JPH11150785A - Microphone level controller and karaoke system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent level fluctuations of all microphone outputs caused by an increase/decrease of an echo level. SOLUTION: A microphone signal is passed through a volume 16 for microphone level control and branched to a signal path 18 for echo signal generation and a signal path 20 for direct sound. The microphone signal branched to the signal path 18 for echo signal generation is inputted through the volume 16 for echo level control to a delay circuit 24, and the echo signal is generated. A synthesizer circuit 26 adds, synthesizes and outputs the direct sound signal and the microphone signal. When a microphone level control manipulator 36 is manipulated, a microcomputer 54 controls the volume 16 and changes all the microphone outputs. When an echo level control manipulator 38 is manipulated, the microcomputer 54 controls a volume 22, changes the level of the echo signal, controls the volume 16 backward and suppresses fluctuations of all microphone output levels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting a microphone level and a karaoke apparatus using the same, in which the fluctuation in the level of the entire output of the microphone due to the increase or decrease in the echo level is prevented.

[0002]

2. Description of the Related Art FIG. 2 shows a signal system of a conventional karaoke apparatus. The microphone signal output from the microphone 10 is input from the microphone signal input terminal 12, and the level is adjusted by a volume (attenuator) 16 via a head amplifier 14.
The level-adjusted microphone signal is branched into an echo signal generation signal path 18 and a direct sound signal path 20. The microphone signal branched to the echo signal generation signal path 18 is further level-adjusted by a volume (attenuator) 22,
The signal is input to the delay circuit 24 to generate an echo signal. The synthesis circuit 26 adds and synthesizes a microphone signal (direct sound signal) to which no echo is applied and an echo signal.

[0003] All the microphone signals output from the synthesizing circuit 26 are added and synthesized with a music signal (accompaniment sound signal) in a synthesizing circuit 28, the level is adjusted by a volume (attenuator) 30, and then amplified by an amplifier 32. The sound is reproduced from the speaker 34.

[0004] A microphone level adjusting operation element 36 is used for adjusting the microphone level. Here, the microphone level adjustment operation element 36 is used to variably operate the volume 16, and by operating the operation element 36, it branches into the echo signal generation signal path 18 and the direct sound signal path 20. The level of the previous microphone signal is variably adjusted, and as a result, the level of the direct sound signal and the level of the echo signal are increased or decreased to an arbitrary value while maintaining a constant ratio.

[0005] The echo level adjusting operator 38 is used for adjusting the echo level. Here, the echo level adjustment operator 38 is used to variably operate the volume 22. By operating the operator 38, the level of the microphone signal branched to the echo signal generation path 18 is variably adjusted. As a result, the level of the echo signal is increased or decreased to an arbitrary value independently of the level of the direct sound signal.
The main level adjustment operator 40 is for adjusting the total output level of the music signal and the microphone signal. Here, the main level adjustment operator 40 is used to variably operate the volume 30,
By operating, the level of all output signals (the sum signal of the music signal and all microphone signals) is increased or decreased to an arbitrary value.

[0006]

According to the signal system shown in FIG. 2, when the echo level is changed by operating the echo level adjusting operator 38, the levels of all microphone signals output from the synthesizing circuit 26 fluctuate. Thus, the balance with the level of the music signal is lost. For this reason, in order to return to the original balance, the microphone level must be adjusted again by the microphone level adjustment operator 36, and the operation is troublesome.

An object of the present invention is to provide a microphone level adjusting apparatus and a karaoke apparatus which solve the above-mentioned problems in the prior art and prevent the fluctuation of the level of all microphone signals due to the increase and decrease of the echo level.

[0008]

A microphone level adjusting apparatus according to the present invention includes a microphone signal input terminal for inputting a microphone signal, and an echo signal generating circuit for generating an echo signal of the microphone signal input from the microphone signal input terminal. A synthesizing circuit for synthesizing the echo signal with the direct sound signal having no echo added to the microphone signal, a microphone level adjusting operator for adjusting the microphone level, and an echo level for adjusting the echo level When the adjustment operator and the microphone level adjustment operator are adjusted, the level adjustment value of the direct sound signal is increased or decreased in accordance with this operation, and the level adjustment value of the echo signal is similarly increased or decreased. And when the echo level adjusting operation is operated, the level adjustment value of the echo signal is increased in accordance with the operation. Others are made of and and a level adjusting circuit for adjusting the level adjustment values of the direct sound signal and the echo signal to reduce or increase the level adjustment values of the direct sound signal with reduced reversed, respectively.

