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JP2008263562

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DESCRIPTION JP2008263562
An acoustic characteristic correction system capable of effectively realizing a desired acoustic
characteristic with simple processing. A CPU detects a peak and a dip of a difference value
frequency characteristic from a difference between a collected sound signal level and a desired
acoustic characteristic (S101 to S103). The CPU 11 determines the correction target peak / dip
based on the number of PEQs, detects these levels, and determines the set frequency and the
correction level of each (S104 to S106). The CPU 11 reads out different Q value parameters and
sets them in all PEQs of the equalizing processing unit 12 to perform simulation (S107). The CPU
11 calculates the difference value between the temporary correction signal level and the desired
acoustic characteristic, and compares the difference determination amount for each Q value
pattern (S108, S109). The CPU 11 detects a Q-value pattern with the smallest difference
determination amount, generates a parameter list, and transmits the parameter list to the
equalizing processing unit 12 (S110 to S112). [Selected figure] Figure 5
Acoustic characteristic correction system
[0001]
The present invention relates to a frequency characteristic correction system which measures an
acoustic transfer characteristic from a speaker to a listener position and corrects it to a desired
characteristic.
[0002]
Currently, there are various environments where ordinary people can enjoy music casually.
08-05-2019
1
One example is a karaoke box. In the karaoke box, a microphone used by a singer in a closed
space which is not so large, and a speaker for emitting a sound obtained by mixing audio
collected by the microphone and music sound of karaoke performance are installed. In such an
environment, there may be inherent acoustical properties depending on the environment and
may have acoustical properties that are not favored by the user. In addition, in such an
environment, a closed loop of sound transmission may be formed, and the signal level in a
particular frequency band may be extremely high to cause howling. To solve these problems, an
equalizer is installed in the karaoke apparatus or the like, and the acoustic characteristic is
corrected by the equalizer. For example, Patent Document 1 is to sequentially set a parametric
equalizer (PEQ) of an equalizer so as to attenuate a signal level in a frequency band to be
howling. There is also a method of correcting acoustic characteristics using a graphic equalizer
(GEQ) shown in Non-Patent Document 1. Patent Document 1: JP-A-8-84394 Yamaha Corporation,
[online], 2006, [March 27, 2007] Search, Internet <URL:
http://proaudio.yamaha.co.jp/products/processor/q2031b / index.html>
[0003]
However, in the above-mentioned acoustic characteristic correction system, the acoustic
characteristic satisfying the user can be realized finely and easily, such as by merely lowering the
signal level, or by uniquely setting the frequency range and limit value of the correction. It was
not easy. In addition, since multiple stages of PEQs and analog equalizers are set while
sequentially re-measuring, it is necessary to perform very complicated operations until desired
acoustic characteristics can be obtained.
[0004]
Therefore, an object of the present invention is to provide an acoustic characteristic correction
system capable of effectively realizing a desired acoustic characteristic with simple processing.
[0005]
The present invention comprises equalizing means comprising a plurality of stages of parametric
equalizers, and adjusting the set frequency, gain and Q value of the plurality of stages of
parametric equalizers to adjust the above-mentioned in a predetermined space in which a
microphone and a speaker are installed. The present invention relates to an acoustic
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2
characteristic correction system that corrects the acoustic characteristic of a system in which a
sound emitted from a speaker is propagated to a microphone position to a desired acoustic
characteristic.
The acoustic characteristic correction system according to the present invention detects the
frequency characteristic of the collected test signal obtained by collecting the test sound emitted
from the speaker by the microphone, detects the difference from the desired acoustic
characteristic, and detects the difference. A differential value frequency characteristic acquisition
means for acquiring a value frequency characteristic is provided. Further, the acoustic
characteristic correction system of the present invention detects the positive maximum and the
negative maximum of the difference value frequency characteristic, and the respective
frequencies and levels of the positive maximum and the negative maximum are set frequencies of
individual parametric equalizers. And a gain, and correction value candidate setting means for
sequentially allocating each Q value of a Q value group consisting of a different combination to a
positive maximum and a negative maximum. Furthermore, the acoustic characteristic correction
system according to the present invention acquires the temporarily corrected difference value
frequency characteristic for each combination of Q values set by the correction value candidate
setting means, and generates a desired sound from the plurality of provisionally corrected
difference value frequency characteristics. The Q value, the set frequency, and the gain that
constitute the temporarily corrected difference value frequency characteristics that minimize the
difference after detecting the temporarily corrected difference value frequency characteristics
that minimize the difference with the characteristics are detected. It is characterized in that it
comprises correction value setting means for setting in the equalizer.
