JP2009206612

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DESCRIPTION JP2009206612
[Problem] A comfortable bass feeling is obtained by using a bass speaker. A low frequency
component generation unit generates low frequency component low frequency component
signals SAA (j = C to SR) corresponding to low frequency speakers from separated channel
signals SCA to SCA which are other channel signals. Further, the correlation evaluation unit 330
performs correlation evaluation between the separation channel signal SCA, which is a low-pass
sound effect channel signal, and the separation channel signal SCA. Then, the bass signal
generation unit 340 performs gain adjustment on the low frequency component signal SAA to
reduce the gain amount if the correlation is strong and increase the gain amount if the
correlation is weak, and delay this adjustment signal and the delay unit 320. And the low pass
delay signal SDA. A sound reflecting the addition result is output from the subwoofer speaker
131 which is a bass speaker. [Selected figure] Figure 4
Audio apparatus, audio reproduction method, audio reproduction program and recording
medium therefor
[0001]
The present invention relates to an audio apparatus, an audio reproduction method, an audio
reproduction program, and a recording medium on which the audio reproduction program is
recorded.
[0002]
2. Description of the Related Art Conventionally, audio devices that reproduce audio content and
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output reproduced audio from a speaker are widely used.
Such an acoustic device sometimes lacks a feeling of bass.
[0003]
For this reason, in order to compensate for the lack of bass feeling, an acoustic device capable of
obtaining a clear bass effect by generating a bass signal from a voice channel signal has been
proposed (see Patent Document 1: "Conventional Example: Call it "). In the prior art, a bass
component is generated from an audio channel signal, and the bass component is added to the
audio channel signal itself to enhance the bass signal.
[0004]
JP 2007-67628 A
[0005]
However, in the above-described prior art, since the generated bass component is added to the
audio channel signal itself, the speaker for the audio channel not dedicated to bass (for example,
left channel, light channel etc. in 2-channel stereo system) When the aperture is small, the
generated bass signal may not be reproduced and output effectively.
For this reason, the prior art often can not obtain a sufficient bass effect.
[0006]
By the way, with the spread of DVD (Digital Versatile Disk) etc., audio devices compatible with
multi-channel surround systems such as 5.1 channel and 7.1 channel are in widespread use. In
the 5.1 channel or 7.1 channel multi-channel surround system, a low-frequency sound effect
channel (LFE channel) is prepared as an audio channel, and a subwoofer speaker which is a bass
speaker for the LFE channel is used.
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[0007]
Since the LFE channel signal is an auxiliary audio channel signal to the last, the bass derived from
the LFE channel signal is often not output as audio from a subwoofer speaker that is a dedicated
bass speaker. In such a case, the user feels that the bass is lacking.
[0008]
For this reason, there is a demand for a new technology capable of reproducing and outputting
bass sound capable of producing an appropriate bass effect from a bass speaker such as a
subwoofer speaker who specializes in bass reproduction output. Responding to such a request is
one of the problems to be solved by the present invention.
[0009]
The present invention has been made in view of the above-described circumstances, and an
object thereof is to provide an audio apparatus and an audio reproduction method capable of
obtaining a comfortable bass feeling by using a bass speaker.
[0010]
The invention according to claim 1 is an audio apparatus for outputting audio from a plurality of
speakers including a bass speaker and at least one other speaker to a sound field space as a
reproduction result of audio content having a predetermined channel configuration. Channel
signal generating means for generating a plurality of channel signals including a low-pass sound
effect channel signal from the audio content; and correlating with each of at least one other
channel signal other than the low-pass sound effect channel signal; Low-pass component
generating means for generating a low-pass component signal in a low frequency band
corresponding to the bass speaker; evaluation of correlation between the low-pass sound effect
channel signal and each of the at least one other channel signal Evaluation means for performing
each of the low-pass component signals at a ratio determined based on the evaluation result by
the evaluation means An acoustic device, characterized in that it comprises a; superimposed to a
bass signal generating means for generating a bass signal output toward the woofer.