According to this, when the level of the echo signal is changed by operating the echo level adjusting operator, the level of the direct sound signal is automatically changed in the reverse direction, so that the fluctuation of the level of all microphone signals is reduced. Is suppressed. In particular, when the echo level adjustment operator is adjusted, the level adjustment value of the echo signal is adjusted so that the sum of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is substantially maintained at the value before the operation. By adjusting the level adjustment value of the direct sound signal accordingly, the level fluctuation of all microphone signals is almost completely prevented.

As the volume for adjusting the level of the direct sound signal or the echo signal, any of a mechanical volume and an electronically controlled volume (a voltage controlled volume, a digital bow rim, etc.) can be used. In the case of using an electronically controlled volume, the level adjustment circuit includes, for example, an electronically controlled volume that variably adjusts the level adjustment value of the direct sound signal and the echo signal at an arbitrary level ratio, a microphone level adjustment operator, and an echo level. An operation value detection section for detecting the operation value of each of the adjustment operation elements, and a control circuit for adjusting and controlling the electronically controlled volume based on the detection information of these operation value detection sections can be provided. In this case, when, for example, the microphone level adjusting operation is operated, the control circuit keeps the ratio of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal substantially at the value before the operation. The level adjustment values of the direct sound signal and the echo signal are adjusted respectively, and when the echo level adjustment operator is operated, the sum of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is set to the value before the operation. The level adjustment values of the direct sound signal and the echo signal can be adjusted while maintaining substantially the same.

More specifically, the control circuit stores the operation values of the microphone level adjustment operator and the echo level adjustment operator immediately before the operation when the echo level adjustment operator is adjusted, and The sum of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is obtained from these operation values, and the level adjustment value of the echo signal is changed to a value corresponding to the operation value after the adjustment operation of the echo level adjustment operator, The level adjustment value of the direct sound signal may be changed to a value such that the sum of the level adjustment value of the echo signal and the level adjustment value of the echo signal is substantially equal to the obtained value.

The electronically controlled volume is, for example, a first electronically controlled volume arranged on the signal line of the direct sound signal before branching to the echo signal generation circuit, and the electronically controlled volume after branching to the echo signal generation circuit. And a second electronically controlled volume disposed on the input side of the echo signal generation circuit. At this time, when the microphone level adjustment operation member is operated, the second electronically controlled volume is controlled. When the level adjustment value of the volume is fixed, the first electronically controlled volume is adjusted in a corresponding direction, and when the echo level adjusting operation is operated, the second electronically controlled volume is adjusted in the corresponding direction. The first volume may be adjusted in the opposite direction with an adjustment amount substantially half that of the second electronically controlled volume.

Also, a karaoke apparatus according to the present invention, a microphone level adjusting apparatus according to the present invention, a second synthesizing circuit for synthesizing an output signal of the synthesizing circuit and a separately input music signal, and a second synthesizing circuit for this A main level adjustment operator for adjusting the level of the output signal of the circuit, and an output level for increasing or decreasing the level adjustment value of the output signal of the second synthesis circuit in accordance with the adjustment operation of the main level adjustment operator It comprises an adjustment circuit, an amplifier for amplifying the composite signal output from the output level adjustment circuit, and a speaker for reproducing the amplified composite signal. According to this karaoke apparatus, when the echo level is changed, the balance between all the microphone signals and the music signal is suppressed from being lost, and the readjustment operation of the microphone level adjustment operator can be made unnecessary.

[0014]

(Embodiment 1) An embodiment of the present invention in which the levels of direct sound signals and echo signals are adjusted by an electronically controlled volume will be described. FIG. 1 shows the signal system. Microphone signal input terminal 1
The portion from 2 to the synthesizing circuit 26 constitutes the microphone level adjusting device 42, and the whole constitutes the karaoke device 44. The portion surrounded by the dotted line forms the level adjustment circuit 46.

The microphone signal output from the microphone 10 is input from the microphone signal input terminal 12 and
The level is adjusted by a volume (attenuator) 16 via the. The level-adjusted microphone signal is branched into an echo signal generation signal path 18 and a direct sound signal path 20. The microphone signal branched to the echo signal generation signal path 18 is
After the level is further adjusted by a volume (attenuator) 22, the signal is input to a delay circuit 24 (an analog delay circuit or a digital delay circuit) to generate an echo signal. The synthesis circuit 26 adds and synthesizes a microphone signal (direct sound signal) to which no echo is applied and an echo signal.

