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JP2008301205

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2008301205
The present invention makes it possible for a listener to clearly and unambiguously listen to a
sound generated from a central sound source, even when listening to a reproduced sound in
stereo at different positions from the speakers. It is an object of the present invention to provide
an audio output device and an audio output method which make it possible and suitable for
practical use. SOLUTION: Audio control means (54 to 56) for adding a first and a second audio
signal for performing stereo audio reproduction to extract a signal of a specific frequency band
and outputting it as a third audio signal And audio output means (45, 46, 51, 52) for subtracting
the power spectrum of the portion allocated to the third audio signal from the first and second
audio signals and outputting the result. [Selected figure] Figure 3
Voice output device and voice output method
[0001]
The present invention relates to an audio output apparatus and an audio output method for
outputting audio signals of a plurality of channels for reproducing audio by stereo.
[0002]
As well known, for example, in two-channel stereo audio reproduction, a speaker for reproducing
left-channel audio and a speaker for reproducing right-channel audio are normally disposed at a
predetermined interval, and the listener uses both speakers. By listening to the sound reproduced
from each speaker at the center, a three-dimensional sound effect is obtained.
[0003]
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1
In this case, for example, the voice generated from the center sound source, such as the voice of
the announcer, is often reproduced at the same level and in the same phase from the speakers
corresponding to the left and right channels. The so-called center localization sound reproduction
is provided in which the sound source is felt to be present at the central part of both speakers.
[0004]
As described above, when the left and right speakers are caused to perform sound reproduction
at the same level and the same phase, a listener present at the center of both speakers can listen
to a good sound at the center localization.
However, for a listener who exists at a position shifted from the central part of both speakers,
that is, at a position at which the distance from each speaker is different, the clarity of the voice
is deteriorated.
[0005]
In patent document 1, a center channel speaker is provided in addition to the left and right
channel speakers, and audio signals of the left and right channels are synthesized, and frequency
components containing a large amount of human voice from the synthesized signal are narrow
band An arrangement is disclosed in which the clarity is improved by removing the center
channel speaker and smoothing the center channel speaker.
Japanese Patent Application Laid-Open No. 10-322800
[0006]
Therefore, the present invention has been made in consideration of the above-mentioned
circumstances, and when listening to stereo playback audio, audio generated from the central
sound source can be generated even if the users are listening at different positions from each
speaker. An object of the present invention is to provide an audio output device and an audio
output method which enable a listener to listen clearly and without discomfort and which is
suitable for practical use.
08-05-2019
2
[0007]
An audio output apparatus according to the present invention comprises an input unit to which a
first audio signal and a second audio signal for performing stereo audio reproduction are input, a
first audio signal input to the input unit, and Voice control means for adding the two voice
signals to extract a signal of a specific frequency band and outputting it as a third voice signal,
and the power allocated to the third voice signal output from the voice control means An audio
output means is provided for subtracting the spectrum from the first audio signal and the second
audio signal input to the input means and outputting the result.
[0008]
Further, according to the audio output method of the present invention, there is provided a first
step of inputting a first audio signal and a second audio signal for performing stereo audio
reproduction, and a first step of inputting the first audio signal and the second audio signal.
Voice signal and second voice signal are added to extract a signal of a specific frequency band
and output as a third voice signal, and third voice signal output in the second step And a third
step of subtracting and outputting the power spectrum of the portion allocated to the first audio
signal and the second audio signal input in the first step.
[0009]
According to the invention described above, the first audio signal and the second audio signal are
added to extract a signal of a specific frequency band and output it as a third audio signal, and it
is allocated to the third audio signal. Since the power spectrum of the audio signal is subtracted
from the first audio signal and the second audio signal and output, respectively, even when
listening to the reproduced audio, even if it is heard at a position where the distance from each
speaker is different, The sound from the central sound source allocated to the third sound signal
can be made clear to the listener without a sense of discomfort, which is suitable for practical
use.
[0010]
Hereinafter, embodiments of the present invention will be described in detail with reference to
the drawings.
FIG. 1 shows a state in which the television broadcast receiver 11 described in this embodiment
is viewed from the front side.
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The television broadcast receiver 11 mainly includes a thin cabinet 12 and a support 13 for
supporting the cabinet 12.
[0011]
Among these, the flat display panel 14 is disposed in the center of the front of the cabinet 12.
And, on the lower side of the flat panel 14, the cabinet 12 has speakers 15 and 16 for
reproducing sound of left (L) and right (R) channels for sound reproduction by 2-channel stereo,
both speakers A center speaker 17, an operation unit 18, and a reception unit 20 for receiving
operation information sent from the wireless remote controller 19 are disposed in the central
part of 15, 16, and the like.