[0011]
The invention according to claim 10 is an audio apparatus for outputting audio from a plurality
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of speakers including a bass speaker and at least one other speaker to a sound field space as a
reproduction result of audio content having a predetermined channel configuration. An audio
reproduction method used, generating a plurality of channel signals including a low-pass sound
effect channel signal from the sound content; and at least one other channel signal other than the
low-pass sound effect channel signal. A low-pass component generating step of generating a lowpass component signal having a correlation with each of the following; an evaluation step of
evaluating the correlation between the low-pass sound effect channel signal and each of the at
least one other channel signal; Superimposing each of the low-pass component signals at a ratio
determined based on the evaluation result in the evaluation step The bass signal generation step
of generating a bass signal output toward the woofer; an audio reproducing method
characterized by comprising a.
[0012]
The invention according to claim 11 is an audio reproduction program characterized by causing
the operation means to execute the audio reproduction method according to claim 10.
[0013]
The invention according to claim 12 is a recording medium characterized in that the audio
reproduction program according to claim 11 is recorded so as to be readable by an operation
means.
[0014]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1
to 9.
In the following description and the drawings, the same or equivalent elements will be denoted
by the same reference symbols, without redundant description.
[0015]
[Configuration] FIG. 1 is a block diagram showing a schematic configuration of an acoustic device
100 according to an embodiment.
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In the following description, it is assumed that the receiving apparatus 100 adopts the 5.1
channel surround system, which is one of multi-channel surround systems.
[0016]
As shown in FIG. 1, the acoustic device 100 includes a control unit 110 and a drive unit 120.
[0017]
The acoustic device 100 further includes a sound output unit 130C, a sound output unit 130L, a
sound output unit 130R, a sound output unit 130SL, a sound output unit 130SR, and a sound
output unit 130SW.
[0018]
Here, the sound output unit 130C has a center speaker 131C.
Further, the sound output unit 130L has a left speaker 131L, and the sound output unit 130R
has a light speaker 131R.
Further, the sound output unit 130SL has a surround left speaker 131SL, and the sound output
unit 130SR has a surround light speaker 131SR.
Further, the sound output unit 130SW has a subwoofer speaker 131SW.
[0019]
Furthermore, the acoustic device 100 includes a display unit 140 and an operation input unit
150.
[0020]
The elements 120 and 130 C to 130 SW, 140 and 150 other than the control unit 110 are
connected to the control unit 110.
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[0021]
The control unit 110 centrally controls the entire sound device 100.
The details of the control unit 110 will be described later.
[0022]
When the recording medium RM such as a DVD or the like in which audio content is recorded is
inserted into the drive unit 120, the drive unit 120 reports that effect to the control unit 110.
When the drive unit 120 receives the reproduction command DVC of the audio content from the
control unit 110 in the state where the recording medium RM is inserted, the drive unit 120
reads out the audio for which the reproduction is specified from the recording medium RM.
The readout result of the audio content is sent to the control unit 110 as content data CTD which
is an audio signal.
[0023]
Note that audio content is recorded on the recording medium RM in the 5.1 channel surround
system.
In the 5.1 channel surround system, as a sound channel, a center channel (hereinafter also
referred to as C channel ), a left channel (hereinafter also referred to as L channel ), and a
right channel (hereinafter referred to as R channel ) ), Surround left channel (hereinafter also
referred to as SL channel ), surround light channel (hereinafter also referred to as SR
channel ), low-pass sound effect channel (hereinafter also referred to as LFE channel ) .
[0024]
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Each of the sound output units 130C to 130SW includes an amplifier for amplifying the audio
output signals AOSC to AOSLFE received from the control unit 110, in addition to the speakers
131C to 131SW described above. The sound output units 130C to 130SW reproduce and output
music and the like according to the audio output signals AOSC to AOSLFE sent from the control
unit 110.