All the microphone signals output from the synthesizing circuit 26 are added and synthesized with the music signal (accompaniment sound signal) in the synthesizing circuit 28, the level is adjusted by a volume (attenuator) 30, and then amplified by an amplifier 32. The sound is reproduced from the speaker 34.

The volumes 16, 22, and 30 are composed of electronically controlled volumes such as a voltage controlled volume and a digital volume. In the case of using a digital volume, the microphone signal and the music signal are A / D converted and input, and D / A converted after the volume 30. The microphone level adjustment operator 36 is used for adjusting the microphone level.
The operation value is detected by the operation value detection unit 48. The echo level adjustment operator 38 performs an operation of adjusting the microphone level, and the operation value is detected by the operation value detection unit 50. The main level adjustment operator 40 performs an adjustment operation of all output signals (addition signal of a music signal and all microphone signals), and the operation value is detected by an operation value detection unit 52.

Each of the level adjustment operators 36, 38, 40
When the object to be operated by the level adjustment operators 36, 38 and 40 is constituted by a variable resistor, the rotation connected to its movable part (rotary shaft in the case of a rotary type, movable body in the case of a direct drive type). When the object to be operated is constituted by a rotary encoder, it is constituted as a rotary operation knob connected to its rotary shaft, and the object to be operated is constituted by an up / down key switch. In this case, it can be configured as the operation push button. Each of the operation value detection units 48, 50, and 52 includes a level adjustment operator 36,
When the object to be operated by 38, 40 is a rotary encoder or an up / down key switch, it is constituted by a counter or the like in the microcomputer 54, and the object to be operated by the level adjusting operators 36, 38, 40 is an analog system such as a variable resistor. In the case of (1), an A / D converter in the microcomputer 54 or the like can be used.

The microcomputer 54 (control circuit) controls the volume 16, based on the detection information of the operation value detectors 48, 50, 52.
The gains 22 and 30 are adjusted and controlled. That is, when the microphone level adjustment operation element 36 is operated, the volume 16
Is adjusted and controlled to a gain (level adjustment value) corresponding to the operation value (volumes 22 and 30 are fixed). Thus, the levels of the direct sound signal and the echo signal are adjusted while maintaining the ratio between the level adjustment value of the direct sound signal and the level adjustment value of the echo signal at the value before the operation. When the echo level adjusting operation element 38 is operated, the volume 22 is adjusted and controlled to a gain (level adjustment value) corresponding to the operation value, and the sum of the level adjustment values of the volumes 16 and 22 is adjusted before the operation. The gain of the volume 16 is adjusted and controlled in the opposite direction so as to maintain the state (1) (the volume 30 is fixed). When the main level adjustment operation element 40 is operated, the volume 30 is adjusted and controlled to a gain (level adjustment value) corresponding to the operation value (the volumes 16 and 22 are fixed).

FIG. 3 shows a flowchart of the control of the adjustment of the volumes 16 and 22 by the microcomputer 54 when the echo level adjusting operator 38 is operated. The microcomputer 54 stores information on the latest operation values of the microphone level adjustment operator 36 and the echo level adjustment operator 38 detected by the operation value detectors 48 and 50 in the internal RAM (S1). Further, based on the information of the stored latest operation values, the sum of the level adjustment values of the volumes 16 and 22 is calculated, and the internal R value is calculated.
It is stored in the AM (S2). When it is detected that the operation value has been changed by operating the echo level adjustment operation element 38 (S3), when the level adjustment value of the volume 22 is changed to a corresponding value, the sum of the level adjustment values of the volumes 16 and 22 is obtained. An increase / decrease amount of the level adjustment value of the volume 16 for maintaining the value before the change is calculated (S4). And volume 2
In addition to changing the level adjustment value of No. 2 to the value specified by the echo level adjustment operator 38, the level adjustment value of the volume 16 is changed by the calculated increase / decrease amount.

