JPH114499

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DESCRIPTION JPH114499
[0001]
FIELD OF THE INVENTION This invention relates to audio systems, and more particularly to test
tone output switching devices.
[0002]
2. Description of the Related Art Heretofore, when playing Dolby® in an audio system, it has
been necessary to uniformly adjust the balance of sound pressure levels of a plurality of speakers
with respect to the viewing position. This adjustment is performed, for example, by an analog IC
or DSP (digital signal processor) IC (hereinafter referred to as an output IC) that outputs a test
tone consisting of noise noise "Ther" and a microcomputer that controls the same. Of the center
(C), surround light (SR) and surround left (SL) speakers to switch the output destination and emit
sound from each speaker so that the volume is the same as the left front (LF) and right front (RF)
speakers. It was done by adjusting the sound pressure.
[0003]
However, in the above adjustment method, switching shock noise occurs when the
microcomputer communicates with the output IC and the output IC switches the output
destination of the test tone.
[0004]
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Therefore, as a measure against this shock noise, there is an adjustment method of controlling
the muting circuit so that the shock noise is not output when the output IC switches the test tone
output destination.
[0005]
FIG. 3 is a block diagram showing an example of a conventional test tone output switching
device.
In FIG. 3, 1 is a microcomputer, 2 is an output IC, 3 is an audio input terminal, 4 to 8 is an
electronic volume, 9 is a left front (LF) speaker, 10 is a light front (RF) speaker, 11 is a center (C
Speakers 12 are surround light (SR) speakers 13, 13 are surround left (SL) speakers, 14 is a
muting switch, and 15 is a microcomputer connection (including a key input unit, a display unit,
a remote control unit, etc.).
[0006]
FIG. 4 is a flowchart of the adjustment operation in the block diagram of FIG.
Here, as an example, the case where the sound pressure of the center (C) speaker is adjusted
based on the sound pressure of the left front (LF) speaker will be described. First, in step S11, a
test tone of reference sound pressure is output from the LF speaker 9 from the output IC 2
through the electronic volume 4, and the user remembers the sound pressure of the LF speaker 9
on hearing.
[0007]
In step S12, the muting switch 14 is turned on under the control of the microcomputer 1 to mute
all the input sides of the electronic volumes 4 to 8. Therefore, no sound is output from the LF
speaker 9. Next, in step S13, the microcomputer 1 sets the built-in advance muting timer to a
predetermined time (for example, 48 milliseconds), and then in step S14, after counting up the
advance muting timer (after 48 milliseconds), the microcomputer 1 Send the C speaker switching
command to the output IC2. As a result, the output IC 2 switches the output destination of the
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test tone from the LF speaker 9 to the C speaker 11, but the test volume is not supplied to the
electronic volume 6 since the muting switch is still off at the switching time. There is no sound
from 11.
[0008]
Next, in step S15, the microcomputer 1 sets the built-in post-out muting timer to a
predetermined time (for example, 150 milliseconds), and then in step S16, the microcomputer 1
counts up the post-out muting timer (150 ms) After the lapse, the muting switch 14 is turned off
and the test tone from the output IC 2 is supplied to the electronic volume 6. Next, in step S17, a
test tone is output from the C speaker 11 via the electronic volume 6. Thereafter, the user adjusts
the electronic volume 6 dedicated to the C speaker 11 by operating the volume adjustment (up /
down) key of the key input section, and the sound pressure of the C speaker 11 is listened to
first. It can be made to be the same in sound pressure and aural sense.
[0009]
The SR and SL speakers 12 and 13 can be adjusted to the sound pressure of the LF speaker 9 as
a reference by the same operation as described above.
[0010]
However, in this way, when setting test tones audibly (compare to each speaker), muting is
applied at the time of switching, so it is difficult to adjust the sound pressure of the speakers.
there were.
[0011]
An object of the present invention is to provide a test tone output switching device in an audio
system which solves the conventional problems.
[0012]
A test tone output switching device according to the present invention comprises a plurality of
adjustment means for adjusting a test tone sound pressure level of each of a plurality of speakers
in an audio system using a plurality of speakers. The first adjusting means corresponding to the
reference speaker among the plurality of adjusting means is set to a predetermined value for
giving a reference sound pressure level to the corresponding speaker, and at the same time, the
adjusting means other than the first adjusting means is minimized. Then, the second adjustment
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means corresponding to the speaker to be adjusted can be varied, and at the same time, the
adjustment means other than the second adjustment means can be set to the minimum value. Do.
[0013]
[Operation] When sound pressure levels of a plurality of speakers are audibly adjusted using a
test tone, among the plurality of speakers, only the adjustment means corresponding to the
speaker whose sound pressure level is to be adjusted is made variable. All adjustment means
corresponding to the speakers are fixed at the minimum value.
Therefore, shock noise at the time of output IC switching as in the prior art can be adjusted
without using a muting circuit, and it becomes easy to adjust.
[0014]
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an
embodiment of a test tone output switching device in an audio system according to the present
invention.
