Further, in a conventional electronic musical instrument, when a desired musical tone is designated, the gain value is set to a predetermined fixed value in accordance with the designation, so that the player can freely set the duration of the musical tone. I couldn't.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to reduce the cost by simplifying the processing procedure, reducing the memory capacity, and allowing the player to freely set the duration of the musical sound. It is an object of the present invention to provide a musical sound synthesizer or an electronic musical instrument capable of widening the range of performance by using the same.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises connecting a delay means for delaying a signal by a predetermined amount of delay and an attenuation means for attenuating the signal by a predetermined amount of attenuation in a closed loop. A closed loop means for circulating a signal; and an excitation signal generating means for generating an excitation signal and supplying the excitation signal as the input signal to the closed loop means, and extracting a tone signal by extracting a signal circulating through the closed loop means. A musical tone synthesizer for synthesizing, a pitch information generating means for generating pitch information indicating a pitch of the musical tone signal to be synthesized; a setting means for setting attenuation rate information indicating an attenuation rate of the musical tone signal; Delay amount control means for controlling the delay amount of the delay means according to the generated pitch information; and four arithmetic operations of the generated pitch information and the set attenuation rate information. Therefore, the attenuation amount of the attenuation unit is approximately calculated, and the signal is attenuated by the attenuation unit by the calculated attenuation amount, so that the attenuation rate of the musical tone signal is reduced regardless of the pitch indicated by the pitch information. And an attenuation control unit for making the attenuation constant.

[0011]

The pitch information generated by the pitch information generating means and the attenuation rate information set by the setting means are arithmetically operated to calculate the attenuation of the attenuation means approximately. The signal is attenuated by the attenuating means, whereby the attenuation rate of the tone signal taken out of the closed loop means is made constant irrespective of the pitch indicated by the pitch information.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In this embodiment, as a sound source for generating a musical tone,
The sound source of FIG. 2 described in the related art is used.

First, the principle of the present invention will be described.

The fundamental pitch of the generated musical tone is p (Hz)
Assuming that the gain of the variable amplifier 103 in FIG. 2 is a (here, a filter or the like is designed so that a represents a loop gain), the attenuation rate d (1 / se
c) is represented by the following equation (1).

D = a ＾ p (0 <a <1) ‥‥ (1) When this is solved for a, the following equation (2) is obtained.

A = d ＾ (1 / p) ‥‥ (2) Here, “＾” indicates that the mathematical expression immediately after that is a power.

Therefore, if the key scaling is performed for each musical tone to be generated using this "a", the above-mentioned problem can be solved. However, if the accuracy is sacrificed to some extent, a key scaling device in which the processing is simplified can be realized. can do.

In equation (1), generally, when an attenuated sound is generated, “a” is smaller than “1” but very close to “1”. As described with reference to FIG. 2, since the number of times that the initial tone waveform passes through the feedback loop formed by the variable amplifier 103 and the variable delay circuit 105 is very large, if the gain is not substantially equal to "1", the duration of the tone will be long. Is too short to be realized as a musical tone.
Here, if a = 1−b, the above equation (1) is represented as the following equation (3), and “b” is “0”.
Equation (3) can be approximated as Equation (4) below.

D = (1-b) ＾ p ‥‥ (3) d = 1-p * b ‥‥ (4) When this equation (4) is solved for “b”, the following equation (5) is obtained. When “a” is obtained based on the equation (5), the following equation (6) is obtained.

B = (1-d) / p ‥‥ (5) a = 1-b = 1- (1 / p) * (1-d) ‥‥ (6) In the present embodiment, the principle described above is used. Is applied to an electronic musical instrument.

FIG. 1 is a block diagram showing a schematic configuration of an electronic musical instrument provided with an automatic key scaling device according to this embodiment.

In FIG. 1, reference numeral 1 denotes a keyboard, which detects a pressed state of a player and outputs pitch information, touch intensity (velocity), and sound generation request to the control unit 2. Further, the control unit 2 is connected with a performance operator 3 including a switch for setting the duration of the musical tone, that is, a switch for changing the pitch, a switch for changing the pitch, and a tone setting operator 4 for setting the tone of the musical tone. Based on the information from these elements 1, 3, and 4, the control unit 2 uses the parameters (signal WA) described in FIG.
VE, TOUCH, KON) and other parameters (signals PITCH, TC, d). Here, the signal PITCH is a signal representing the pitch of the output musical tone, and its value corresponds to “p” described in the above equation (1) and the like. The signal TC indicates the tone color of a musical tone determined according to the key pressed by the player and the tone color set by the tone setting operator 4, and the signal d indicates the attenuation rate d set by the performance operator 3. It is an attenuation rate signal shown.

The signal PITCH has a delay time DLY of FIG.
Is supplied to a delay parameter generator 5 that generates a delay amount signal for controlling the filter coefficient, and is also supplied to a filter coefficient generator 6 that generates a signal FC for determining the filter coefficient in FIG. The signal TC and the signal TOUCH from the keyboard 1 are also supplied to the filter coefficient generator 6, and the filter coefficient generator 6 generates a signal FC for coloring a musical tone in accordance with the three signals. Occurs and determines the filter coefficients.