[0006]
In this configuration, the difference value frequency characteristic acquisition means acquires the
difference value frequency characteristic that is the difference between the frequency
characteristic of the collected sound test signal and the desired acoustic characteristic. There is a
difference between the frequency characteristic of the sound pickup test signal according to the
current surrounding acoustic environment and the preset desired acoustic characteristic, and a
positive maximum on the frequency axis (hereinafter referred to as "peak") And a negative
maximum (hereinafter referred to as "dip") occur. The correction value candidate setting means
detects the peak and dip frequencies to set the set frequency, and sets the gain for each set
frequency from the peak and dip levels. The correction value candidate setting means stores in
advance a Q value group in which Q values for each parametric equalizer (hereinafter referred to
as "PEQ") are set in a plurality of patterns of different combinations, and sets them as PEQ for
each pattern. The correction value setting means obtains the difference value frequency
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characteristic after temporary correction for each pattern of the Q value group by acquiring the
difference value frequency characteristic again for each pattern of the Q value group. At this
time, the temporarily corrected difference value frequency characteristic may be calculated by
simulation or may be calculated by automatic remeasurement. Then, the correction value setting
means detects the temporarily corrected difference value frequency characteristic in which the
difference with respect to the desired acoustic characteristic is minimum, acquires the set
frequency, the gain, and each Q value of the Q value group constituting this, and equalizing
means To the PEQ of By executing such a configuration and processing, appropriate correction is
easily set without causing the user to perform complicated operations, and correction acoustic
characteristics corresponding to desired acoustic characteristics are realized.
[0007]
Further, the correction value setting means of the acoustic characteristic correction system of the
present invention is characterized in that the difference value frequency characteristic after
provisional correction is acquired from the correction result by all the stages of the parametric
equalizers of a plurality of stages.
[0008]
In this configuration, the provisionally corrected difference value frequency characteristics are
acquired in a state in which Q values are set to PEQs of all stages constituting the equalizing
means.
Thereby, the correction value can be determined on the basis of the effect of the correction in the
entire equalizing means.
[0009]
Further, the correction value setting means of the acoustic characteristic correction system of the
present invention is characterized in that the difference value frequency characteristic after
provisional correction is acquired from a set of correction results by each stage of a plurality of
stages of parametric equalizers.
[0010]
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In this configuration, Q values are sequentially set for each of the PEQs constituting the
equalizing means, and a correction result is obtained for each PEQ.
Thereby, the correction value can be determined on the basis of the superposition of the effect of
the correction by each PEQ.
[0011]
Further, the correction value candidate setting means of the acoustic characteristic correction
system of the present invention is characterized in that all Q values constituting the Q value
group are made the same.
[0012]
In this configuration, setting the Q value to be set to each PEQ to be the same simplifies the
setting processing and the calculation processing at the time of simulation, and can obtain the
differential value frequency characteristic after temporary correction at high speed.
[0013]
Further, the correction value setting means of the acoustic characteristic correction system of the
present invention determines that the difference from the desired acoustic characteristic is
minimum based on the fact that the maximum levels of the positive maximum and the negative
maximum after correction are minimum. It is characterized by doing.
[0014]
In this configuration, a correction pattern (combination of a set frequency, a gain, and a Q value)
in which the peak or dip at which the difference is at the maximum level is minimized with
respect to the desired acoustic characteristic is employed.
In this way, it is possible to determine a correction value that provides an acoustic characteristic
that is not largely different from the desired characteristic.