FIG. 4 shows the relationship between the level adjustment value of the volume 22 and the level adjustment value of the volume 16 according to the control flow of FIG. According to FIG. 4, when the volume 22 is adjusted, the volume 16 is adjusted in the opposite direction by a level adjustment amount that is half of the fluctuation amount. For example, if the level adjustment amount of the volume 22 is increased by +6 dB by operating the echo level adjustment operator 38 in the level increasing direction, the level adjustment amount of the volume 16 is decreased by -3 dB. As a result, the level of the echo signal increases by a total of (+6 dB) + (− 3 dB), the direct sound signal decreases by −3 dB, and the increase / decrease amount of all microphone signals becomes (+3 dB) + (− 3 dB) = 0 dB. Become.
As a result, the level of the echo signal can be increased by +3 dB without changing the levels of all microphone signals. That is, the level of the echo signal is +6 with respect to the direct sound.
dB can be increased.

Second Embodiment In the first embodiment, one microphone is used. However, when a plurality of microphones can be connected, the microphone is configured as shown in FIG. 5, for example. This is such that the levels of the microphone signals of the two microphones 10-1 and 10-2 are adjusted by a common microphone level adjustment operation member 16. Microphone signals output from the microphones 10-1 and 10-2 are input from the microphone signal input terminals 12-1 and 12-2, and are supplied to the head amplifiers 14-1 and 14-2 and the resistor 56.
Addition and synthesis are performed at an addition point 58 via -1 and 56-2.
The level of the added and synthesized microphone signal is adjusted by the regulators 16 and 22. Volumes 16 and 22 by microcomputer 54
Is the same as the control (FIGS. 3 and 4) in the first embodiment (FIG. 1).

(Embodiment 3) The embodiment of FIG.
Connect the microphones 10-1, 10-2, 10-3
Set the microphone level to individual volume 16-1, 16-2, 1
The adjustment can be made independently in 6-3. Microphone signals output from the microphones 10-1, 10-2, 10-3 are input to microphone signal input terminals 12-1, 12-2, 12-.
3 and the head amplifiers 14-1, 14-2, 1
Volumes 16-1, 16-2, 16-3 via 4-3
The level is adjusted with. The level-adjusted microphone signals are added and synthesized by the synthesis circuit 60. The microphone level adjustment operators 36-1, 36-2, 36-3 are connected to the microphones 10-
1, 10-2 and 10-3, respectively, and these microphone level adjustment operators 36-1 and 36-
In accordance with the operation of 2, 36-3, the volume 16-1, 16-
2, 16-3 are adjusted individually.

When the echo level adjusting operator 38 is operated, the volume 22 is adjusted to the corresponding level adjustment value, and the volumes 16-1, 16-2, 16-3 are adjusted in the opposite direction, and all the microphone signals are adjusted. Level fluctuation is prevented. That is, when one microphone is connected, the volume 2 is connected similarly to the first and second embodiments (FIGS. 1 and 5).
The level adjustment amount of one corresponding volume 16 is changed in the opposite direction by half the amount of change in the level adjustment value of 2 (for example, if the volume 22 fluctuates by +6 dB, the corresponding one volume 16 becomes − Fluctuates by 3 dB). When two microphones 10 are connected, the level adjustment amounts of the two corresponding volume units 16 are changed in the opposite directions by the same amount of change as when one microphone is connected (for example, the volume unit 22).
Is +6 dB, the two corresponding regulators 16 vary by -3 dB. ). The microphone 10 is 3
When this connection is made, 3
The level adjustment amount of each of the volumes 16 is changed in the opposite direction (for example, if the volume 22 changes by +6 dB, each of the three volumes 16 changes by -3 dB). In addition, actually, the volume 16-1, 16-
It is not necessary to detect the system to which the microphone is connected and perform the change control of the level adjustment values of 2, 16-3 only for that system, regardless of which system the microphone is connected to. Volume 16-1, 16-2, 1
6-3 may be uniformly varied by the same amount (because the volume of a system to which a microphone is not connected remains 0 regardless of whether the volume level adjustment value is varied or not). , Does not affect the overall playback volume.)

(Embodiment 4) In the above embodiments, the regulators 16 and 22 are arranged in tandem, but they may be arranged in parallel as shown in FIG. That is, the volume 22 is arranged in the signal path 18 for echo signal generation, and the volume 16 is arranged in the signal path 20 for direct sound.
The volume 22 is adjusted according to the operation of the echo level adjustment operator 38, and the volume 16 is adjusted according to the operation of the microphone level adjustment operator 36. Since the level adjustment of the direct sound signal by the volume 16 and the level adjustment of the echo signal by the volume 22 do not interfere with each other, at the time of the echo level adjustment, as shown in FIG. The 16 level adjustment amounts are varied.

