JP3341777B2 - Effect giving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an effect imparting device for imparting various effects to an input musical tone waveform signal and outputting the signal.

[0002]

2. Description of the Related Art Conventionally, there has been known an effect imparting device for imparting various effects to a musical tone waveform signal. The effects to be given are, for example, reverberation (reverb),
There are delays, choruses, exciters, and distortions. When a so-called delay system effect such as reverb or delay is provided, a process of delaying an input signal which is a digital signal using a shift register or a random access memory (RAM) is performed.

For example, in reverb, a tone signal sequentially input at a predetermined sampling frequency is stored in a RAM, and when a new input is received, the input is stored and a predetermined number of tone signals input in the past are also stored. In advance, processing is performed to generate a tone signal to which a reverb effect has been applied from these data. Reverb time (reverberation time), delay time, and the like are determined by the delay time of the RAM, and the delay time depends on the capacity of the RAM used for the delay processing. That is, in order to realize a double delay time, a RAM having a double capacity is required.

[0004]

When it is desired to increase the reverberation time or delay time, the above-mentioned RAM is required.
Has to increase the capacity. However, when the capacity of the RAM is increased, the delay time is increased, but the cost is increased.

On the other hand, as described above, there are various types of effects to be imparted to the tone signal, but the effects requiring a large-capacity RAM are not so many. Therefore, a large-capacity RAM is used to provide a few types of effects.
And it was very uneconomical.

The present invention has been made in view of the above-mentioned problems in the prior art, and provides an effect providing apparatus which can realize a larger delay time using a RAM having a smaller capacity and can provide various effects. Aim.

[0007]

In order to achieve the above object, the present invention provides an effect applying apparatus for inputting a digital musical tone waveform signal, applying various effects to the digital musical tone waveform signal, and outputting the digital musical tone waveform signal. 1st effect or 2nd
Effect selecting means for selecting the effect of the first step, and when the first effect is selected by the effect selecting means, outputting the input digital musical tone waveform signal of the first sampling frequency without changing the same, Means for converting the input digital tone waveform signal of the first sampling frequency into a digital tone waveform signal of the second sampling frequency and outputting the digital tone waveform signal of the second sampling frequency when the second effect is selected by the means; An effect imparting means for imparting an effect selected by the effect selecting means to the digital musical tone waveform signal output from the changing means and outputting the signal.

After the effect is given by changing the sampling frequency, it is preferable to return to the original sampling frequency again.

[0009]

The effect applying means operates at an operating frequency dependent on the sampling frequency of the input digital tone waveform signal. When the operating frequency in the effect applying means is changed, writing and reading to and from the storage means used for delaying the tone signal by the effect applying means are also performed at the operating frequency. Therefore, for example, when the second effect (the effect of increasing the delay time) is to be applied, the sampling frequency of the tone waveform signal to be input is reduced, and the operating frequency of the effect applying unit is also reduced accordingly. However, the delay time can be extended even if the capacity is small. When the first effect is selected, the effect can be applied without changing the sampling frequency from the beginning as in the conventional case.

[0010]

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 an effect applying device according to one embodiment of the present invention is applied. The electronic musical instrument of this embodiment includes a keyboard 1, a keyboard interface 2, a random access memory (RAM) 3, a read only memory (ROM) 4, a central processing unit (CPU) 5,
Panel 6, panel interface 7, sound source 8, effect imparting unit 9, sound system 10, and bus line 11
It has.

The keyboard 1 has a plurality of keys for the user to operate (play). The keyboard interface 2 detects an operation of the keyboard 1 and outputs performance information corresponding to the operation to the bus line 11. Various work areas, flags, and the like are assigned to the RAM 3, and these are accessed by the CPU 5. The ROM 4 stores programs executed by the CPU 5, tables, and the like. Also ROM
Reference numeral 4 stores an effect imparting program executed by the effect imparting unit 9. The CPU 5 controls the overall operation of the electronic musical instrument.