[0025]
The display unit 140 described above is based on, for example, (i) a display device such as a
liquid crystal panel, an organic EL (Electro Luminescence) panel, or a PDP (Plasma Display
Panel), and (ii) display control data sent from the control unit 110. A display controller such as a
graphic renderer which controls the entire display unit 140, and (iii) a display image memory for
storing display image data. The display unit 140 displays operation guidance information and the
like in accordance with display data IMD from the control unit 110.
[0026]
The operation input unit 150 described above is configured of a key portion provided on the
main body portion of the acoustic device 100 and / or a remote input device or the like including
the key portion. Here, a touch panel provided in the display device of the display unit 140 can be
used as the key part provided in the main body. It is also possible to adopt a configuration in
which voice input is performed using voice recognition technology instead of or in combination
with the configuration having the key part.
[0027]
When the user operates the operation input unit 150, the setting of the operation content of the
acoustic device 100 is performed. For example, an input by the user such as a reproduction
instruction of audio content is performed using the operation input unit 150. Such input contents
are sent from the operation input unit 150 to the control unit 110 as operation input data IPD.
[0028]
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Next, the control unit 110 will be described. As described above, the control unit 110 centrally
controls the entire sound device 100. The control unit 110 includes a control processing unit
111 and a channel signal processing unit 112, as shown in FIG. The control unit 110 also
includes an analog conversion unit 113 and a volume adjustment unit 114.
[0029]
The control processing unit 111 described above controls the drive unit 120, the display unit
140, and the volume adjustment unit 114 based on the command input to the operation input
unit 150. The details of the control processing unit 111 will be described later.
[0030]
The above-mentioned channel signal processing unit 112 processes the content data CTD sent
from the drive unit 120, and generates channel processing signals PCDC to PCDLFE
corresponding to the respective speakers 131C to 131SW. As shown in FIG. 3, the channel signal
processing unit 112 having such a function includes a channel separation unit 210 as a channel
signal generation unit, a bass enhancement unit 220, and a delay unit 230 as another channel
signal delay unit. ing.
[0031]
The above channel separation unit 210 receives the content data CTD from the drive unit 120.
Then, the channel separation unit 210 develops the content data CTD and generates a digital
sound data signal which is an audio signal. Subsequently, the channel separation unit 210
analyzes the generated digital sound data signal, and corresponds the digital sound data signal to
the C to LFE channel in the 5.1 channel surround system according to the channel designation
information included in the digital sound data signal. The signal is separated into six separate
channel signals SCAC, SCAL, SCASL, SCAR, SCASR, SCALFE. Among the signals separated in this
way, the separated channel signals SCAC to SCASR are sent to the bass enhancement unit 220
and the delay unit 230. Also, the separated channel signal SCALFE is sent to the bass
enhancement unit 220.
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[0032]
The bass emphasizing unit 220 described above receives the separated channel signals SCAC to
SCALFE from the channel separating unit 210, and generates a channel processing signal
PCDLFE that is a bass signal to be output to the subwoofer speaker 131SW. The bass
emphasizing unit 220 having such a function includes, as shown in FIG. 4, a low-pass component
generating unit 310 as a low-pass component generating unit, and a delay unit 320 as a low-pass
sound effect channel signal delay unit. There is. Further, the bass emphasizing unit 220 includes
a correlation evaluation unit 330 as an evaluation unit and a bass signal generation unit 340 as a
bass signal generation unit.
[0033]
The low frequency component generation unit 310 described above receives the separated
channel signals SCAC to SCALFE from the channel separation unit 210, and generates low
frequency component signals SAAC to SAALFE. The low-pass component generation unit 310
having such a function is, as shown in FIG. 5, a low-pass enhancement unit 311 as a low-pass
enhancement unit, a low pass filter (LPF) unit 312 as a filter unit, and a compensation unit. And
an all pass filter (APF) unit 313.