[0012]
On the other hand, the support base 13 is rotatably connected to the central portion of the
bottom surface of the cabinet 12 so that the cabinet 12 can be erected and supported in a state
where the support base 13 is mounted on the horizontal surface of a predetermined base 21. Is
configured.
[0013]
FIG. 2 schematically shows a signal processing system of the television broadcast receiver 11.
It is assumed that various circuit blocks constituting the signal processing system are mainly
disposed at a position near the back surface inside the cabinet 12, that is, around the back
surface of the flat display panel 14.
[0014]
The digital television broadcast signal received by the antenna 22 for digital television broadcast
reception is supplied to the tuner unit 24 through the input terminal 23.
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The tuner unit 24 tunes and demodulates a signal of a desired channel from the input digital
television broadcast signal.
Then, the signal output from the tuner unit 24 is supplied to the decoder unit 25 and, for
example, subjected to MPEG (moving picture experts group) 2 decoding processing, and then
supplied to the selector 26.
[0015]
Furthermore, an analog television broadcast signal received by the antenna 27 for analog
television broadcast reception is supplied to the tuner unit 29 through the input terminal 28. The
tuner unit 29 tunes and demodulates a signal of a desired channel from the input analog
television broadcast signal. The signal output from the tuner unit 29 is digitized by an A / D
(analog / digital) conversion unit 30 and then output to the selector 26.
[0016]
The analog video and audio signals supplied to the input terminal 31 for analog signals are
supplied to the A / D converter 32 and digitized, and then output to the selector 26. Further,
digital video and audio signals supplied to the input terminal 33 for digital signals are supplied to
the selector 26 as they are.
[0017]
The selector 26 selects one of four types of input digital video and audio signals and supplies the
selected signal to the signal processing unit 34. The signal processing unit 34 performs
predetermined signal processing on the input digital video signal and outputs the processed
signal to the video display unit 35 including the flat display panel 14. The video display unit 35
drives the flat display panel 14 based on the input video signal to display video.
[0018]
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In addition, the signal processing unit 34 performs predetermined signal processing on the input
digital audio signal to generate digital audio signals of the left and right channels for 2-channel
stereo, converts each into an analog signal, and performs audio control. It is output to the part
36. The audio control unit 36 outputs the analog audio signals of the left and right channels
input to the speakers 15 and 16 to perform audio reproduction of two-channel stereo, although
the details will be described later. A predetermined process is applied to the analog audio signals
of the left and right channels which are selectively output to the speakers 15 and 16 and the
center speaker 17 so as to perform audio reproduction by user operation. It is supposed to be
[0019]
Here, in the television broadcast receiver 11, various operations including the various reception
operations described above are integrally controlled by the control unit 37. The control unit 37
incorporates a CPU (central processing unit) or the like, and based on the operation information
from the operation unit 18 or the operation information transmitted from the remote controller
19 and received via the reception unit 20. Each unit is controlled so that the contents of the
operation are reflected.
[0020]
In this case, the control unit 37 mainly includes a ROM (read only memory) 38 storing a control
program to be executed by the CPU, a random access memory (RAM) 39 for providing a work
area to the CPU, and the like. A non-volatile memory 40 in which setting information, control
information and the like are stored is used.
[0021]
FIG. 3 shows an example of the voice control unit 36.
That is, the analog audio signal of the left (L) channel output from the signal processing unit 34
is supplied to the left channel speaker 15 from the output terminal 44 as it is by the switches 42
and 43 after passing through the input terminal 41. And the second path supplied from the
output terminal 44 to the speaker 15 for the left channel through the equalizer 45 and the
amplifier 46.
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[0022]
The analog audio signal of the right (R) channel output from the signal processing unit 34 is
supplied via the input terminal 47 to the right channel speaker 16 from the output terminal 50
as it is by the switches 48 and 49. And the second path supplied from the output terminal 50 to
the speaker 16 for the right channel through the equalizer 51 and the amplifier 52.
[0023]
The switches 42, 43, 48, 49 selectively select the first path and the second path based on the
switching control signal output from the control unit 37 and supplied via the control terminal 53.
It is switched to form.
The control unit 37 generates a switching control signal based on the operation of the operation
unit 18 or the remote controller 19 by the user.
[0024]
Here, the analog audio signals of the left and right channels led to the second path by the
switches 42 and 48 are added by the adding unit 54, and then output through the band pass
filter 55 and the amplifying unit 56. At 57, the signal is supplied to the center speaker 17.
[0025]
The band pass filter 55 extracts a frequency band (for example, 0.3 kHz to 8 kHz) that
contributes to the intelligibility of human voice from the analog voice signal added by the adding
unit 54.
Then, the analog audio signal output from the band pass filter 55 is amplified (intensified) by the
amplifier 56 and then supplied from the output terminal 57 to the center speaker 17 to be
reproduced as audio.