The panel 6 is a panel section of the electronic musical instrument, and is provided with various switches for operation by a user. Reference numeral 61 denotes ten tone color selection switches for selecting a tone, 62 denotes four effect selection switches for selecting an effect to be applied to a musical tone, and 63 denotes a slider operator. The effect selection switch 62 is a reverb switch 62
-1, chorus switch 62-2, exciter switch 62-3, and distortion switch 62-4
Consists of The panel interface 7 detects an operation of a switch or the like on the panel 6 and outputs the operation information to the bus line 11.

When the user operates the keyboard 1, performance information (key-on signal, key code, key touch information, etc.) is input from the keyboard 1 via the keyboard interface 2 and the bus line 11 to the CPU 5. The CPU 5 instructs the sound source 8 to generate sound based on the performance information. The sound source 8 generates a tone signal with a predetermined tone based on an instruction from the CPU 5. The sampling frequency of the tone signal generated from the sound source 8 is set to 50 kHz. That is, the tone signal output from the sound source 8 is a sequence of digital data (data representing the amplitude value of the tone waveform) sequentially output every 1 / 50,000 second.

The tone color of the generated tone is selected by a tone selection switch 6.
1 can be selected. That is, when the user presses one of the tone selection switches 61, the operation information is transmitted to the panel interface 7 and the bus line 11.
Is input to the CPU 5 via the. The CPU 5 reads out the timbre parameters from the ROM 4 based on the operation information, and sends them to the sound source 8. Thereafter, the sound source 8 generates a tone signal with a tone specified by the input tone parameter.

The effect given to the generated musical tone can be selected by an effect selection switch (effect switch) 62. That is, when the user presses the reverb switch 62-1, the reverb effect is given to musical tones generated thereafter. Similarly, the user sets the chorus switch 62-
2. When the exciter switch 62-3 or the distortion switch 62-4 is depressed, a chorus, exciter, or distortion effect is applied to musical tones generated thereafter.

The effect is imparted by the effect imparting section 9. The effect imparting unit 9 includes a digital signal processor (DSP) and other circuits. When the DSP in the effect applying unit 9 executes the effect program, the effect is applied to the tone signal. The effect program executed by the DSP is loaded into the DSP according to the operation of the effect selection switch 62 by the user.

For example, when the user sets the reverb switch 62-
When the CPU 5 receives the operation information, the CPU 5
The reverb program among the effect programs is read from M4 and sent to the effect applying section 9 via the bus line 11. The sent reverb program is loaded into the DSP in the effect applying unit 9. Thereafter, D in the effect imparting section 9
The SP gives a reverb effect to the input tone signal by executing the reverb program. chorus,
Regarding the effect of the exciter or the distortion, the above operation is the same except that the loaded effect program is replaced.

The tone signal to which the effect is given by the effect giving section 9 is input to the sound system 10 and is emitted as an actual tone.

FIG. 2 shows a detailed block configuration of the effect imparting section 9. The effect imparting unit 9 includes the decimation filter 2
01, selector 202, DSP 203, selector 20
4, RAM 205, interpolation filter 20
6, a selector 207, multipliers 208 and 209, and an adder 210.

The tone signal from the sound source 8 is input to the decimation filter 201 and the
Input to the terminal and the multiplier 209. The decimation filter 201 converts a tone signal input at a sampling frequency of 50 kHz into a tone signal having a sampling frequency of 25 kHz and outputs the tone signal. Decimation filter 201
Is input to the A terminal of the selector 202.

The selector 202 outputs the input signal of the terminal A when the selection signal SS sent from the CPU 5 is "1", and outputs the input signal of the terminal B when it is "0". Therefore, when the selection signal SS is “1”, a tone signal having a sampling frequency of 25 kHz
When the selection signal SS is “0”, a tone signal having a sampling frequency of 50 kHz is input to the DSP 203 via the selector 202.

The DSP 203 executes the effect program to add a predetermined effect to the input musical tone signal and output it. The effect program to be executed is
DSP2 according to the operation of the effect selection switch 62 by the user
03 is loaded. The operating frequency of the DSP 203 is defined by a clock signal input to the DSP 203 via the selector 204.

The selector 204 sets the selection signal SS to "1".
In this case, the clock signal CK1 of 25 kHz is supplied to the selection signal S.
When S is "0", the clock signal CK2 of 50 kHz is
Each is supplied to the DSP 203. Therefore, the DSP
Reference numeral 203 denotes an operating frequency of 25 kHz when the selection signal SS is “1”, and 50 kHz when the selection signal SS is “0”.
It operates at an operating frequency of z.