[0034]
The above-described low-frequency region enhancement unit 311 includes the individual lowfrequency region enhancement portions 311C to 311SR. Each of the individual low-frequency
band enhancers 311j (j = C to SR) receives, from the channel separator 210, for example, a
separated channel signal SCAj having a frequency distribution of sound pressure levels shown in
FIG. 6A. Then, the individual low band enhancement unit 311 j extracts a signal of a
predetermined frequency band from the separated channel signal SCAj, and generates a low band
signal of the 1 / N frequency (N-fold period) based on the extracted signal. Subsequently, the
individual low band enhancement unit 311j compares the sound pressure level of the separated
channel signal SCAj with the sound pressure level of the low band signal generated, and adjusts
the sound pressure level of the low band signal so that both signals are connected smoothly. Do.
Thereafter, the individual low-pass enhancer 311j adds the low-pass signal subjected to the level
adjustment and the separated channel signal SCAj. The signal thus added is output to the LPF
unit 312 as, for example, a low-pass boost signal SSAj having a frequency distribution of sound
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pressure levels shown in FIG. 6B.
[0035]
Here, a value larger than 1 is adopted as the value of N. The N and the predetermined frequency
band are predetermined based on experiments, simulations, experiences, etc. from the viewpoint
of generating a low frequency component signal of a low frequency band corresponding to the
subwoofer speaker 131SW. In the present embodiment, N is an integer of 2 or more.
[0036]
The low-frequency enhancement signal SSAj generated by the low-frequency enhancement unit
311 has a delay of time DL1 compared to the separation channel signal SCAj.
[0037]
Referring back to FIG. 5, the above-described LPF unit 312 includes LPFs 312C to 312SR.
Each of the LPFs 312 j (j = C to SR) is configured as a digital filter such as an infinite impulse
response filter (IIR), and receives the low-frequency enhancement signal SSAj from the individual
low-frequency enhancement unit 311 j of the low-frequency enhancement unit 311. . Then, the
LPF 312 j selectively passes frequency components lower than a predetermined frequency. Thus,
the signal that has passed through the LPF 312 j is sent to the APF unit 313 as a signal SLA j.
[0038]
Note that, in the filtering process in the LPF 312j, a delay of time DL2 occurs in the signal SLAj
that has passed through the LPF 312j. Further, the signal SLAj that has passed through the LPF
312j has a change in phase having frequency characteristics as shown in FIG. 7A, for example, in
the vicinity of the cutoff frequency FC.
[0039]
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Referring back to FIG. 5, the APF unit 313 described above includes APFs 313C to 313SR. Each
of the APF 313 j (j = C to SR) is configured as a digital filter such as an infinite impulse response
filter (IIR). The APF unit 313 has, for example, a frequency phase characteristic that cancels out
the phase change in the above-described LPF 312 j as shown in FIG. 7B.
[0040]
The APF 313 j receives the signal SLA j from the LPF 312 j of the LPF unit 312, passes the signal
SLA j in all frequency ranges, and, for example, changes the phase of the signal SLA j changed in
the LPF 312 j as shown in FIG. To compensate. The signal that has passed through the APF 313 j
in this way is sent to the bass signal generator 340 as a low-pass component signal SAAj.
[0041]
Referring back to FIG. 4, the delay unit 320 receives the separated channel signal SCALFE from
the channel separation unit 210. Then, the delay unit 320 delays the separation channel signal
SCALFE by a time (DL1 + DL2) substantially matching the delay time generated in the process of
the low frequency component generation unit 310 described above. As a result, synchronization
between the separated channel signal SCALFE and the low frequency component signal SAAj (j =
C to SR) output from the low frequency component generation unit 310 is achieved. The delay
result is sent to the bass signal generation unit 340 as the low pass delay signal SDALFE.
[0042]
The above-mentioned correlation evaluation part 330 is provided with individual correlation
evaluation parts 331C-331SR, as shown in FIG. Each of the individual correlation evaluation units
331 j (j = C to SR) receives the separation channel signal SCAj from the channel separation unit
210 and the separation channel signal SCALFE. The individual correlation evaluation unit 331 j
then evaluates the correlation between the separation channel signal SCALFE and the separation
channel signal SCAj which is another channel signal. Here, this correlation is evaluated using a
known correlation coefficient Rj.
