DESCRIPTION JPH11313389

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DESCRIPTION JPH11313389
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
audio apparatus suitable when the number of reconnections of speakers is relatively large.
[0002]
2. Description of the Related Art In order to check the performance of loudspeakers, a plurality of
loudspeakers may be connected instead of one amplifier (amplifier).
[0003]
By the way, when connecting a plurality of speakers instead of the amplifier as described above,
it is often the case that the amplifier is kept alive without turning off the power supply of the
amplifier.
However, if the speaker is switched during the operation of the amplifier, the connection
conductor of the speaker may irregularly contact the terminal of the amplifier, and noise may be
generated from the speaker. Also, as another problem, when disconnecting a speaker with a large
allowable power from an amplifier and connecting a speaker with a small allowable power, the
small allowable power with the volume of the amplifier set so that the output level is relatively
large. Connecting the speaker may cause damage to the speaker.
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[0004]
Therefore, a first object of the present invention is to provide an audio device capable of
suppressing noise when connecting or disconnecting a speaker. A second object of the present
invention is to provide an audio apparatus capable of suppressing speaker breakage or
unpleasant high level audio output at the time of speaker connection.
[0005]
According to a first aspect of the present invention, there is provided an audio signal supply
circuit, a terminal for connecting a speaker to the audio signal supply circuit, and a terminal for
connecting the speaker to the audio signal supply circuit. Speaker connection state detecting
means for detecting at least one of the operation of connecting the connection conductor of the
speaker and the operation of releasing the connection, and the operation of connecting and
disconnecting the connection from the speaker connection state detecting means And means for
interrupting the supply of the audio signal from the audio signal supply circuit to the terminal
when the detection signal indicating at least one of the operations is obtained. It is a thing. The
second invention for achieving the second object is an audio signal supply circuit, a terminal for
connecting a speaker to the audio signal supply circuit, and a connection conductor of the
speaker to the terminal. A speaker connection state detection unit for detecting at least one of an
operation to connect and an operation to cancel the connection, and at least one of an operation
to connect from the speaker connection state detection unit and an operation to cancel the
connection Control the level adjuster for adjusting the amplitude level of the audio signal
included in the audio signal supply circuit in response to the detection signal to lower the
amplitude level when the detection signal indicating The present invention relates to an audio
apparatus characterized by including control means.
[0006]
According to the first aspect of the present invention, the supply of the audio signal is stopped
when the speaker connecting wire is disconnected from the terminal or when the speaker
connecting wire is connected to the terminal. It is possible to prevent the generation of noise due
to intermittent contact. As a result, connection or disconnection of the speaker can be performed
without unpleasant noise while keeping the sound signal supply circuit alive. Further, according
to the second aspect of the present invention, it is possible to prevent the speaker from being
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driven in a state in which the level adjuster of the audio signal supply circuit is set to an
excessive level, thereby preventing breakage of the speaker and discomfort. It is possible to
prevent the generation of excessive noise automatically.
[0007]
Embodiments and Examples Next, embodiments and examples of the present invention will be
described with reference to the drawings.
[0008]
First Embodiment The audio apparatus of the first embodiment shown in FIGS. 1 to 3 comprises
a combination of an amplifier as an audio signal output device, that is, an amplifier 1 and a
speaker 2. As shown in FIG.
[0009]
The amplifier 1 includes an audio signal input terminal 3, an input amplification circuit 4, a
variable resistor (volume) 5 as a volume level adjuster, an output amplification circuit 6, and a
signal cutoff switch provided according to the present invention, and first and second Speaker
connection terminals 8 and 9, power supply terminal 10, power supply switch 11, power supply
circuit 12, volume controller 13, motor drive circuit 14, motor 15 and control relay 16 of switch
7 and connection state detection switch 17 for speaker 2 It consists of
[0010]
In the amplifier 1, an input terminal 3 constituting an audio signal supply circuit, an input
amplification circuit 4, a variable resistor 5, and an output amplification circuit 6 are sequentially
connected.
The output terminal of the output amplifier circuit 6 is connected to the first speaker connection
terminal 8 through the switch 7, and the ground terminal is connected to the second speaker
connection terminal 9.
The speaker 2 is connected to the first and second speaker connection terminals 8 and 9 by first
and second connection conductors 19 and 20 formed of conductive wires.
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[0011]
The slider 5 a of the variable resistor 5 as a level adjuster is connected to the motor 15.
Therefore, the slider 5 a is displaced by the rotational movement of the motor 15, and the signal
attenuation amount in the variable resistor 5 is changed. Control of the motor 15 is performed by
controlling the drive circuit 14 connected to the motor 15 by the controller 13.
[0012]
The input terminal of the power supply circuit 12 is connected to the power supply terminal 10
through the power supply switch 11, and the output terminal of the power supply circuit 12 is
connected to the input amplifier circuit 4, the output amplifier circuit 6, the controller 13, the
drive circuit 14, and the relay 16. It is done.