The RAM 205 is used when the DSP 203 executes an effect program. For example, in a reverb program for adding a reverb effect to a musical tone, musical tone data sequentially input at each sampling period is stored in a RAM.
A process of storing the data in the memory 205 and delaying the data is performed. RAM
The access of the DSP 203 to the 205 is performed at a timing according to the operating frequency of the DSP 203.

The output of the DSP 203, that is, the tone signal after the effect is applied, is input to the interpolation filter 206 and also to the B terminal of the selector 207.
The interpolation filter 206 doubles the sampling frequency of the input tone signal and outputs it. The output of the interpolation filter 206 is input to the A terminal of the selector 207. The selector 207 is a CPU
When the selection signal SS transmitted from 5 is "1", the input signal of the A terminal is output, and when it is "0", the input signal of the B terminal is output.

When the selection signal SS is "1", the DSP 2
03, the interpolation filter 20
The sampling frequency of the tone signal which is the input to 6 is 25
kHz, the interpolation filter 20
The output from 6 is a tone signal having a sampling frequency of 50 kHz. At this time, the selector 207 selects the tone signal from the interpolation filter 206 and outputs it to the multiplier 208. When the selection signal SS is “0”, the sampling frequency of the tone signal output from the DSP 203 is 50 kHz, and this tone signal is
7 to the B terminal. At this time, the selector 207 selects the tone signal from the DSP 203 and
Output to.

The multiplier 208 multiplies the input tone signal by the effect balance coefficient BD 1 and outputs the result to the adder 210. On the other hand, the multiplier 209 multiplies the tone signal from the sound source 8 by the effect balance coefficient BD2, and
Output to 0. The adder 210 adds the output from the multiplier 208 (weighted to the tone signal to which the effect is added) and the output from the multiplier 209 (weighted to the original tone signal to which no effect is added), and calculates the addition result. It is output to the sound system 10 as a tone signal with the final effect.

In summary, when the selection signal SS is "1", the effect imparting section shown in FIG. 2 drops the sampling frequency of the input musical tone signal from 50 kHz to 25 kHz and imparts the effect with the DSP 203, and then increases the sampling frequency to 50 kHz. And output. Also, the selection signal S
When S is "0", an effect is given by the DSP 203 with the sampling frequency of the input tone signal being 50 kHz, and the signal is output as it is.

FIG. 3A shows a decimation filter 2.
1 shows a block configuration of No. 01. Decimation filter 2
01 has a low-pass filter operation unit 301 and a data thinning unit 302. A predetermined high frequency component is removed from the tone signal having a sampling frequency of 50 kHz input to the low-pass filter operation unit 301. Here, in order to remove the aliasing noise component when the sampling frequency is reduced from 50 kHz to half of 25 kHz, 12.5 kHz is used.
The cut-off frequency is set so as to remove frequency components equal to or higher than z.

The output of the low-pass filter operation unit 301 is
The data is input to the data thinning unit 302. Data thinning unit 30
2 is specifically constituted by a latch 303 shown in FIG. The latch 303 samples and holds the input signal by the clock signal CK of 25 kHz. Here, since a tone signal having a sampling frequency of 50 kHz is input, every other data is thinned out and output as a tone signal having a sampling frequency of 25 kHz.

FIG. 4 shows the interpolation filter 2
06 shows the block configuration. The interpolation filter 206 includes a data interpolation unit 401 and a low-pass filter operation unit 402. In the tone signal having a sampling frequency of 25 kHz input to the data interpolation unit 401, one zero data is interpolated between each data. Data interpolation unit 4
01 is input to a low-pass filter operation unit 402 (the cutoff frequency may be the same as that of the low-pass filter operation unit 301), where a predetermined high frequency component is removed, and a tone signal having an apparent sampling frequency of 50 kHz is input. Is output as

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

Referring to the flowchart of FIG. 5, in the main routine of this electronic musical instrument, first, in step S1
Perform initial setting. Next, panel processing (FIG. 6) is performed in step S2, keyboard processing is performed in step S3, and other processing is performed in step S4. Then, the process returns to step S2, and the subsequent processing is repeated. The keyboard processing in step S3 is
This is a process of detecting a user's performance on the keyboard 1 and instructing the sound source 8 to generate a musical tone in accordance with the performance.

