WO2022049760A1

WO2022049760A1 - Audio signal processing device, audio signal processing method, and program

Info

Publication number: WO2022049760A1
Application number: PCT/JP2020/033743
Authority: WO
Inventors: 健太佐川; 満宣遠藤; 悠佑津田; 伸哉小泉
Original assignee: ＡｌｐｈａＴｈｅｔａ株式会社
Priority date: 2020-09-07
Filing date: 2020-09-07
Publication date: 2022-03-10
Also published as: JP7475465B2; JPWO2022049760A1

Abstract

Provided is an audio signal processing device (100) which comprises: a buffer (114) in which audio signals are temporarily accumulated; a first gate (115A) which is connected to an output side of the buffer (114), turns on when an input to the buffer (114) is substantially off, and turns off otherwise; and a feedback path (117) which is branched from an output side of the first gate (115A) and connected to an adder (116) of an input side of the buffer (114).

Description

Audio signal processing equipment, audio signal processing methods and programs

The present invention relates to an audio signal processing device, an audio signal processing method and a program.

Various technologies for improving functionality and operability have been proposed in audio equipment such as controllers and mixers used for DJ performance. Examples of such techniques are described, for example, in Patent Document 1, Patent Document 2, and Patent Document 3.

International Publication No. 2019/239538 International Publication No. 2019/239486 International Publication No. 2019/234861

Conventional techniques such as those described in the above document implement the ability to play music by adding effects such as delay, echo, reverb, or loop to the music using a buffer that temporarily stores the audio signal. You can add various effects to the music in the performance. However, it may be difficult to appropriately add an effect when, for example, a complicated reproduction operation of a musical piece is performed in a DJ performance, and there is still room for improvement in the effect of a musical piece using a buffer.

Therefore, an object of the present invention is to provide an audio signal processing device, an audio signal processing method, and a program capable of improving the effect added to a music by using a buffer.

[1] The first, which is connected to the buffer in which the audio signal is temporarily stored and the output side of the buffer, is turned on when the input of the buffer is substantially off, and is turned off when the input of the buffer is not substantially turned off. An audio signal processing device including a gate and a feedback path branched from the output side of the first gate and connected to an adder on the input side of the buffer.
[2] The audio signal processing device according to [1], further comprising an attenuator connected between the buffer and the branch point of the feedback path.
[3] The audio signal processing device according to [1], further comprising a variable amplifier connected between the buffer and the branch point of the feedback path.
[4] The audio signal processing device according to any one of [1] to [3], wherein the first gate is switched from off to on by an operation of substantially turning off the input of the buffer.
[5] Further includes a second gate connected to the front stage of the adder, the first gate is turned on when the second gate is off, and is turned off when the second gate is on. The audio signal processing device according to any one of [1] to [3].
[6] A step of temporarily storing the input audio signal in the buffer, a step of outputting the audio signal stored in the buffer when the input of the buffer is substantially off, and a step of feeding back to the buffer, and a buffer. A method of processing an audio signal that includes a step of disabling feedback to the buffer without outputting the audio signal stored in the buffer when the input is not substantially off.
[7] The audio signal processing method according to [6], further comprising a step of amplifying or attenuating the audio signal fed back to the buffer.
[8] A first buffer in which an audio signal is temporarily stored and connected to the output side of the buffer, which is turned on when the input of the buffer is substantially off, and turned off when the input of the buffer is not substantially off. A program for operating a computer as an audio signal processing device including a gate and a feedback path branched from the output side of the first gate and connected to an adder on the input side of the buffer.

According to the above configuration, since the gate is connected between the output side of the buffer and the branch point of the feedback path, no audio signal is input to the feedback path while the gate is off, thereby using the buffer. The effects added to the music can be improved.