(Embodiment 5) An embodiment of the present invention in which the level adjustment of a direct sound signal and an echo signal is performed by a mechanical volume control will be described. According to this, the operation value detection units and the control circuit of the operators 36, 38, and 40 are not required. FIG. 9 shows the signal system.
The microphone signal output from the microphone 10 is input from the microphone signal input terminal 12, and the level is adjusted by a volume (attenuator) 62 via the head amplifier 14. The level-adjusted microphone signal is supplied to the echo signal generation signal path 18.
And directly to the signal path 20 for sound. The microphone signal branched to the echo signal generation signal path 18 is further level-adjusted by a volume (attenuator) 64 and then input to the delay circuit 24 to generate an echo signal. The level of the microphone signal (direct sound signal) branched to the direct sound signal path 20 is further adjusted by a volume 66 (attenuator). The synthesis circuit 26 adds and combines the level-adjusted echo signal and the direct sound signal.

All the microphone signals output from the synthesizing circuit 26 are added and synthesized with the music signal (accompaniment sound signal) in the synthesizing circuit 28, the level is adjusted by a volume (attenuator) 68, and then amplified by an amplifier 32. The sound is reproduced from the speaker 34.

Each of the regulators 62, 64 and 68 is constituted by a mechanical regulator such as a rotary or linear variable resistor. The microphone level adjusting operation member 36 is used for adjusting the microphone level, and is directly connected to the movable portion of the volume 16 to variably operate the volume 62. By manipulating the operation element 36, the level of the microphone signal before branching to the signal path 18 for echo signal generation and the signal path 20 for direct sound is variably adjusted. As a result, the level of the direct sound signal and the level of the echo signal are adjusted. Is increased or decreased to an arbitrary value while maintaining a constant ratio. Incidentally, the volume 62 can be arranged between the synthesizing circuits 26 and 28.

The echo level adjusting operator 38 is used for adjusting the echo level.
The volume 64, 66 is variably operated by being directly connected to the movable portions 4, 66. FIG. 10 shows the relationship between the operation amount of the echo level adjustment operator 38 and the level adjustment values of the volumes 64 and 66. According to FIG. 10, the increase / decrease relationship of the level adjustment values of the volumes 64 and 66 is opposite to each other, and the sum of these level adjustment values is always 0 dB. Therefore, the level of the echo signal can be adjusted without changing the levels of all microphone signals.

The main level adjustment operator 40 is used to adjust the total output level including the music signal and the microphone signal, and is directly connected to the movable part of the volume 68 to control the volume.
Variable operation. By operating the operation element 40,
The level of all output signals (the sum signal of the music signal and all microphone signals) is increased or decreased to an arbitrary value.

The microphone level adjusting device according to the present invention
It can be used for applications other than the karaoke device.

[Brief description of the drawings]

FIG. 1 is a signal system diagram showing Embodiment 1 of the present invention.

FIG. 2 is a signal system diagram showing a conventional device.

FIG. 3 is a flowchart showing echo level adjustment control by the microcomputer of FIG. 1;

4 is a characteristic diagram showing a relationship between a level adjustment value of the volume 22 and a level adjustment value increase / decrease amount of the volume 16 according to the control flow of FIG.

FIG. 5 is a signal system diagram showing Embodiment 2 of the present invention.

FIG. 6 is a signal system diagram showing Embodiment 3 of the present invention.

FIG. 7 is a signal system diagram showing Embodiment 4 of the present invention.

8 is a characteristic diagram showing a relationship between a level adjustment value of the volume 22 and a level adjustment value increase / decrease amount of the volume 16 in the configuration of FIG.

FIG. 9 is a signal system diagram showing Embodiment 5 of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between the operation amount of the echo level adjustment operator 38 and the level adjustment values of the volumes 64 and 66 in the configuration of FIG.