Referring to the flowchart of FIG.
In the panel processing routine, first, in step S11, it is determined whether or not the reverb switch 62-1 has been pressed. If not, the process proceeds to step S14.
When the reverb switch 62-1 is pressed, the selection signal SS is set to "1" in step S12, and
In step 13, the reverb program among the effect programs is sent to the DSP 203 and loaded. The reverb program to be loaded is stored in the ROM 4 as shown in FIG.
Stored above.

Next, in step S14, it is determined whether or not another effect switch 62-2, 62-3, 62-4 has been pressed. If not, step S17
Proceed to. Effect switches 62-2, 62-3, 62
If any one of the switches is pressed, the selection signal SS is set to "0" in step S15, and the effect program corresponding to the effect switch pressed in step S16 is sent to the DSP 203 and loaded. As shown in FIG. 6B, the effect program to be loaded, that is, the chorus program, the exciter program, or the distortion program is
It is stored on OM4.

According to the above embodiment, when a reverb effect is to be applied to a musical tone, the selection signal SS becomes "1". Therefore, thereafter, in the effect imparting unit 9 of FIG.
The tone signal with a sampling frequency of 50 kHz sent from is thinned out to a sampling frequency of 25 kHz,
The reverb effect is added and the sampling frequency 5
Returned to 0 kHz. When the reverb effect is applied by the DSP 203, the RAM 205 is used to delay the tone signal. However, since the reading and writing of the RAM 205 are also performed at the operating frequency of 25 kHz, the tone signal having the sampling frequency of 50 kHz is delayed. As a result, a delay time twice as long as the delay time is obtained. Therefore, a sufficient reverberation effect with a sufficient reverberation time can be provided even with a small RAM capacity.

In the above embodiment, since the reverberation effect is provided by limiting the band and lowering the sampling frequency, the frequency characteristics are degraded. However, when giving the effect of the delay system, the reflection of the sound from the sound source is simulated by the delay using the RAM. As the characteristic of the reflected sound is faster as the frequency range of sound is attenuated, the effect of the conventional delay system is passed through a low-pass filter. Therefore, even if the reverberation effect is given by lowering the band and lowering the sampling frequency as in the above embodiment, there is no problem in terms of frequency characteristics. Further, in the above embodiment, since the tone signal to which the reverb effect is applied is mixed with the original tone signal and output, the frequency characteristics of the direct sound can be secured, and the audibility is hardly affected.

When a chorus, exciter, or distortion effect other than the effect of the delay system is applied, the selection signal SS becomes "0". Therefore, the sampling frequency 5
The tone signal of 0 kHz is given an effect by the DSP 203 as it is. In providing these effects, not much capacity of the RAM 205 is required. In addition, these effects may require frequency characteristics over a high frequency range. However, since the effects are applied with the sampling frequency kept at 50 kHz, the frequency characteristics do not deteriorate.

In the above embodiment, as described above,
Since the sampling frequency is automatically changed or left unchanged according to the effect to be applied,
A sufficient delay time can be realized by the effect of the delay system without increasing the AM capacity, and effects other than the delay system can be provided without deteriorating the frequency characteristics.

In the above embodiment, it is assumed that the reverb time is a predetermined value. However, if the reverb time can be changed, the sampling frequency may be changed according to the reverb time. That is, when the reverb time is short and the delay time is short, the processing is performed at the original sampling frequency. When the reverb time is long and the delay time is long, the capacity of the RAM 205 is not enough. May be performed.

Next, a second embodiment of the present invention will be described.
The second embodiment has the same configuration as that of the first embodiment shown in FIGS. 1 to 4 and the main routine is the same as that of FIG. 5, so that the description thereof will be omitted. The panel processing routine of FIG. 6 of the first embodiment is replaced with FIG.