[0026]
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The equalizer unit 45 and the amplification unit 46, and the equalizer unit 51 and the
amplification unit 52 are added by the addition unit 54 and processed by the band pass filter 55
and the amplification unit 56, so that the analog audio signal of the center is obtained. It
functions to subtract the allocated power spectrum from the analog audio signal of the left and
right channels, respectively.
[0027]
Therefore, when the user performs an operation to request the first path, the analog audio signal
of the left channel supplied to the input terminal 41 is reproduced as it is by the speaker 15
through the output terminal 44. The analog audio signal of the right channel supplied to the
input terminal 47 is reproduced as it is by the speaker 16 through the output terminal 50, and
the audio reproduction of the normal two-channel stereo is realized.
[0028]
On the other hand, when the user performs an operation for requesting the second path, analog
voice signals of the left and right channels are added to extract and amplify a frequency band
that contributes to the intelligibility of human voice. The audio is reproduced by the center
speaker 17 and the analog audio signals of the left and right channels from which the power
spectrum allocated to the audio signal given to the center speaker 17 is subtracted are
reproduced by the speakers 15 and 16. become.
For this reason, even if it listens in the position from which the distance from each speaker 15
and 16 for stereos differs, it becomes possible to listen to the sound generated from a single
sound source clearly without sense of incongruity.
[0029]
Here, FIGS. 4 and 5 schematically show how the sound wave propagates when sound signals of
the same phase are reproduced at the same frequency from the speakers 15 and 16 for the left
and right channels of 2-channel stereo. It is shown in.
[0030]
Now, as shown on the solid line A shown in FIG. 4, when listening at the central portion of both
08-05-2019
8
speakers 15 and 16, that is, at the same distance from the speakers 15 and 16, voice Regardless
of the frequency of the signal, the phases of the sound waves generated from the speakers 15
and 16 are always aligned.
Therefore, it is possible to realize center-localized sound reproduction with respect to the sound
generated from the central sound source without disturbing the frequency characteristic at that
position.
[0031]
On the other hand, when the distance from each of the speakers 15 and 16 is different by one
wavelength (about 17 cm) at a certain frequency (for example 2 kHz) of the audio signal, as
shown on the solid line B in FIG. At this frequency, since the phases of the sound waves
generated from the speakers 15 and 16 are aligned, the sound pressure becomes high.
[0032]
On the other hand, when the frequency of the audio signal is 1 kHz, at which the difference in
distance from each of the speakers 15 and 16 is 1⁄2 wavelength, sound waves of opposite phase
arrive at positions on the same solid line B, as shown in FIG. To reduce the sound pressure due to
the interference of the two waves.
In the sound wave shown in FIG. 5, the density of the sound wave is represented by the dotted
line and the solid line, and the interval between the dotted line and the solid line indicates a half
wavelength.
[0033]
That is, at the position on the same solid line B, the frequency of the audio signal is 2 wavelength
difference, 3 wavelength difference, ..., n wavelength difference between the speakers 15 and 16,
4 kHz, 6 kHz, ... The sound pressure appears high when ..., and the frequency of the audio signal
is 1.5 wavelength difference, 2.5 wavelength difference, ..., n + 0.5 wavelength difference in the
distance difference from each speaker 15, 16 The sound pressure will drop at 3 kHz, 5 kHz, ....
[0034]
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9
FIG. 6 shows sound pressure characteristics when the frequency of the audio signal is changed at
the position on the line of the solid line B. In FIG.
As described above, it can be seen that the sound pressure is high and low depending on the
frequency of the audio signal.
Thus, when listening to the sound reproduced from the speakers 15 and 16 for the left and right
channels of 2-channel stereo at different positions from the speakers 15 and 16, the frequency
characteristics according to the frequency of the sound signal As a result, the clarity of the voice
for a single sound source is degraded.
[0035]
Therefore, in this embodiment, when the user wants to improve the intelligibility of voice to a
single sound source, the operation of requesting the above-mentioned second path is executed.
As a result, the analog audio signals of the left and right channels are added, and the frequency
band that contributes to the intelligibility of human voice is extracted and amplified while the
sound is reproduced by the center speaker 17 while being given to the center speaker 17 The
analog sound signals of the left and right channels with the power spectrums allocated to the
sound signals being reduced are reproduced by the speakers 15 and 16.
[0036]
In this case, the power spectrum of the sound reproduced by the center speaker 17 is sufficiently
higher than the power spectrum of the sound reproduced by the speakers 15 and 16 for the left
and right channels. That is, the power spectrum of the sound reproduced by the speakers 15 and
16 is lower than the power spectrum of the sound reproduced by the center speaker 17 to a level
at which the user does not notice the sound.