[0043]
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The correlation coefficient Rj takes a value in the range of -1 to 1. Then, the correlation
coefficient Rj takes a positive value if the correlation between the separation channel signal
SCALFE and the separation channel signal SCAj which is another channel signal (hereinafter, also
simply referred to as correlation ) has a positive phase, If it is out of phase, it takes a negative
value. Further, the correlation coefficient Rj takes an absolute value close to 1 if the
correlation is strong, and takes a value close to 0 if the correlation is weak.
[0044]
Subsequently, the individual correlation evaluation unit 331 j generates an individual gain
control signal MXSj based on the evaluation result using the correlation coefficient Rj. When
generating the individual gain control signal MXSj, the individual correlation evaluation unit 331
j performs adjustment to reduce the gain of the low frequency component signal SAAj with
respect to the bass signal generation unit 340 described later if the correlation is strong, and low
if the correlation is weak. Adjustment is performed to increase the gain of the component signal
SAAj. As a result, it is possible to suppress excessive reproduction of the bass when the
correlation is strong in the positive phase, or cancellation and reproduction of the bass when the
correlation is strong in the negative phase. Also, if the correlation is weak, bass can be
emphasized, and a comfortable bass feeling can be obtained. A gain control signal MXS including
the individual gain control signals MXSC to MXSSR generated in this manner is sent to the bass
signal generation unit 340.
[0045]
As shown in FIG. 9, the above-described bass signal generation unit 340 includes variable
multiplication units 341C to 341SR and an addition unit 342.
[0046]
Each of variable multipliers 341 j (j = C to SR) receives low-pass component signal SAAj from lowpass component generator 310 and also receives individual gain control signal MXSj from
correlation evaluator 330.
Then, the variable multiplying unit 341j multiplies the low-pass component signal SAAj by the
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coefficient designated by the individual gain control signal MXSj. The variable multiplication unit
341 j directs the multiplication result to the addition unit 342.
[0047]
The addition unit 342 receives the multiplication results from the variable multiplication units
341C to 341SR, and receives the low pass delay signal SDALFE from the delay unit 320. Then,
the adding unit 342 adds the multiplication result and the low-pass delay signal SDALFE. The
addition unit 342 outputs the addition result to the analog conversion unit 113 as a channel
processing signal (bass signal) PCDLFE.
[0048]
Returning to FIG. 3, the delay unit 230 receives the separated channel signals SCAC to SCASR
from the channel separation unit 210. Then, each of the separation channel signals SCAC to
SCASR is delayed by a time (DL1 + DL2) substantially corresponding to the delay time generated
in the process of the low frequency component generation unit 310 of the bass enhancement
unit 220 described above. Thereby, the separation channel signal SCAj (j = C to SR) and the
channel processing signal PCDLFE which is a bass signal output from the bass enhancing unit
220 can be synchronized. The delay result is output to the analog conversion unit 113 as
channel processing signals PCDC to PCDSR.
[0049]
Returning to FIG. 2, the above-described analog conversion unit 113 converts the channel
processing signals PCDC to PCDLFE, which are digital signals sent from the channel signal
processing unit 112, into analog signals. The analog conversion unit 113 includes six DA (Digital
to Analogue) converters configured in the same manner, corresponding to the six digital signals.
The analog signals PBSC to PBSLFE that are conversion results by the analog conversion unit 113
are sent to the volume adjustment unit 114.
[0050]
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The volume control unit 114 described above receives the analog signals PBSC to PBSLFE from
the analog conversion unit 113. Then, the volume adjusting unit 114 adjusts the volume
according to the volume adjustment command VLC from the control processing unit 111 for
each of the analog signals PBSC to PBSLFE. The adjustment result is output to the sound output
units 130C to 130SW as the audio output signals AOSC to AOSLFE.