Referring to the flowchart of FIG.
In the panel processing routine according to the second embodiment,
First, in step S21, it is determined whether or not the tone color selection switch 61 has been pressed. If the tone selection switch 61 has not been pressed, the process proceeds to step S26. If the timbre selection switch 61 is pressed, the timbre parameter corresponding to the timbre number selected in step S22 is transmitted to the sound source 8. The timbre parameters are stored in a timbre parameter table on the ROM 4 as shown in FIG. Note that the timbre parameters transmitted to the sound source 8 in step S22 are the timbre parameters in a narrow sense excluding the effect number and the effect balance among the timbre parameters Pn (n = 1 to 10).

Next, by referring to the effect number of the tone color parameter Pn corresponding to the tone number selected in step S23, the effect sampling frequency flag of the effect specified by the effect number is read out and transmitted as the selection signal SS. The effect number is defined such that reverb is “1”, chorus is “2”, and so on. The effect sampling frequency flag is stored in the ROM 4 together with each effect program main body, as shown in FIG. Here, the effect sampling frequency flag of the reverb is “1”, and the effect sampling frequency flags of other effects are “0”.

Next, in step S24, the effect program of the effect number is sent to the DSP 203 and loaded. Then, the effect balance of the timbre parameter Pn corresponding to the timbre number selected in step S25 is read, and the multipliers BD1 and BD2 in the multipliers 208 and 209.
Transmitted as D2. Next, after performing other panel processing in step S26, the process returns.

According to the second embodiment, the effect given to the musical tone is determined according to the selected timbre. In addition, since the selection signal SS is determined according to the effect, if a timbre is selected, how to set the sampling frequency when the effect is applied is automatically determined. The addition and change of the tone color and the addition and change of the effect can be easily performed by adding and changing the information of FIGS. 7B and 7C. In the second embodiment, since the effect is determined according to the tone, the effect selecting switch 62 is unnecessary. However, the effect may be switched by pressing the effect selecting switch 62 after selecting the tone.

Next, a third embodiment of the present invention will be described.
The third embodiment has the same configuration as that of the first embodiment shown in FIGS. 1 to 4, and the main routine is the same as that of FIG. 5, so that the description thereof will be omitted. Further, in the third embodiment, the loading of the effect program according to the operation of the effect selection switch 62 by the user is the same as that of the first embodiment shown in FIG.
Description will be made assuming that the processing has been performed in advance in the same manner as (a). That is, it is assumed that the same effect program loading processing as that of FIG. 6A is performed in step S37 in the flowchart of FIG.

In the third embodiment, the degree of the effect to be provided can be changed by using the slider 63. For example, when giving the reverb effect, the reverb time can be changed by operating the slider operator 63. Here, the used capacity of the RAM 205 (FIG. 2) used for the delay processing changes according to the size of the reverb time. Therefore, as can be seen from the following flowchart,
When the operation element output is larger than the predetermined threshold value A, the sampling frequency is reduced to 1/2, and the effect is applied. When the operation element output is equal to or less than the predetermined threshold value A, the effect is applied without changing the sampling frequency. Like that.

Referring to the flowchart of FIG.
In the panel processing routine according to the third embodiment,
First, in step S31, it is determined whether or not there is an operation event of the slider operator 63. If there is no operation event, the process proceeds to step S37. If there is an operation event of the slider operator 63, a threshold value A is read from the effect program corresponding to the effect selected at that time in step S32, and the output of the slider operator 63 and this threshold value are read. Compare with A. The threshold value A is as shown in FIG.
As shown in FIG. 2, the program is stored together with the main body of each effect program on the ROM 4.

In step S32, the output of the operator is set to the threshold value A.
If it is larger, "1" is transmitted as the selection signal SS in step S33. Then, in step S35, half the value of the operation element output is sent to the effect imparting section 9, and in step S3
Go to 7. If the control output is equal to or smaller than the threshold value A in step S32, "0" is transmitted as the selection signal SS in step S34. Then, in step S36, the value of the manipulator output is sent to the effect applying unit 9, and the process proceeds to step S37. After performing other panel processing in step S37, the process returns.