[0015]
Further, the correction value setting means of the acoustic characteristic correction system
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according to the present invention makes the judgment that the difference from the desired
acoustic characteristic is minimum based on the fact that the total sum of the differences over
the entire frequency band to be judged is minimum. It is characterized by
[0016]
In this configuration, a correction pattern is adopted in which the acoustic characteristic closest
to the desired characteristic in the entire frequency band to be determined is obtained.
Thereby, the optimal correction value can be determined in consideration of the entire frequency
band to be determined.
[0017]
Further, the correction value setting means of the acoustic characteristic correction system
according to the present invention determines that the difference from the desired acoustic
characteristic is minimized by using a partial frequency band having a predetermined frequency
width centered on the frequency of the positive maximum and the negative maximum. It is
characterized in that it is performed based on the fact that the sum of differences in groups is
minimized.
[0018]
In this configuration, the correction value of the equalizing means can be determined at high
speed while sufficiently reflecting the effect of the correction by setting the peripheral partial
frequency band including the peak and the dip as the determination target.
[0019]
Further, the correction value setting means of the acoustic characteristic correction system
according to the present invention is characterized in that the frequency band to be determined
is set based on at least one of the sound emission characteristic of the speaker and the sound
collection characteristic of the microphone.
[0020]
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In this configuration, the correction value is determined in consideration of the fact that the
sound emission characteristics of the speaker and the sound collection characteristics of the
microphone are not originally flat level characteristics on the frequency axis.
Thereby, the correction value can be determined without being influenced by the sound emission
characteristic of the speaker or the sound collection characteristic of the microphone.
[0021]
Further, the correction value setting means of the acoustic characteristic correction system of the
present invention is characterized in that the difference at the frequency of the positive
maximum and the negative maximum is weighted more heavily than the difference of the other
frequency bands.
[0022]
In this configuration, by weighting the frequency band of peaks and dips, it is possible to more
clearly reflect the effect of the peaks and dips when calculating the correction value.
[0023]
According to the present invention, since the Q value is easily set together with the set frequency
and gain of each PEQ, an acoustic characteristic correction system that achieves desired acoustic
characteristics with simple processing is realized without causing the user to perform
complicated operations. can do
[0024]
An acoustic characteristic correction system according to an embodiment of the present
invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the acoustic characteristic correction
system of the present embodiment, where (A) shows the configuration in the acoustic
characteristic correction setting mode, and (B) shows the configuration in the normal use mode.
FIG. 2A is a block diagram showing the configuration of the characteristic measurement unit 22,
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and FIG. 2B is a diagram showing the concept of frequency band division.
FIG. 3 is a block diagram showing the configuration of the equalizing processing unit 12.
As shown in FIG. 1A, in the acoustic characteristic correction setting mode, the acoustic
characteristic correction system according to this embodiment includes the CPU 11, equalizing
processing unit 12, D / A converter 13, power amplifier 14, speaker 15, microphone 16, An echo
processing unit 17, an A / D converter 18, a test sound source 21, and a characteristic
measurement unit 22 are provided.
[0025]
When the CPU 11 receives an input of voice characteristic correction setting start via the
operation unit (not shown) or the like, the CPU 11 gives a test sound generation start control to
the test sound source 21.
When receiving the test sound source generation start control, the test sound source 21
generates a signal set in advance or a signal for measuring acoustic characteristics (test signal)
designated by the CPU 11, for example, a white noise signal or a pink noise signal.
The D / A converter 13 converts the acoustic characteristic measurement signal in digital form
into an analog signal, and supplies the analog signal to the power amplifier 14.
The power amplifier 14 amplifies the acoustic characteristic measurement signal at a
predetermined amplification factor set in advance or designated by the CPU 11 and gives the
amplified signal to the speaker 15, and the speaker 15 measures the acoustic characteristic
measurement in the room where the acoustic characteristic is to be measured. It emits noise. For
example, when measuring the acoustic characteristic of a karaoke box, the sound by the signal
for acoustic characteristic measurement is emitted from the speaker 15 installed in the karaoke
box.