[0051]
Next, the control processing unit 111 will be described. The control processing unit 111 exerts
the function of the acoustic device 100 while controlling the other components described above.
The control processing unit 111 outputs the display data IMD, and causes the display unit 140 to
display a guidance screen for supporting specification of audio content to be reproduced by the
user. Then, when a reproduction command specifying audio content is input from the operation
input unit 150, the control processing unit 111 issues a reproduction command DVC to the drive
unit 120, and controls data reading of the reproduction content.
[0052]
Further, the control processing unit 111 controls the volume adjustment unit 114 to adjust the
output volume from the speakers 131C to 131SW of the sound output units 130C to 130SW.
When controlling the output volume, the control processing unit 111 generates a volume
adjustment command VLC in accordance with the volume specification input to the operation
input unit 150, and sends the volume adjustment command VLC to the volume adjustment unit
114.
[0053]
[Operation] Next, the operation of the acoustic device 100 configured as described above will be
described focusing mainly on the bass signal generation process.
[0054]
When the user inserts a recording medium RM such as a DVD into the drive unit 120 and inputs
a reproduction command specifying audio content to the operation input unit 150, the effect is
sent to the control processing unit 111 as operation input data IPD (See Figure 2).
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When receiving the reproduction command, the control processing unit 111 issues a
reproduction command DVC to the drive unit 120 and controls data reading of the reproduction
content. Under such control, the content data CTD read from the recording medium RM is sent to
the channel separation unit 210 (see FIG. 3). The channel separation unit 210 that has received
the content data CTD expands and analyzes the content data CTD, and six SCACs, SCALs, SCASLs,
SCARs, SCASRs, SCALFEs corresponding to the C to LFE channels in the 5.1 channel surround
system. To separate. Among the signals separated in this way, the separated channel signals
SCAC to SCASR are sent to the bass enhancement unit 220 and the delay unit 230. Also, the
separated channel signal SCALFE is sent to the bass enhancement unit 220.
[0055]
In the bass enhancement unit 220, the low-pass component generation unit 310 receives the
separation channel signals SCAC to SCASR, and the delay unit 320 receives the separation
channel signal SCALFE. Further, the correlation evaluation unit 330 receives the separated
channel signals SCAC to SCALFE (see FIG. 4).
[0056]
The low-pass component generation unit 310 that receives the separated channel signal SCAj (j =
C to SR) first generates the low-pass enhancement signal SSAj in each of the individual low-pass
boost units 311 j in the low-pass boost unit 311 (see FIG. 5). When generating the low-frequency
enhancement signal SSAj, the individual low-frequency enhancement unit 311j extracts a signal
of a predetermined frequency band from the separated channel signal SCAj, and based on the
extracted signal, the low-frequency signal of 1 / N frequency is extracted. Generate Then, the
individual low band enhancement unit 311 j compares the sound pressure level of the separated
channel signal SCAj with the sound pressure level of the low band signal, and adjusts the sound
pressure level of the low band signal so that both signals are smoothly connected. The low-pass
signal subjected to level adjustment and the separated channel signal SCAj are added. The lowpass boost signal SSAj generated in this manner is output to the LPF unit 312.
[0057]
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In the LPF unit 312 that has received the low-frequency enhancement signal SSAj, each of the
LPFs 312 j selectively passes frequency components lower than a predetermined frequency.
Thus, the signal that has passed through the LPF 312 j is output to the APF unit 313 as a signal
SLA j.
[0058]
In the APF unit 313, each of the APFs 313j compensates for the change in phase generated in the
filtering process in the LPF 312j. Thus, the signal that has passed through the APF 313 j is
output to the bass signal generation unit 340 as a low-pass component signal SAAj.
[0059]
Also, the delay unit 320 that has received the separation channel signal SCALFE delays the
separation channel signal SCALFE by a time (DL1 + DL2) that substantially matches the delay
time generated in the process of the low-pass component generation unit 310. The delay result is
output to the bass signal generation unit 340 as the low band delay signal SDALFE.