The values sent to the effect applying section 9 in steps S35 and S36 are input to the DSP 203 (not shown), and the DSP 203 determines the degree of effect application based on the input values. For example, to add a reverb effect,
An area for the capacity corresponding to the input value is secured in the RAM 205 and used as a storage area for delay. Therefore, when the sampling frequency is 25 kHz, the same delay time can be obtained with half the capacity as compared with the case where the sampling frequency is 50 kHz. In step S35, half the value of the manipulator output is sent to the effect imparting unit 9. I have to.

According to the third embodiment, the RAM 205 for delay processing can be used effectively. That is, if the above-described threshold value A is appropriately selected, processing is performed at a sampling frequency of 50 kHz until the entire capacity of the RAM 205 is used up, and processing to be performed at a sampling frequency of 25 kHz is to realize a delay time longer than that. In particular, when the RAM 205 is used for both the effect program and the delay storage area, the capacity of the delay storage area increases or decreases according to the capacity of the effect program. The threshold value can be changed according to, and each effect program can be operated effectively.

In the first to third embodiments, for simplicity, the sampling frequency 50 kHz is halved to 25 kHz.
Although an example in which the effect is given by lowering to Hz has been described, the present invention is not limited to this, and processing may be performed by lowering to any sampling frequency. For example, the effect may be given by setting the frequency to n / m of the original sampling frequency. However, in this case, the circuit of the decimation filter and the interpolation filter becomes more complicated than the case where the frequency is set to 1/2, 1/4,. Specifically, the original tone signal is 1 / m
And then oversample by n times. In the interpolation filter, the reverse process is performed.

[0054]

As described above, according to the present invention, the digital musical tone waveform signal of the first sampling frequency can be used as it is or in accordance with the type of the effect selected by the effect selecting means. Since a digital tone waveform signal is converted to give an effect such as reverb, various effects can be given while realizing a longer delay time using a RAM having a smaller capacity.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic musical instrument to which an effect applying device according to an embodiment of the present invention is applied.

FIG. 2 is a detailed block diagram of an effect providing unit.

FIG. 3 is a block diagram of a decimation filter.

FIG. 4 is a block diagram of an interpolation filter.

FIG. 5 is a flowchart of a main routine of the electronic musical instrument according to the embodiment.

FIG. 6 shows a flowchart of a panel processing routine and an effect program.

FIG. 7 is a flowchart showing a panel processing routine, a tone color parameter table, and an effect program according to a second embodiment;

FIG. 8 is a diagram illustrating a flowchart of a panel processing routine and an effect program according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... keyboard, 2 ... keyboard interface, 3 ... random access memory (RAM), 4 ... read-only memory (ROM), 5 ... central processing unit (CPU), 6 ... panel, 7 ... panel interface, 8 ... sound source, 9 ... Effect giving part, 10 ... Sound system, 11 ... Bus line,
61: tone selection switch, 62: effect selection switch, 6
Reference numeral 3 denotes a slider operator, 201 denotes a decimation filter, 202 denotes a selector, 203 denotes a DSP, 204 denotes a selector, 205 denotes a RAM, 206 denotes an interpolation filter, 207 denotes a selector, 208 and 209 denotes a multiplier, and 210 denotes an adder.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-204897 (JP, A) JP-A-4-212996 (JP, A) JP-A-3-256097 (JP, A) JP-A-61- 90514 (JP, A) JP-A-64-68799 (JP, A) JP-A-1-321486 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G10H 1/00-7 / 00 541 G10G 1/02 G10K 15/12

Claims (1)

(57) [Claims] 1. An effect applying apparatus for inputting a digital musical tone waveform signal, applying various effects to the digital musical tone waveform signal, and outputting the digital musical tone waveform signal, selecting an effect to select a first effect or a second effect to be applied to the digital musical tone waveform signal. Means, when the first effect is selected by the effect selecting means, outputs the input digital tone waveform signal of the first sampling frequency without changing, and the second effect is selected by the effect selecting means. Means for converting the input digital tone waveform signal of the first sampling frequency into a digital tone waveform signal of the second sampling frequency and outputting the digital tone waveform signal; and a digital tone waveform output from the sampling frequency changing means. Effect providing means for applying the effect selected by the effect selecting means to the signal and outputting the signal. An effect-imparting device to be characterized.