[Explanation of symbols]

 Reference Signs List 10 Microphone 16 First electronically controlled volume 18 Echo signal generation signal path 20 Direct sound signal path 22 Second electronically controlled volume 24 Delay circuit (echo signal generation circuit) 26 Synthesis circuit 28 Second synthesis circuit 30 Electronically controlled volume (output level adjustment circuit) 32 Amplifier 34 Speaker 36 Microphone level adjustment operator 38 Echo level adjustment operator 40 Main level adjustment operator 42 Microphone level adjustment device 44 Karaoke device 46 Level adjustment circuit 48, 50 Operation value detection Part 54 Microcomputer (control circuit) 62, 64, 66 Mechanical volume 68 Mechanical volume (output level adjustment circuit)

Claims (6)

[Claims] A microphone signal input terminal for inputting a microphone signal; an echo signal generation circuit for generating an echo signal of the microphone signal input from the microphone signal input terminal; A synthesizing circuit for synthesizing a sound signal and the echo signal; a microphone level adjusting operator for adjusting a microphone level; an echo level adjusting operator for adjusting an echo level; and the microphone level adjusting operator When operated, the level adjustment value of the direct sound signal is increased or decreased in accordance with this operation, and the level adjustment value of the echo signal is also increased or decreased, and the echo level adjustment operation member is adjusted. At this time, the level adjustment value of the echo signal is increased or decreased in accordance with this operation, and the level of the direct sound signal is increased. Seichi microphone level adjusting device formed by and a level adjusting circuit for adjusting, respectively, as decrease or increase in the reverse level adjustment value of the direct sound signal and the echo signal. 2. The level adjustment circuit according to claim 1, wherein the ratio of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is changed to a value before the operation when the microphone level adjustment operation is operated. The level adjustment values of the direct sound signal and the echo signal are adjusted in a state where they are substantially kept, and when the echo level adjustment operator is operated, the level adjustment value of the direct sound signal and the level adjustment of the echo signal are adjusted. 2. The microphone level adjustment device according to claim 1, wherein the level adjustment values of the direct sound signal and the echo signal are adjusted while the sum of the values is substantially maintained at the value before the operation. 3. An electronically controlled volume for variably adjusting a level adjustment value of the direct sound signal and the echo signal at an arbitrary level ratio, the microphone level adjustment operator and the echo level adjustment. An operation value detection unit that detects an operation value of an operation element, and a control circuit that adjusts and controls the electronically controlled volume based on detection information of these operation value detection units, wherein the control circuit includes: When the microphone level adjustment operator is operated to adjust, the direct sound signal and the echo signal are kept in a state where the ratio between the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is almost maintained at the value before the operation. Each of the signal level adjustment values is adjusted, and when the echo level adjustment operation is operated, the sum of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is calculated. 2. The microphone level adjustment device according to claim 1, wherein the level adjustment values of the direct sound signal and the echo signal are adjusted while substantially maintaining the values before the operation. 4. The control circuit stores, when the echo level adjusting operator is operated for adjustment, operation values of the microphone level adjusting operator and the echo level adjusting operator immediately before the operation, respectively. The sum of the level adjustment value of the direct sound signal and the level adjustment value of the echo signal is obtained from the value, and the level adjustment value of the echo signal is changed to a value corresponding to the operation value after the adjustment operation of the echo level adjustment operator. 4. The microphone level adjustment device according to claim 3, wherein the level adjustment value of the direct sound signal is changed to a value such that the sum of the level adjustment value of the echo signal and the level adjustment value of the echo signal becomes substantially equal to the obtained value. 5. A first electronically controlled volume disposed on a signal line of a direct sound signal before the electronically controlled volume branches to the echo signal generation circuit, and after the electronically controlled volume is branched to the echo signal generation circuit. A second electronically controlled volume disposed on the input side of the echo signal generation circuit, wherein the control circuit operates the second electronically controlled volume when the microphone level adjustment operation element is operated. The first electronically controlled volume is adjusted in a corresponding direction by fixing the level adjustment value of the first electronically controlled volume, and when the echo level adjusting operation element is operated, the second electronically controlled volume is adjusted in the corresponding direction. 5. The microphone level adjusting device according to claim 3, wherein the first volume is adjusted in a reverse direction by an adjustment amount substantially half of that of the second electronic volume. 6. A microphone level adjusting device according to claim 1, further comprising: a second synthesizing circuit for synthesizing an output signal of said synthesizing circuit and a separately input music signal. A main level adjustment operator for adjusting the level of the output signal of the synthesis circuit; and an output for increasing or decreasing the level adjustment value of the output signal of the second synthesis circuit in accordance with the adjustment operation of the main level adjustment operator. A karaoke apparatus comprising: a level adjusting circuit; an amplifier for amplifying a composite signal output from the output level adjusting circuit; and a speaker for reproducing the amplified composite signal.