[0037]
For this reason, equivalently, as shown in FIG. 7, the sound waves generated from the speakers
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15 and 16 can be audibly ignored, and only the sound waves generated from one center speaker
17 are provided for listening. become. As a result, no interference is caused by sound waves from
a plurality of sound sources, and even when listening at positions where the distances from the
two-channel stereo speakers 15 and 16 are different, the sound generated from the central
sound source can be made clear without discomfort. It becomes possible to listen.
[0038]
FIG. 8 shows a flowchart summarizing the audio reproduction processing operation in the
television broadcast receiver 11 described above. That is, when the process is started (step S1),
the control unit 37 determines in step S2 whether or not voice reproduction is started. If it is
determined that the process is started (YES), the center is selected in step S3. It is determined
whether the use of the speaker 17 is requested, that is, whether the formation of the abovedescribed second path is requested.
[0039]
When it is determined that the use of the center speaker 17 is not requested (NO), the control
unit 37 switches the switches 42, 43, 48, 49 to form a first path in step S4. And the process ends
(step S6). Thus, normal two-channel stereo audio reproduction is realized.
[0040]
When it is determined in step S3 that the use of the center speaker 17 is requested (YES), the
control unit 37 performs the second path along the switch 42, 43, 48, 49 in step S5. It switches
so as to form, and ends the process (step S6). As a result, sound reproduction with improved
intelligibility of sound from a single sound source is realized.
[0041]
Here, in the above-described embodiment, although the sound reproduction of the television
broadcast receiver 11 has been described, the present invention is not limited to this, and it is of
course possible to be applied to sound reproduction in a radio receiver or the like.
08-05-2019
11
[0042]
Although the above-described embodiment has described the audio reproduction by two-channel
stereo, it is obvious that the left and right audio signals are effective for the same monaural
source.
Further, the present invention is of course applicable not only to this but also to, for example, a
multi-channel stereo audio reproduction system of four or more channels.
[0043]
Furthermore, in the state where the second path is formed, the power spectrum of the audio
signal given to the center speaker 17 and the power of the audio signal given to the speakers 15
and 16 for the left and right channels by using a graphic equalizer etc. The spectrum may be
adjusted by the user by the operation of the operation unit 19 or the remote controller 19.
[0044]
The present invention is not limited to the above-described embodiment as it is, and at the
implementation stage, the constituent elements can be variously modified and embodied without
departing from the scope of the invention.
In addition, various inventions can be formed by appropriately combining a plurality of
components disclosed in the above-described embodiment. For example, some components may
be deleted from all the components shown in the embodiment. Furthermore, components
according to different embodiments may be combined as appropriate.
[0045]
The embodiment of this invention is shown, and it is a front view shown in order to demonstrate
the external appearance of a television broadcasting receiver. The block block diagram shown in
order to demonstrate the signal processing system of the television broadcast receiver in the
embodiment. The block block diagram shown in order to demonstrate the audio | voice control
part of the television broadcast receiver in the embodiment. The figure which showed typically
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12
an example of the propagation of the sound wave generate | occur | produced from the speaker
for the left and right channels of 2 channel stereo. The figure which showed typically the other
example of propagation of the sound wave generate | occur | produced from the speaker for left
and right channels of 2 channel stereo. The figure which shows the sound pressure characteristic
at the time of listening to the audio | voice reproduced | regenerated from the speaker for left
and right channels of 2 channel stereo in the position from which the distance from each speaker
differs. The figure shown in order to demonstrate equivalently the audio | voice reproduction |
regeneration by the center speaker of the television broadcast receiver in the embodiment. The
flowchart shown in order to demonstrate the sound reproduction processing operation of the
television broadcast receiver in the embodiment.
Explanation of sign
[0046]
11 television broadcasting receiver 12 cabinet 13 support base 14 flat panel display 15 speaker
16 speaker 17 center speaker 18 operation unit 19 remote controller 20 reception Unit, 21:
base, 22: antenna, 23: input terminal, 24: tuner unit, 25: decoder unit, 26: selector, 27: antenna,
28: input terminal, 29: tuner unit, 30: A / D conversion Sections 31 ... input terminals 32 ... A / D
conversion sections 33 ... input terminals 34 ... signal processing sections 35 ... video display
sections 36 ... audio control sections 37 ... control sections 38 ... ROMs 39 ... RAM , 40: nonvolatile memory, 41: input terminal, 42: switch, 43: switch, 44: output terminal, 45: equalizer
unit, 46: amplification unit, 47: input terminal, 48: switch, 9 ... switch, 50 ... output terminal, 51 ...
equalizer, 52 ... amplifier unit, 53 ... control terminal, 54 ... adding unit, 56 ... band-pass filter, 57
... output terminal.
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