In FIG. 1, 1 is a microcomputer, 2 is an output IC, 3 is an audio input terminal, 4 to 8 is an
electronic volume, 9 is a left front (LF) speaker, 10 is a light front (RF) speaker, 11 is a center (C
), 12 surround sound (SR) speakers, 13 surround left (SL) speakers, 15 are microcomputer
connections (including a key input unit, a display unit, a remote control unit, etc.).
[0015]
In FIG. 1, the muting switch 14 (FIG. 3) conventionally used when adjusting the sound pressure
levels of a plurality of speakers audibly using test tones at the time of adjustment of Dolby
Surround is eliminated. There is.
Therefore, the output IC 2 can always output the test tone to all the electronic volumes 4 to 8
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simultaneously and at the same level.
Next, the microcomputer 1 appropriately switches the volume values of the electronic volumes 4
to 8 corresponding to the speakers 9 to 13 to switch the output destination of the test tone.
Specifically, among the plurality of speakers, only the electronic volume corresponding to the
speaker whose sound pressure level is to be adjusted is made variable, and all the electronic
volumes corresponding to the other speakers are fixed to the minimum value.
[0016]
FIG. 2 is a flow chart for explaining the above operation. At the time of adjustment, the output IC
2 always outputs the test tone to all the electronic volumes 4 to 8 simultaneously and at the
same level. Therefore, first, in S1, the test tone from the output IC 2 is supplied to the LF speaker
9 via the electronic volume 4 having the volume value before the start of adjustment and emitted.
At this time, the microcomputer 1 controls the electronic volumes 5 to 8 to set them to the
minimum value (for example, -78 dB), minimizes the sound pressure from the other speakers 10
to 13, and the user operates the other speakers 10 to 13 I can not listen from
[0017]
Next, in S2, the microcomputer 1 adjusts the electronic volume 4 by the user operating the
volume adjustment (up / down) key of the key input unit, for example, the sound pressure level
of the LF speaker 9 at the user's listening position Depending on the hearing you want the sound
pressure level you want. The user remembers this desired sound pressure level as a reference
sound pressure level on hearing. The standard sound pressure level is usually selected from LF or
RF speakers. Next, at step S3, the microcomputer 1 counts up the built-in adjustment timer
(about several seconds after the end of adjustment), and at step S4, the microphone computer 1
sets the electronic volume 4 for the LF speaker 9 to the minimum value (eg -78 dB) Do. The
adjustment timer starts counting when the volume adjustment (up / down) key of the key input
unit is operated, and is considered to have been adjusted when counting for a predetermined
time (for example, several seconds).
[0018]
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Next, at S5, the microcomputer 1 returns the volume value of the electronic volume 6 dedicated
to the C speaker 11 from the minimum value to the volume value before the start of adjustment.
Next, at S6, the test tone from the output IC 2 is supplied to the C speaker 11 via the electronic
volume 6 and emitted. At this time, the microcomputer 1 controls the electronic volumes 4, 5, 7
and 8 to set them to the minimum value (for example, -78 dB), and minimizes the sound pressure
from the other speakers 9, 10, 12 and 13. Prevent users from listening to other speakers. Next, in
S7, the microcomputer 1 changes the electronic volume 6 for the C speaker 11 based on the
volume up or down operation signal of the volume adjustment (up / down) key of the key input
unit by the user, and the sound of the C speaker 11 The pressure level is set to a volume value
that aurally matches the sound pressure level of the LF speaker 9 that has been heard earlier.
[0019]
The SR and SL speakers 12 and 13 can be adjusted to the sound pressure of the LF speaker 9 as
a reference by the same operation as described above.
[0020]
As described above, at the time of test tone switching, switching can be performed without
muting as in the prior art, and it becomes easy to adjust the sound pressure level of the aural
speaker.
[0021]
Also, microcomputer test tone control can be implemented without muting and thus without
complex timing control of muting.
[0022]
Also, conventionally, it has been necessary to control the DSP IC to output one channel at a time,
but in the present invention, the electronic control is performed without controlling the DSP IC
(by making all channels emit the sound). It is possible to adjust the volume of each channel
during Dolby Surround playback only by controlling the volume.
[0023]
In addition, since the adjustment process is simple, the program size of the microcomputer can
be small.
[0024]
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Furthermore, it is also effective for noise reduction of speakers that do not output sound in Dolby
Surround playback mode in which the speaker output is limited.
[0025]
According to the present invention, it is possible to obtain a test tone output switching device
which is easy to adjust without shock noise.
[0026]
Brief description of the drawings
[0027]
1 is a block diagram showing an embodiment of a test tone output switching device according to
the present invention.
[0028]
2 is a flowchart illustrating the operation of the block diagram of FIG.
[0029]
3 is a block diagram showing an example of a conventional test tone output switching device.
[0030]
4 is a flowchart illustrating the operation of the block diagram of FIG.
[0031]
Explanation of sign
[0032]
Reference Signs List 1 microcomputer 2 output IC 3 audio input terminal 4 electronic volume 5
electronic volume 6 electronic volume 7 electronic volume 8 electronic volume 9 left front (LF)
speaker 10 light front (RF) speaker 11 center (C) speaker 12 surround light (SR) Speaker 13
Surround left (SL) speaker 14 muting switch 15 microcomputer connection
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