[0060]
Further, in correlation evaluation section 330 having received separation channel signals SCAC
to SCALFE, each of individual correlation evaluation section 331 j in correlation evaluation
section 330 uses separation coefficient Rj to obtain separation channel signal SCALFE and other
channel signals. The correlation between the separated channel signal SCAj is evaluated (see FIG.
8). Then, the individual correlation evaluation unit 331 j generates an individual gain control
signal MXSj based on the evaluation result of the correlation. The individual gain control signals
MXSC to MXSSR thus generated are sent to the bass signal generator 340 as the gain control
signal MXS.
[0061]
In the bass signal generation unit 340 that has received the low-pass component signals SAAC to
SAASR and the low-pass delay signal SDALFE, first, the variable multiplication unit 341 j (j = C to
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SR) reduces the coefficient designated by the individual gain control signal MXSj The frequency
component signal SAAj is multiplied (see FIG. 9). The multiplication result is sent to the adding
unit 342. The addition unit 342 adds the multiplication result and the low band delay signal
SDALFE, and outputs the result to the analog conversion unit 113 as a channel processing signal
PCDLFE which is a bass signal.
[0062]
Further, a channel processing signal PCDj obtained by delaying the separated channel signal SCAj
by time (DL1 + DL2) is input to the analog conversion unit 113 by the delay unit 230.
[0063]
Thereafter, the channel processing signals PCDC to PCDLFE are converted into analog signals in
the analog conversion unit 113, and the volume adjustment is further performed in the volume
adjustment unit 114 to generate the audio output signals AOSC to AOSLFE.
Then, the audio output signals AOSC to AOSLFE are supplied to the sound output units 130C to
130SW (see FIG. 2).
[0064]
As a result, the sound reflecting the other channel signal recorded on the CD is output from the
speakers 131C to 131SR, and the sound reflecting the LFE channel signal and the bass signal
generated from the other channel signal from the subwoofer speaker 131SW It is output.
[0065]
As described above, in the present embodiment, the low frequency component generation unit
310 generates the low frequency component low frequency component signal SAAj (j = C)
corresponding to the low frequency speaker from the separated channel signals SCAC to SCASR
that are other channel signals. ˜ SR) is generated.
Further, the correlation evaluation unit 330 performs correlation evaluation between the
separation channel signal SCALFE which is a low-pass sound effect channel signal and the
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separation channel signal SCAj which is another channel signal. Then, the bass signal generation
unit 340 performs gain adjustment on the low frequency component signal SAAj if the
correlation is strong and reduces the gain amount, and if the correlation is weak, the gain amount
is increased. And the low pass delay signal SDALFE. A sound reflecting the addition result is
output from the subwoofer speaker 131SW which is a bass speaker. For this reason, it is possible
to suppress that the bass is reproduced excessively when the correlation is strong in the positive
phase, or the bass is canceled and reproduced when the correlation is strong in the reverse
phase. Also, if the correlation is weak, bass can be emphasized. Further, in order to output the
sound derived from the bass signal from the subwoofer speaker 131SW which is a bass speaker,
it is not necessary to set the output speaker corresponding to the other channel signal to follow
the low frequency band.
[0066]
Further, in the present embodiment, the APF unit 313 is provided to compensate for the change
in phase of the signal SLAj (j = C to SR) generated when passing through the LPF unit 312.
Therefore, the bass signal generation unit 340 can perform the addition of the signals in phase
with each other.
[0067]
Further, in the present embodiment, the delay units 230 and 320 are provided, and the lowfrequency component signal SAAj (j = C to SR) input to the bass signal generation unit 340 is
synchronized with the low-frequency delay signal SDALFE. . Therefore, the bass signal generation
unit 340 can perform the addition of the synchronized signals.
[0068]
Therefore, according to the present embodiment, it is possible to obtain a comfortable bass
feeling by using the bass speaker.
