JPH02114297A - Effect device - Google Patents

Abstract

PURPOSE:To remove a click noise by gradually switching a delay length in a comparatively small unit from the delay length before the change to the delay length after the change when the delay length is to be changed. CONSTITUTION:Even when the change of the delay length in a digital memory 12 as a variable delay means is instructed, offset data to set the delay length after the change are never directly inputted to a computing element 31. Namely, the offset data are inputted to the computing element 31 after the offset data are processed so as to gradually change from the offset data to set the delay length before the change through a comparator 32 and an offset data counter 30. Consequently, even when the phase of a delay output signal corresponding to the delay length before the change does not coincide with the phase of another delay output signal corresponding to the delay length after the change, the read address of the digital memory 12 gradually changes from an address corresponding to the delay length before the change to another address corresponding to the delay length after the change, and the phase changes smoothly. Thus, the click noise can be removed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention has an effect of 9 m used in electronic musical instruments, etc.
In particular, the present invention relates to eliminating click noise that occurs when switching the delay length in a device that imparts a predetermined effect based on delaying a musical tone signal.

[Conventional technology]

In effect devices used in electronic musical instruments,
There are devices that use digital delay devices to add modulation effects such as "delay,""reverb,""phaser,""vibrato," and "tremolo" (for example,
JP-A-58-14191, JP-A-58-1/1898
No., JP-A-58-50595, JP-A-58-1085
No. 83, etc.).

[Problem to be solved by the invention]

The delay length in a digital delay device may be changed automatically depending on the performer's operation or in response to a program, etc., during the process of processing the signal of the instrument. , due to the phase discontinuity between the delay output No. 49 before the change and the delay ratio Chi, No. 4 after the change,
There was an inconvenience that click noise occurred at the switching part. Particularly, in the case of an effect such as reverb, in which a delayed output signal is fed back to the input side of a delay device, one problem is serious because the rick noise is circulated in this way.

The present invention aims to provide an effective device capable of removing such click noise.

[Means to solve the problem]

The present invention provides an effect device which outputs inputted musical tone No. 43 with a delay and is provided with a variable delay means capable of switching the delay length, and which imparts an effect based on this delay to the musical tone signal. This problem occurs when the delay length of a means should be changed, using a delay length switching means that gradually changes the delay length from the pre-change delay length to the post-change delay length in relatively small units. It is characterized by eliminating click noise.

[Effect]

When the delay extension is to be changed, the delay length is gradually switched from the pre-change delay length to the post-change delay length in relatively small units. Therefore, the delay length in the variable delay means does not suddenly change from the delay length before change to the delay length after change, but gradually slides in relatively small units. As a result, even if the phase of the output signal of the variable delay means corresponding to the delay length before change and the phase of the output signal of the variable delay means corresponding to the delay length after change are discontinuous, the delay length can be gradually changed. As a result, the phase of the output signal of the variable delay means changes relatively smoothly and continuously, making it possible to eliminate click noise.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, a musical tone signal corresponding to a key suppressed on a six-key keyboard 10 is digitally generated by a musical tone signal generating circuit 11, which shows an embodiment applied to a reverb effect device for an electronic musical instrument.
generated from.

The digital memory 1.2 consisting of a RAM corresponds to a variable delay device, and the digital musical tone signal DO5 generated from the musical tone signal generating circuit 11 is transmitted to the digital memory 12 via an adder 13 and a multiplier 14. Applied to data input IN.

The output OUT of the digital memory 12 corresponds to the delayed output of the variable delay device, and this delayed output is given to the adder 13 via the multiplier 15 and fed back to the input side of the variable delay device δ. Further, the delayed output is applied to the adder 19 via the multiplier iLy I G, and is added to the input musical tone signal applied to the adder 19 via the 9-multiplier 17. The output of the adder 19 is latched in an output register 20, and further input as a digital musical tone signal with a reverb effect to a digital/analog converter 21, where it is analog-converted and then sent to a sound system 22. Multiplier 14
Parameters C1 to C4 for setting the reverb effect are given to the coefficient inputs 17 to 17.