[0013]
First and second speaker connection state detection switches 17 and 18 are connected between
the ground side terminal of the relay 16 and the ground.
The first and second speaker connection state detection switches 17 and 18 perform connection
and disconnection operations of the first and second speaker connection conductors 19 and 20
to the first and second speaker connection terminals 8 and 9, respectively. The first and second
speaker connection terminals 8 and 9 are engaged to detect the presence or absence. The relay
16 controls the switch 7 to turn off the switch 7 by this excitation.
[0014]
FIGS. 2 and 3 schematically show the relationship between the first speaker connection terminal
8, the first speaker connection conductor 19 and the first speaker connection state detection
switch 17. FIG. The terminal 8 has plate-like first and second terminal conductors 21 and 22, a
flat plate-like insulating support 23, and a pressing operation portion by a finger at the upper
part, and is an operation piece formed in a flat plate shape as a whole 24 and a biasing spring 25
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shown in an explanatory manner. The support 23 is fixed to the container of the amplifier 1. The
support 23 may be part of the container of the amplifier 1.
[0015]
The first terminal conductor 21 is fixed to the support 23. The second terminal conductor 22 is
movable relative to the support 23 and fixed to the operation piece 24. The operation piece 24
has a hole 26 for inserting a connection conductor 19 made of a conductor, and can be moved
downward in FIG. 2 together with the second terminal conductor 22. The spring 25 is disposed
so as to always press the operation piece 24 upward as shown by the arrow. The operation piece
24 is held so as to move only in the vertical direction in FIG. 2 by a guide member not shown. In
FIG. 2, since the second terminal conductor 22 is biased upward together with the operation
piece 24, the speaker connecting conductor 19 is sandwiched between the first and second
terminal conductors 21 and 22, and the complete connection state of both is It is established.
[0016]
The connection state detection switch 17 is formed of a micro switch fixed to the support 23, and
the operation portion 17 a is disposed in the passage of the operation piece 24. When the
conductor 19 is completely connected to the terminal 8 as shown in FIG. 2, the switch 17 is not
operated by the operation piece 24 and is kept in the off state.
[0017]
When releasing the speaker connecting conductor 19, the operating piece 24 is pushed down as
shown in FIG. 3 against the bias of the spring 25. As a result, the second terminal conductor 22
also moves downward, and the holding of the connection conductor 19 by the first and second
terminal conductors 21 and 22 is released, and the connection conductor 19 can be pulled out
from the terminal 8. When the operation piece 24 is depressed, the operation portion 17a
formed of the elastically displaceable projection of the connection state detection switch 17 is
pressed by the operation piece 24 and the switch 17 is turned on.
[0018]
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When the depression of the operation piece 24 is released after pulling out the connection
conductor 19 from the terminal 18, the operation piece 24 is moved upward by the force of the
spring 25 and at the position where the first and second terminal conductors 21, 22 are engaged.
Stop. Of course, the upper limit stopper of the operation piece 24 can also be provided. When the
conductor 19 is not connected to the terminal 8, the detection switch 17 is off. When connecting
the connection conductor 19 to the terminal 8, the operation piece 24 is pushed down to form a
gap in which the connection conductor 19 can be inserted between the first and second terminal
conductors 21, 22. Is inserted, and then the depression of the operation piece 24 is released.
Thereby, the complete connection state of FIG. 2 can be obtained.
[0019]
The second terminal 9 and the second connection state detection switch 18 in FIG. 1 are
configured in the same manner as the first terminal 9 and the first connection state detection
switch 17.
[0020]
The power switch 11 of the amplifier 1 of FIG. 1 may be turned on, and the connection and
disconnection of the speaker 2 may be performed with the audio signal being input to the input
terminal 3.
If the switches 7, 17 and 18 are not provided, the connection conductor 19 makes incomplete
contact with the terminal conductors 21 and 22 during the operation of connecting or
disconnecting the speaker connecting conductor 19 and the connection conductor 19 does not
contact the terminal conductor 21. , 22 when an audio signal is supplied to the speaker 2, a
sound is emitted from the speaker 2. This sound is irregular and unpleasant. On the other hand,
when the switches 7, 17, 18 are provided, no unpleasant noise is generated. For example, when
the operation piece 24 is depressed to separate the connection conductor 19 in FIG. 2, the state
detection switch 17 is turned on, the relay 16 is energized, the switch 7 is turned off, and the
audio signal is supplied to the terminal 8 Is interrupted, and even if the terminal conductors 21
and 22 incompletely contact the connection conductor 19 when the connection conductor 19 is
pulled out, no audio signal is supplied to the speaker 2 and no noise (unpleasant noise) is
generated. Also when connecting the connecting conductors 19 and 20 to the terminals 8 and 9,
since the switch 7 is temporarily turned off, no noise is generated from the speaker 2.