It is a figure which shows the whole structure of the mixer which concerns on one Embodiment of this invention. It is a figure which shows the structure of the effect circuit of the mixer shown in FIG. It is a figure which shows the state which the gate is turned off in the effect circuit shown in FIG. It is a figure which shows the state which the gate is turned on in the effect circuit shown in FIG. It is a figure which shows the reference example of an effect circuit. It is a figure which shows the reference example of an effect circuit. It is a figure which shows the structure of the effect circuit in the modification of one Embodiment of this invention.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings below. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a diagram showing an overall configuration of a mixer according to an embodiment of the present invention. The audio signal processing device according to this embodiment is a mixer 100 used for DJ performance. The mixer 100 processes a two-channel audio signal input from an external sound source according to an operation on an operator such as a switch or a knob arranged in a housing, and outputs the signal to a speaker or the like. The controls of the mixer 100 include

channel faders

101A and 101B and a crossfader 102. The

channel faders

101A and 101B are configured so that the volume of the music played in each channel can be gradually changed by sliding in the illustrated directions D1 and D2, and slides to the end of the range of motion in the direction D2. Then, the volume of each channel becomes 0.

On the other hand, the crossfader 102 is configured to adjust the balance of the music played on each channel. When the channel fader 101A side is the A channel and the channel fader 101B side is the B channel, when the crossfader 102 is slid to the end of the direction D3 shown, the volume of the music of the B channel becomes 0 and is slid in the direction D4. And the volume of the music on channel A becomes 0, and in the middle part, the music on both channels is played at a volume other than 0.

Further, the controller of the mixer 100 includes a button 103 for activating the effect function described below. The controls of the mixer 100 including the faders and buttons described above are configured in the same manner as a normal mixer except that they are used for effect functions as described below. Therefore, more details about the controls are provided. The explanation is omitted.

FIG. 2 is a diagram showing the configuration of the effect circuit of the mixer shown in FIG. In the mixer 100, the audio signal processing circuit is implemented by software using a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The illustrated effect circuit 110 is connected to each of the A channel and the B channel of the mixer 100 after the volume adjustment process by the fader. Therefore, the audio signal input to the effect circuit 110 reflects the result of tone adjustment by the

channel faders

101A and 101B and the crossfader 102. Specifically, for example, in a state where the

channel faders

101A and 101B are slid to the end of the direction D2 shown in FIG. 1, an audio signal (no signal) having a volume of 0 is input to each channel, and the crossfader 102 is used. In the state of sliding to any end of the directions D3 and D4, an audio signal (no signal) having a volume of 0 is input in any of the channels. Hereinafter, the configuration of each part of the effect circuit 110 will be further described.

The effect circuit 110 includes

transmission paths

111A and 111B connected in parallel. The transmission path 111A is a bypass path, and an audio signal of the original sound to which no effect is applied is transmitted. The transmission path 111B includes a circuit configuration for an effect as described later, and an audio signal of the effect sound is transmitted. The balance between the original sound and the effect sound is adjusted by the

amplifiers

112A and 112B, and is added to each other by the adder 113 and output. A buffer 114 is connected to the transmission path 111B. The buffer 114 temporarily stores the input audio signal and outputs it after a predetermined delay time. A gate 115A is connected to the output side of the buffer 114. As used herein, a gate means a circuit element (implemented software as described above) configured to transmit a signal when it is on and to block the signal when it is off. do. Gate 115A is turned on if the input to buffer 114 is substantially off, and turned off otherwise.

More specifically, the effect function is enabled by the operation of the button 103 shown in FIG. 1, and the

channel faders

101A and 101B are slid to the end of the direction D2 shown in FIG. 1 or crossed. When the fader 102 is slid to any end of the directions D3 and D4, the gate 115A is turned on in the effect circuit 110 of the channel where the input becomes an audio signal (no signal) with a volume of 0. That is, in the example of FIG. 2, the gate 115A is switched from off to on by an operation of substantially turning off the input of the buffer 114. Since the effect sound is output when the gate 115A is turned on as described later, the operation of the

channel faders

101A, 101B or the crossfader 102 as described above is an effect trigger operation.

Further, in the transmission path 111B, a feedback path 117 that branches from the output side of the gate 115A and is connected to the adder 116 on the input side of the buffer 114 is connected. Further, a variable amplifier 118 may be connected between the buffer 114 and the branch point of the feedback path 117, more specifically, between the buffer 114 and the gate 115A. In another example, an attenuator may be connected instead of the variable amplifier 118. While the gate 115A is on, the audio signal stored in the buffer 114 is output as an effect sound through the adder 113 and is fed back to the buffer 114 via the feedback path 117 after a predetermined delay time. It is played repeatedly. When the amplification factor is less than 1 in the variable amplifier 118 and when an attenuator is connected, the effect sound that is repeatedly reproduced is gradually attenuated (fade out). On the contrary, when the amplification factor exceeds 1 in the variable amplifier 118, the effect sound is gradually amplified (fade in). If there is no variable amplifier 118 or the amplification factor is 1, the effect sound continues to be played repeatedly at the same volume (loop).