The timing signal generation circuit 23 is connected to the digital memory 12
Generates a signal R/WS that controls reading and writing of the data. A sampling clock pulse SCK is generated from the musical tone signal generating port '811 in synchronization with the sampling period of the digital musical tone signal DO3, and is applied to the timing signal generating circuit 23. Based on the sampling clock pulse SCK and the system clock pulse φ, the timing signal generating circuit 23 generates a read/write control signal R/WS that instructs writing in the first half period of the sampling period and instructs reading in the latter half period. In addition, the i-th SL is generated during the last 174 periods of the sampling period. An example of the timing chart 1 of these pulses is shown in FIG.

The read/write control signal R/WS is applied to the read/write control input R/W of the digital memory 12, and as described above, the digital musical tone signal samples added to the data input IN during the first half period of one sampling period of the digital musical tone signal DO8. The write address and read address at which value data is written and read in the second half period are specified by data applied from the selector 24 to the address input AD of the digital memory 12. The take-in signal SL is applied to the take-in control input of the output register 20, and the digital musical tone signal data for one sample point, on which the effect has been calculated, given from the adder 19, is taken into the output register 20.

The address counter 25 sequentially counts the sampling clock pulses SCK.

Create write address data. The count output of the address counter 25 is applied to the selector 24, and when the read/write control signal R/WS is 11011, that is, in the write mode in the first half of the sampling period, the selector 24 selects the digital memory. 1
2 address input AD as write addressing data.

Therefore, the sample value data of the input digital tone signal is stored in the digital memory 12 in accordance with its time order.
are written to sequential addresses in order.

In the digital memory 12, the read address of the digital musical tone signals written in order in the addresses in this way is shifted (offset) from the write address.
Therefore, the offset data for performing a delay according to the address location of the offseter 1 is given from the offsetler 1 to the data counter 30.

The effect selector 27 is for selecting a reverb effect, and the coefficient generation circuit 28 generates coefficients 01 to C4 according to the reverb effect selected here, and the coefficients 01 to C4 are generated by the multiplier 1.
Give from 4 to 17. Further, the delay length setting section 29 generates data instructing the delay length in accordance with the selected reverb effect. The offset data generation circuit 26 generates offset data according to the delay length specified by the delay length setting section 29. Note that the delay length setting section 29 may be a manually operated delay length setting device that is not linked to the effect selector 27.

The offset data generated from the offset data generation circuit 26 is applied to the comparator 32. Comparator 3
The output of Offcella 1-data counter 30 is given to the B input of No. 2. The comparator 32 compares the eight force and the B input, and if A=B, outputs a signal "1" to the "rA=B" output,
Otherwise output '0'', if A>B then rA>B
J high output signal II I Outputs H, otherwise H
Output OII. The rA=BJ output is inverted by an inverter 33 and applied to the count clock input CLK of the offsetler 1-data counter 30 via an AND circuit 34. A sampling clock pulse SCK is applied to the other input of the AND circuit 34. comparison)! :÷32 rA
>BJ high output offset data counter 30 up/
The down count control is given to the human power U/D.

The output of the offset data counter 30 is input to the comparator 32 as described above, and is also provided to the arithmetic unit 31.

Operation 3\'a: + 31's other manual input is the callan 1-data of the address counter 25.9For example, by subtracting the offset data from this count data, the calculation result is ? Create d'l output address data. The read address data output from the arithmetic unit 31 is given to eight inputs of the selector 24, and the read/write control (when the R number R/WS is '1'', that is, in the read mode in the latter half of the sampling period), the selector 24 is selected and applied to the address input AD of the digital memory 12 as read address designation data.

When the delay length specified by the delay length setting unit 29 is changed,
Although the offset data generated from the offset data generating circuit 26 is changed, the modified offset data is directly transmitted to the arithmetic unit 31. The data is not provided to the memory 12 via the selector 24 but via the offset data counter 30.

This point will be explained with reference to FIG.
The data corresponds to the delay length after the change, and the count data output from the offset data counter 30, that is, the offset data that sets the actual delay length, corresponds to the delay length before the change. When the delay length after the change is longer than the delay length before the change, A>B holds true in the comparator 32,
"When Δ>BJ high output II II II, the offset data counter 30 goes into up-count mode, and...

Since the rA=BJ output is I'O'1 and the AND circuit 34 is enabled, the offset data counter 30 counts up the sampling clock pulse SCK.