Further, the signal d is supplied to the negative input terminal of the adder 7, and "1" is input to the positive input terminal of the adder 7.
Is supplied. “1” is also supplied to the input terminal on the positive side of the adder 8. The output of the adder 7 is supplied to one input terminal of a multiplier 9, and the other input terminal of the multiplier 9 is supplied with the reciprocal of the signal PITCH via a reciprocal converter 10. Then, the output of the multiplier 9 is supplied to the negative input terminal of the adder 8, and the output of the adder 8 becomes a gain signal for controlling the gain a in FIG. That is, the elements 7 to 10 are configured to perform the operation of the equation (6).

The control unit 2 and the elements 5 to 10 described above
By supplying the signal generated by the above to the sound source of FIG. 2 as a parameter, the duration of the musical sound can be freely changed, and the width of the performance can be further expanded. Further, since a desired gain a can be obtained from the attenuation rate d by the elements 7 to 10, the processing procedure is simplified, and the memory capacity is reduced by not using a table.
As a result, cost can be reduced.

In the present embodiment, the duration of the musical tone is set as the attenuation rate d by the performance operator 3, but is automatically determined in accordance with the key pressed by the player and the setting of the tone by the tone setting operator 4. You may make it. At this time, the attenuation rate may be stored as table data, and may be read from the table data in accordance with key depression, tone color setting, and the like.

In this embodiment, the gain is obtained by the approximate expression of the above equation (6). However, strict key scaling is performed by performing the exponentiation operation shown in the above equation (2). You may comprise. In this case, instead of the elements 7 to 9 in FIG. 1, a power exponentiation circuit which outputs the exponentiation using the attenuation rate d and the output (1 / PITCH) of the reciprocal converter 10 as an input signal may be used.

Further, the gain a of the multiplier 103 is determined by the gain characteristic of the filter 104 or the coefficient FC.
May be corrected (correction is performed so that the loop gain maintains a desired value).

In this application example, each element is configured by hardware, but the DSP (Digital Signal Process) is used.
or) and a microprogram.

The method of generating the initial waveform output from the excitation waveform generator 101 in FIG. 2 may be any method such as a waveform memory reading method and an FM method. Furthermore, the initial waveform need not be a musical tone, for example,
It may be a noise (random number) or an output waveform of various sensors (for example, an impact sensor).

Further, in the present embodiment, the present invention is used for controlling the duration of a musical tone. However, the present invention is not limited to this. For example, an effector to which delayed feedback is applied (for example, a resonance string effect or a resonance body effect is used). It can also be used for coefficient control of what occurs.

[0033]

As described above, according to the present invention,
The pitch information generated by the pitch information generating means and the attenuation rate information set by the setting means are arithmetically operated, and the attenuation of the attenuation means is approximately calculated, and the calculated attenuation is calculated by the attenuation means. The signal is attenuated, whereby the decay rate of the tone signal taken out of the closed loop means is made constant irrespective of the pitch indicated by the pitch information, so that the duration of the synthesized tone is determined by the pitch of the tone. Irrespective of. Further, since the attenuation amount is calculated by an operation, a storage unit for storing the attenuation amount is not required. Therefore, the hardware configuration can be simplified and the manufacturing cost can be reduced. Further, since the attenuation is approximately calculated by the four arithmetic operations, the attenuation can be calculated at a high speed, thereby preventing problems such as delay in sound generation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an electronic musical instrument provided with an automatic key scaling device according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a conventional sound source for forming a musical sound waveform.

[Explanation of symbols]

 1 keyboard (pitch information generation means) 2 control unit (delay amount control means, attenuation amount control means)3 arithmetic operators (setting means)  Reference Signs List 5 delay parameter generation unit (delay amount control means) 7, 8 adder (attenuation amount control means) 9 multiplier (attenuation amount control means) 10 reciprocal conversion unit (attenuation amount control means) 101 excitation waveform generation unit (excitation signal generation) Means) 102 adder (loop means) 103 variable amplifier (attenuation means) 105 variable delay circuit (delay means)

Claims (1)

(57) [Claims] 1. A delay unit for delaying a signal by a predetermined delay amount.
Close the stage and the attenuation means that attenuates the signal by the specified amount.
Closed loop means connected in a loop and circulating the input signal
Generating an excitation signal, and using the excitation signal as the input signal.
Excitation signal generating means for supplying the excitation signal to the closed loop means.
To extract the signal circulating through the closed loop means.
A tone synthesizing device for synthesizing a tone signal further, wherein pitch information indicating a pitch of the tone signal to be synthesized is generated.
Pitch information generating means,Setting for setting attenuation rate information indicating the attenuation rate of the tone signal
Means, Said The delay amount of the delay means according to the generated pitch information
Delay control means for controlling the generated pitch informationAnd the set attenuation rate information
By performing four arithmetic operations on the information,
Calculating the amount of attenuation, and calculating the amount of attenuation by the calculated amount of attenuation.
To attenuate the signalBy doingSaidSound indicated by pitch information
Attenuation of the tone signal regardless of heightrateAttenuation to keep
A musical sound synthesizer comprising a control means.