[0069]
[Modification of Embodiment] The present invention is not limited to the above embodiment, and
various modifications are possible.
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[0070]
For example, in the above embodiment, the correlation evaluation unit performs correlation
evaluation between the separated channel signal SCAj (j = C to SR) which is another channel
signal and the separated channel signal SCALFE.
On the other hand, for example, as shown in FIG. 10, the correlation evaluation unit 330 B
generates the low frequency component signal SAAj generated by the low frequency component
generation unit 310 and the low frequency delay signal SDALFE output from the delay unit 320.
And the correlation between
In addition, correlation evaluation may be performed between the signal SLAj that has passed
through the LPF unit 312 of the low-pass component generation unit 310 and the low-pass delay
signal SDALFE output from the delay unit 320.
[0071]
Although the cutoff frequency in the LPF unit 312 is a fixed value in the above embodiment, the
control processing unit 111 may control the cutoff frequency in accordance with the user's
designation. In this case, the control processing unit 111 controls the phase ensuring function in
the APF unit 113 together.
[0072]
In the above embodiment, the signal output from the channel separation unit is a digital audio
signal, and the bass enhancement unit performs bass enhancement processing on the digital
audio signal. On the other hand, the signal output from the channel separation unit may be
converted into an analog audio signal, and the bass enhancement unit may perform bass
enhancement processing on the analog audio signal.
[0073]
In the above embodiment, it is assumed that the audio content has a channel configuration
including an LFE channel, but when the audio content has a channel configuration not including
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an LFE channel, the channel separation unit serves as an LFE channel signal. , And may generate
a serro level signal.
[0074]
In the above embodiment, six speakers are provided. However, as long as it is provided with a
speaker for bass and a speaker for outputting an audio reflecting other channel signals, the
speaker configuration is not limited. It is also good.
[0075]
In the above embodiment, the drive unit 120 is a drive unit of a recording medium such as a
DVD, but may be a fixed disk.
Furthermore, broadcast wave reception circuits such as radio broadcasts and terrestrial digital
television broadcasts, audio input circuits of external devices, and the like can also be used.
[0076]
The control unit in the above embodiment is configured as a computer system provided with a
central processing unit (CPU: Central Processor Unit) or DSP (Digital Signal Processor), and the
functions of the control processing unit and the like are realized by executing a program. You can
do so.
These programs may be acquired in the form of being recorded on a portable recording medium
such as a CD-ROM or a DVD, or may be acquired in the form of delivery via a network such as the
Internet. Good.
[0077]
FIG. 1 is a block diagram schematically showing a configuration of an acoustic device according
to an embodiment of the present invention. It is a block diagram which shows the structure of
the control unit of FIG. It is a block diagram which shows the structure of the channel signal
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processing part of FIG. It is a block diagram which shows the structure of the bass emphasis part
of FIG. It is a block diagram which shows the structure of the low-pass component production ¦
generation part of FIG. It is a figure for demonstrating the production ¦ generation process of a
low-pass enhancement signal. It is a figure for demonstrating the phase change in a low pass
filter, and the phase compensation in an all pass filter. It is a block diagram which shows the
structure of the correlation evaluation part of FIG. It is a block diagram which shows the
structure of the bass signal production ¦ generation part of FIG. It is a figure for demonstrating a
modification.
Explanation of sign
[0078]
DESCRIPTION OF SYMBOLS 100 ... Acoustic device 131C-131SR ... Speaker (other speaker)
131SW ... Speaker (bass speaker) 210 ... Channel separation part (channel signal generation
means) 230 ... Delay part (other channel signal delay means) 310 ... Low-pass component
generation part (Low-pass component generation means) 311 ... low-pass enhancement part
(low-pass enhancement means) 312 ... low-pass filter part (filter means) 313 ... all-pass filter part
(compensation means) 320 ... delay part (low-pass sound channel signal delay means 330 ...
correlation evaluation unit (evaluation means) 340 ... bass signal generation unit (bass signal
generation means)
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