As a result, the count data output from the offset data counter 30, that is, the offset data that sets the actual delay length, gradually increases from a value corresponding to the delay length before the change to a value corresponding to the delay length after the change. . When the output of the offset data counter 30 matches the value corresponding to the changed delay length, A=B holds true in the comparator 32, and r
The A=BJ output becomes 111", the AND circuit 34 is disabled, and the offset data counter 30's output is 111".
stops. As a result, the output of the offset j-data counter 30, that is, the offset data that sets the actual delay length, maintains the value corresponding to the changed delay length. On the other hand, when the delay length after the change is smaller than the delay length before the change, A>B does not hold in the comparator 32, the rA>BJ output is II O++, and the offset data counter 30 is in down count mode. and rA=BJ output is II
Since the AND circuit 34 is enabled in O++.

The offset data counter 30 counts down the sampling clock pulse SCK. As a result, the count data output from the offset data counter 30, that is, the offset data that sets the actual delay length, gradually decreases from a value corresponding to the delay length before the change to a value corresponding to the delay length after the change. .

In this way, even if it is instructed that the delay length in the digital memory 12, which is the variable delay means, should be changed,
Offset 1 data for setting the changed delay length is not directly input to the calculator 31, and is compared with: ÷32. Offset 1-
The offset data that sets the delay length before the change is processed through the data counter 30 so that it changes gradually, and then input. As a result, even if the phase of the delayed output signal corresponding to the delay length before the change does not match the phase of the delayed output signal corresponding to the delay length after the change, the read address of the digital memory 12 will be the same as before the change. Since the phase changes gradually from the address corresponding to the delay length to the address corresponding to the changed delay length so that the phase changes smoothly, click noise can be removed.

Note that the pulse input to the offset data counter as the count clock pulse CLK is not limited to the sampling clock pulse SCK, but may be a signal obtained by dividing the sampling clock pulse SCK as appropriate, or a pulse generated by another independent clock pulse generation circuit. Good too. Preferably, it is advantageous to use a pulse slower than the sampling glock pulse SCK because clicks will be less likely to occur.

In addition, in the above embodiment, the +)′L delay length when gradually changing from the value corresponding to the delay length before change to the value corresponding to the delay length after change, the minimum unit, that is, one address unit. However, the present invention is not limited to this, and the delay length corresponding to two or more addresses may be changed gradually by one unit (however, it is a relatively small unit that can prevent clicks).

The above embodiment is an example in which the present invention is applied to a reverb effect device, but the present invention is not limited to this, and variable delay devices such as "delay", "phaser", "vibrato", and "1-remolo J young fruit" are used. The present invention can be applied to an effect device.

Further, the effect device of the present invention is not limited to a built-in electronic musical instrument type, but may be a stand-alone device.

〔Effect of the invention〕

As described above, according to the present invention, when the delay length should be changed, the delay length is gradually switched from the delay length before the change to the delay length after the change in relatively small units. Even if the phase of the output signal of the variable delay means corresponding to the delay length and the phase of the output signal of the variable delay means corresponding to the changed delay length are discontinuous, the variable delay means The phase of the output signal changes relatively smoothly and continuously, and click noise can be removed, which is an excellent effect.

[Brief explanation of the drawing]

1 is a block diagram showing an embodiment of an electronic musical instrument to which an effect device according to the present invention is applied; FIG. 2 is a timing chart 1 to 3 showing an example of read/write control timing of the digital memory in FIG. 1; is a timing chart 1-1 showing an example of the counting operation of the offset data counter in FIG. 1 when the delay length is changed. 10... Keyboard, 11... Musical tone signal generation circuit, 12.
... Digital memory, 14-17 ... Multiplier, 26
. . . Offset data generation circuit, 29 . . . Delay length setting section. 30...Offset data counter, 32...Comparator. Patent applicant Yamaha Co., Ltd. Agent

Claims (1)

[Scope of Claims] An effect device comprising variable delay means capable of delaying and outputting an input musical tone signal and switching the delay length, and imparting an effect based on the delay to the musical tone signal, comprising: When the delay length of the means should be changed, the delay length switching means gradually changes the delay length from the delay length before the change to the delay length after the change in relatively small units,
An effect device characterized by eliminating click noise that occurs when changing a delay length.