[0026]
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The microphone 16 is installed at a preset position in the same room as the speaker 15. For
example, in a karaoke box, the singer is usually installed at a standing position. The microphone
16 picks up the sound according to the acoustic characteristic measurement signal emitted from
the speaker 15 and gives it to the echo processing unit 17. The echo processing unit 17 adds an
echo preferred by the singer in the normal use mode described later, but outputs the echo to the
A / D converter 18 without performing the echo process in the acoustic characteristic correction
setting mode. The A / D converter 18 converts the sound picked up by the microphone 16 from
an analog format to a digital format, and supplies it to the characteristic measurement unit 22.
[0027]
Characteristic measurement unit 22 detects signal levels of partial frequency bands FB1 to FBm
obtained by dividing measurement frequency range FZ set in advance by a predetermined
number m, and outputs the signal levels to CPU 11. Specifically, partial frequency bands FB1 to
FBm are obtained by dividing measurement frequency range FZ corresponding to the frequency
band to be measured, which is set in advance from the speaker characteristics, microphone
characteristics, etc., into m in frequency bands equally spaced on the logarithmic axis, for
example It consists of a band and is set to FB1, FB2, ... FBm sequentially from the low band side.
The characteristic measurement unit 22 includes band pass filters (BPFs) 221, 222 to 22 m for
the number m of partial frequency bands, and signal level detection units 231, 232 to 23 m for
detecting signal levels in respective partial frequency bands. . The BPFs corresponding to the
respective partial frequency bands and the signal level detection unit are connected in series, and
the series circuit of the BPF for each partial frequency band and the signal level detection unit is
connected in parallel. For example, specifically, the FB1 band BPF 221 for the first partial
frequency band FB1 and the FB1 signal level detection unit 231 are connected in series to form
an FB1 signal detection serial circuit. Similarly, the FB2 band BPF 222 for the second partial
frequency band FB2 and the FB2 signal level detection unit 232 are connected in series to form
an FB2 signal detection series circuit, and the FBm band BPF 22m for the mth partial frequency
band FBm The FBm signal level detection unit 23m is connected in series to form an FBm signal
detection series circuit. Then, such a series circuit group for detecting the FBm signal is
connected in parallel between the A / D converter 18 and the CPU 11. With such a configuration,
the collected sound signal input from the A / D converter 18 is decomposed into the respective
band components by each of the BPFs 221 to 22m. The partial frequency band component signal
generated by each of the BPFs 221 to 22m is level-detected by each of the signal level detection
units 231 to 23m, and this level value is output to the CPU 11 together with partial frequency
band information. Further, the characteristic measurement unit 22 includes a full band signal
level detection unit 230 that detects the signal level in the measurement frequency range FZ. The
all-band signal level detection unit 230 is connected in parallel to each series circuit, detects the
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signal level of the sound collection signal input from the A / D converter 18, and outputs the
signal level value to the CPU 11 as an original signal level value.
[0028]
The CPU 11 normalizes the level value of each partial frequency band component signal with the
original signal level value. The CPU 11 compares, in each partial frequency band, the level value
of the normalized partial frequency band signal (normalized partial band signal level) with the
normalized desired acoustic characteristic previously stored in a memory (not shown). To detect
peaks and dips for desired acoustic characteristics. Here, the peak indicates a maximum (positive
maximum) in a portion where the normalized subband signal level is high compared to the
desired acoustic characteristic, and the dip indicates a low normalized subband signal level
compared to the desired acoustic characteristic Indicates a local minimum (negative maximum).
Although specifically described later, the CPU 11 detects the frequencies and levels of these
peaks and dips, sets an appropriate Q value, and simulates the temporary correction, thereby
making each parametric equalizer of the equalizing processing unit 12 PEQ) Set optimal
frequencies, gains and Q values of 121 to 12 n. Although the temporary correction result is
obtained by simulation in this embodiment, automatic re-measurement may be performed in a
real environment.
[0029]
The equalizing processing unit 12 is configured by multistage cascade connection of PEQs, and
in the example of FIG. 3, is configured by cascade connection of n PEQs 121 to 12n. Each of the
PEQs 121 to 12n is supplied with a correction parameter from the CPU 11, and performs
equalization processing with the correction parameter. As a result, the equalizing processing unit
12 which corrects the acoustic characteristic of the room in which the speaker 15 and the
microphone 16 are installed to the desired acoustic characteristic and emits the sound is formed.