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[0021]
As apparent from the above, according to the present embodiment, the generation of unpleasant
noise at the time of connection and disconnection of the speaker 2 can be prevented with a
simple configuration.
[0022]
Second Embodiment Next, an audio apparatus according to a second embodiment of the present
invention will be described with reference to FIG.
However, in FIG. 4, the same reference numerals as in FIGS. 2 and 3 denote the substantially
same parts as in FIG. The audio apparatus of the second embodiment is the same as that of FIG. 1
except that the operation mechanism of the connection state detection switches 17 and 18 of
FIG. 1 is modified. See also FIG.
[0023]
The terminal 8 shown in FIG. 4 and the terminal 9 shown in FIG. 1 are surrounded by a terminal
box 30. The terminal box 30 is composed of a side wall 31 and a lid 32 surrounding the four
terminals 8 and 9 in the upper, lower, left, and right directions, and the lid 32 is supported by the
side wall 31 openably and closably by a hinge 33. The side wall 31 is fixed to the support 23.
The lid 32 has a hole 34 for inserting the two connection conductors 19 and 20, and a locking
means (shown in the figure) for reliably holding the lid 32 closed with respect to the side wall 31.
Have).
[0024]
In the second embodiment, the second connection state detection switch 18 of the first
embodiment is omitted, and the first connection state detection switch 17 is provided. The
connection state detection switch 17 is fixed to the side wall 31 of the terminal box 30 and is
arranged to respond to the opening and closing of the lid 32. That is, when the lid portion 32 is
closed, the operating portion 17a of the switch 17 is pressed by the lid portion 32 and the switch
17 is kept off. When the lid portion 32 is opened as shown by a broken line, the switch 17 is
turned on. Thus, the switch 17 and the lid 32 are associated with each other. Therefore, in FIG. 4,
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the normally closed contact of the switch 17 is used for detection.
[0025]
In FIG. 4, when the cover 32 is opened to disconnect the connection conductor 19 from the
terminal 8 or to connect to the terminal 8, the detection switch 17 of the normally closed contact
configuration is switched from off to on, and the relay 16 of FIG. The switch 7 is turned off and
the supply of the audio signal to the terminal 8 is cut off. For this reason, even if the connection
conductor 19 irregularly (intermittently) contacts the terminal 8 in a state in which the lid
portion 32 is opened, no audio output is generated from the speaker 2. Therefore, the second
embodiment can prevent the generation of unpleasant noise as in the first embodiment.
[0026]
Third Embodiment The third embodiment will be described with reference to FIG. However, in
FIG. 5, substantially the same parts as those in FIG. 1 will be assigned the same reference
numerals and explanations thereof will be omitted.
[0027]
The audio apparatus 1 of FIG. 5 is the same as that of FIG. 1 except that the controller 13a
operates the variable resistor 5 in response to the on / off of the speaker connection state
detection switches 17 and 18. The controller 13a of FIG. 5 controls the drive circuit 14 to
increase the amount of attenuation in the variable resistor 5 in response to the detection
switches 17 and 18 being turned on. Thereby, the supply of the audio signal of the excessive
level to the speaker 2 is prevented. That is, when the speaker connecting conductors 19 and 20
are attached to or detached from the terminals 8 and 9, the switches 17 and 18 are turned on,
and the controller 13a responds to this and attenuates the slider 5a of the variable resistor 5
Move in the larger direction. Therefore, for example, when another speaker with a small
allowable power is connected to the terminals 8 and 9, the speaker is not driven according to the
adjustment level of the variable resistor 5 before this connection. If a high level audio signal is
supplied to a speaker with a large allowable power and then a high level audio signal is directly
supplied to a speaker with a small allowable power, the rear speaker may be damaged. If you
lower the level by, no damage to the speaker will occur. In addition, even if the variable resistor 5
is erroneously set to a high level while connecting a speaker, control to lower the level occurs at
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the time of connecting the speaker later, so that damage to the speaker and abnormal highpitched sound may occur. Occurrence is prevented. After the connection of the speaker, the
variable resistor 5 is adjusted to set the volume to an appropriate level. The audio device of FIG.
5 also has the switch 7 as in FIG. 1, so that the generation of noise when connecting and
disconnecting the connection conductors 19 and 20 can be prevented.
[0028]
[Modifications] The present invention is not limited to the above-described embodiment, and for
example, the following modifications are possible. (1) The switch 18 can be omitted from FIG. 5
and the switch 17 can be turned on / off by the same mechanism as that of FIG. (2) Although the
switches 17 and 18 are turned on when attaching and detaching the connection conductors 19
and 20 to and from the terminals 8 and 9 in each embodiment, they may be turned off. In this
case, the switch 7 is associated with the relay 16 so that it is turned off in response to the turning
off of the switches 17 and 18. (3) In FIG. 4, the detection switch 17 can be disposed outside the
terminal box 30 and can be made responsive to the opening and closing of the lid 32. (4) The
switch 7 can be provided on the input side of the amplifier circuit 6.
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