FIG. 3 is a diagram showing a state in which the gate is turned off in the effect circuit shown in FIG. When the input to the buffer 114 is not substantially off in the effect circuit 110 and therefore the gate 115A is off, the input audio signal is temporarily stored in the buffer 114, but the output of the buffer 114 is output. Since it is blocked by the gate 115A, the audio signal stored in the buffer 114 is not output. Further, since the feedback path 117 is branched from the output side of the gate 115A as described above, the feedback of the audio signal to the buffer 114 by the feedback path 117 is invalidated while the gate 115A is off, and the buffer 114 is provided with the feedback path 117. Only the audio signals for the latest delay time are sequentially accumulated.

FIG. 4 is a diagram showing a state in which the gate is turned on in the effect circuit shown in FIG. Since the gate 115A is turned on in the effect circuit 110 when the input of the buffer 114 is substantially off, the audio signal (no signal) at volume 0 is input to the effect circuit 110 in the illustrated state. ). On the other hand, the audio signal input immediately before the input is substantially turned off is stored in the buffer 114, and the audio signal stored in the buffer 114 has a predetermined delay time while the gate 115A is on. It will be output later. In addition, while the gate 115A is on, the audio signal stored in the buffer 114 is fed back to the buffer 114 via the feedback path 117. At this time, for example, the audio signal fed back by the variable amplifier 118 may be amplified or attenuated. In this way, when the gate 115A is turned on, the audio signal stored in the buffer 114 is output, added to the audio signal of the original sound by the adder 113 as an effect sound, and repeatedly reproduced by feedback. .. Since the original sound has no signal as described above, only the audio signal of the effect sound that is repeatedly reproduced is output from the effect circuit 110. For example, by setting the amplification factor by the variable amplifier 118 as described above, it is possible to add a kind of effect called delay, echo, reverb, loop, or the like to the music by this effect sound.

5 and 6 are diagrams showing a reference example of the effect circuit. As shown in FIG. 5, the difference between the effect circuit 910 according to the reference example and the effect circuit 110 shown in FIG. 2 above is that in the effect circuit 910, between the output side of the buffer 114 and the branch point of the feedback path 117. The gate 115A is not connected to the gate 115A, but instead the gate 915 is connected after the branch point of the feedback path 117 (on the adder 113 side). As shown in FIG. 6, when the gate 915 is off, the output of the buffer 114 is cut off by the gate 915, so that the effect sound is not added to the original sound by the adder 113, which is the same in the reference example. However, in the reference example, since the feedback path 117 branches from the input side of the gate 915, the audio signal is fed back through the feedback path 117 even when the gate 915 is off, and the audio for the latest delay time is fed back to the buffer 114. In addition to the signal, the repeated reproduction of the previous audio signal is accumulated in a superimposed manner.

As a result of the above configuration, in the reference example, when the original sound input to the effect circuit 910 becomes no signal and the gate 915 is turned on, the original sound is input to the buffer 114 just before the original sound becomes no signal. Not only the audio signal, but also the repeated reproduction of the previous audio signal is accumulated in a superimposed manner. For example, depending on the setting of the amplification factor by the variable amplifier 118 as described above, the sound reproduced by the superimposed audio signal may be perceived as the muddyness of the effect sound. Further, when the trigger operation of the effect is repeated in a short time, for example, when the operation of the crossfader 102 is repeated while scratching in the DJ performance, the previous trigger operation is performed in the buffer 114 at the time of the second and subsequent trigger operations. It may be difficult to properly add an effect due to the overlapping of non-continuous music sounds in the effect sound because the audio signal for the repeated playback of the time remains.