[0030]
After such setting, in actual use (normal mode), an apparatus having a circuit configuration as
shown in FIG. 1B is used. In the following description, a case of a karaoke system in a karaoke
box is shown. Since the system configuration of the karaoke system is known, the detailed
description will be omitted.
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[0031]
As shown in FIG. 1B, in the normal use mode, the acoustic characteristic correction system of this
embodiment includes the CPU 11, equalizing processing unit 12, D / A converter 13, power
amplifier 14, speaker 15, microphone 16, echo processing The unit 17 includes an A / D
converter 18, a mixer 19, and a sound source 20.
[0032]
The sound source 20 is, for example, a known karaoke sound source, generates a music sound
signal of a digital format based on music data of karaoke music, and outputs the music sound
signal to the mixer 19.
The microphone 16 picks up the singing voice of the singer and outputs a pick-up signal to the
echo processing unit 17. The echo processing unit 17 applies echo processing to the collected
sound signal in accordance with the content of the echo instruction set separately by the singer
or the like, and outputs the result to the A / D converter 18. The A / D converter 18 converts the
collected sound signal after the echo processing into a digital form and outputs it to the mixer
19. The mixer 19 mixes the music sound signal and the sound collection signal after the echo
processing to generate a sound emission signal, and outputs the sound emission signal to the
equalizing processing unit 12.
[0033]
The equalizing processing unit 12 corrects the sound emission signal using the PEQs 121 to 12 n
set in the above-described acoustic characteristic correction mode, and outputs the sound
emission signal to the D / A converter 13. The D / A converter 13 converts the sound emission
signal (sound characteristic correction sound emission signal) whose acoustic characteristics
have been corrected from digital form into analog form and outputs the signal to the power
amplifier 14. The power amplifier 14 amplifies the acoustic characteristic correction sound
emission signal and gives it to the speaker 15, and the speaker 15 is driven based on the
amplified acoustic characteristic correction sound emission signal to emit sound into the room.
By using such a configuration, the music sound and the singing sound emitted from the speaker
15 are corrected to desired acoustic characteristics, and reach the singer holding the microphone
16. Thus, the singer can comfortably sing in the karaoke box.
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[0034]
Next, a specific method of acoustic characteristic correction will be described with reference to
FIGS. FIG. 4 is a table showing an example of the Q value pattern used when setting the Q value.
FIG. 5 is a diagram showing a system flow of the acoustic characteristic correction method. FIG. 6
is an explanatory diagram for explaining an acoustic characteristic correction method.
[0035]
In the acoustic characteristic correction system of this embodiment, when the acoustic
characteristic correction setting mode is executed, the characteristic measurement unit 22
detects the level value of the band component signal of each of the partial frequency bands FB1
to FBm (S101). In the example of FIG. 6, the level values of the band component signals of the
partial frequency bands FB1 to FBm of the characteristic curve 260 by the collected sound signal
(measurement signal) as shown in (A) are acquired.
[0036]
The CPU 11 makes a difference between the level value of each band component signal and each
band component signal level (desired signal level) of the desired acoustic characteristic to obtain
a difference value as an absolute value and a difference direction ("+" or "-"). Is calculated (S102).
In the example of FIG. 6, the difference value frequency characteristic curve 270 as shown in (B)
is acquired. At this time, based on the sound emission characteristic of the speaker 15 and the
sound collection characteristic of the microphone 16, the CPU 11 selects a predetermined
frequency region on the high frequency side of the entire frequency band FZ where sound
collection or sound emission is not complete and a predetermined frequency side. The calculation
is not performed for the frequency band. That is, the CPU 11 sets a frequency band in which
sound collection or sound emission is sufficient to the determination target frequency band FB,
and calculates a difference value and a difference direction in the determination target frequency
band FB. As a result, the correction value can be set without being influenced by the sound
release characteristic of the speaker 15 and the sound collection characteristic of the
microphone 16. Although the case where both the sound emission characteristic of the speaker
and the sound collection characteristic of the microphone have been taken into consideration has
been described, only one of them may be taken into consideration.