In the effect circuit 110 of the mixer 100 according to the present embodiment, by connecting the gate 115A between the output side of the buffer 114 and the branch point of the feedback path 117 as described above, feedback is provided while the gate 115A is off. The feedback is disabled via the path 117, thereby avoiding the muddy sound and the problems that may occur when the trigger operation is repeated as in the case of the reference example. In addition to such a problem, for example, the delay time of the buffer 114 is set to be long, the amplification factor of the variable amplifier 118 is set to a value close to 1, and the music for the delay time of the buffer 114 is set by the first trigger operation. By continuously turning off and on the trigger operation of the effect in a time shorter than the delay time while looping the section of the loop playback, only a part of the loop playback is played in another section (or another section) of the music. It is also possible to perform new performances such as replacing with the sound of the section of the music.

FIG. 7 is a diagram showing a configuration of an effect circuit in a modified example of the embodiment of the present invention. The effect circuit 110A according to the modified example is connected to the front stage of the adder 116 which is a connection point of the feedback path in the transmission path 111B in addition to the same components as the effect circuit 110 described with reference to FIG. Includes gate 115B. In this example, the gate 115A connected to the output side of the buffer 114 is turned on when the gate 115B is off and turned off when the gate 115B is on. Here, in the example of FIG. 2, the operation in which the input of the effect circuit 110 becomes an audio signal (no signal) at volume 0 becomes the trigger operation of the effect, so that the input of the buffer 114 of the gate 115A is substantially turned off. The behavior is realized that it turns on in some cases and turns off in other cases. On the other hand, the gate 115B in the example of FIG. 7 realizes the same operation regardless of the type of trigger operation of the effect. That is, for example, even if any button or switch of the mixer 100 is used to trigger the effect and the input of the effect circuit 110 does not necessarily become an audio signal (no signal) at volume 0 during the trigger operation, the trigger operation is performed. By turning off the gate 115B at the same time that the gate 115A is turned on, the same operation as described above with reference to FIG. 4 is realized.

The audio signal processing device having the above functions is not limited to the mixer described as one embodiment, and may be, for example, a DJ controller having a mixer function. In the above example, a 2-channel mixer has been described, but a similar function can be realized with a 4-channel mixer, for example. Further, the present invention is not limited to DJ equipment, and can be applied to audio equipment such as general mixers and electronic musical instruments.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. It is naturally understood that these also belong to the technical scope of the present invention.

100 ... Mixer, 101A, 101B ... Channel fader, 102 ... Crossfader, 103 ... Button, 110, 110A ... Effect circuit, 111A, 111B ... Transmission path, 112A, 112B ... Amplifier, 113 ... Adder, 114 ... Buffer, 115A , 115B ... Gate, 116 ... Adder, 117 ... Feedback path, 118 ... Variable amplifier, D1, D2, D3, D4 ... Direction.

Claims

A buffer in which audio signals are temporarily stored, and
A first gate that is connected to the output side of the buffer and is turned on if the input to the buffer is substantially off, and turned off otherwise.
An audio signal processing device including a feedback path that branches from the output side of the first gate and is connected to an adder on the input side of the buffer.
The audio signal processing device according to claim 1, further comprising an attenuator connected between the buffer and the branch point of the feedback path.
The audio signal processing device according to claim 1, further comprising a variable amplifier connected between the buffer and the branch point of the feedback path.
The audio signal processing device according to any one of claims 1 to 3, wherein the first gate is switched from off to on by an operation of substantially turning off the input of the buffer.
A second gate connected to the front stage of the adder is further provided.
The first gate is turned on when the second gate is off, and is turned off when the second gate is on, according to any one of claims 1 to 3. The audio signal processing device described.
A step to temporarily store the input audio signal in the buffer,
A step of outputting an audio signal stored in the buffer and feeding it back to the buffer when the input of the buffer is substantially off.
A method of processing an audio signal including a step of not outputting an audio signal stored in the buffer and disabling feedback to the buffer when the input of the buffer is not substantially off.
The audio signal processing method according to claim 6, further comprising a step of amplifying or attenuating the audio signal fed back to the buffer.
A buffer in which audio signals are temporarily stored, and
A first gate that is connected to the output side of the buffer and is turned on if the input to the buffer is substantially off, and turned off otherwise.
A program for operating a computer as an audio signal processing device including a feedback path that branches from the output side of the first gate and is connected to an adder on the input side of the buffer.