08-05-2019
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[0037]
The CPU 11 detects peaks and dips from the difference value and the difference direction of each
of the partial frequency bands FB1 to FBm (S103). That is, the CPU 11 extracts the maximum
value on the high level side from the desired acoustic characteristic in the frequency
characteristic of the difference value series and the minimum value on the low level side from the
desired acoustic characteristic, and the partial frequency band for each maximum value and
minimum value Associate and get. In the example of FIG. 6, the difference value frequency
characteristic 270 as shown in (B) is acquired, and the peaks M1, M3, M5, M7, M9 and dips M2,
M4, M6, M8 of the difference value frequency characteristic 270 are obtained. , M10 are
detected.
[0038]
The CPU 11 sorts the peaks and dips in descending order of the differential value (absolute
value) level, and sets the correction target peak and the correction target dip in descending order
of level (S104). At this time, the number of peaks and the number of dips to be corrected are set
based on the number of PEQs 121 to 12 n of the equalizing processing unit 12. In the following,
in order to simplify the description, the case where one PEQ is assigned to each of the peak and
the dip will be described. The example of FIG. 6 shows the case where the number of PEQs is 10,
and all the peaks and dips M1 to M10 can be corrected. In this case, all the peaks and dips M1 to
M10 are corrected. set to target.
[0039]
The CPU 11 acquires the level of the peak to be corrected and the level of the dip to be corrected,
and calculates a correction level composed of the opposite sign of the level. The CPU 11 acquires
the center frequency of the partial frequency band as the correction frequency based on the
partial frequency band information corresponding to the correction target peak and the
correction target dip (S106). In the example of FIG. 6, the reverse sign of the level of the peak /
dip M1 to M10 is used as the correction level, and the center frequency of each corresponding
partial frequency band is acquired as the correction frequency.
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[0040]
The CPU 11 sets a Q value for correction for each peak / dip. At this time, the CPU 11 stores in
advance a plurality of types of Q value patterns PQ (A) to PQ (E) as shown in FIG. 4, and reads
out the respective Q value patterns PQ (A) to PQ (E). Assign to each peak and dip. Note that
although an example in which five types of Q value patterns are set is described in this
description, more or less may be set according to the specification. In the example of FIG. 6, since
the peak / dip number is 10, each of the Q value patterns PQ (A) to PQ (E) consists of a
combination of 10 (n = 10) Q values, and the peaks And set the Q value of each Q value pattern
to dips M1 to M10. Then, after setting each Q value pattern, the CPU 11 performs simulation to
calculate a provisional correction frequency characteristic (S107). That is, the correction
characteristic is stored in advance for each combination of the Q value and the gain, and the CPU
11 reads the correction characteristic based on the combination of the set Q value and the gain,
and obtains the frequency characteristic of the acquired sound collection signal. Perform an
operation to make a pseudo correction.
[0041]
More specifically, the CPU 11 first reads out each Q value (QA1 to QA10) of the Q value pattern
PQ (A), sets it along with the set frequency and the correction level to each PEQ, and simulates
the frequency characteristic of the collected signal. Simulation to make corrections Next, each Q
value (QB1 to QB10 (n = 10)) of the Q value pattern PQ (B) is read out, and is set to each PEQ
together with the set frequency and the correction level to perform simulation. Such processing
is also performed on the Q-value patterns PQ (C) to PQ (E).
[0042]
The CPU 11 calculates the difference between the provisional correction frequency characteristic
by each of the Q value patterns PQ (A) to PQ (E) and the desired acoustic characteristic set in
advance, as shown in FIGS. 6 (C) to (G). The corrected difference value frequency characteristics
271 to 275 by the Q value patterns PQ (A) to PQ (E) are acquired (S108). At this time, the
corrected difference value frequency characteristics 271 to 275 are obtained for each partial
frequency band and arranged on the frequency axis as in the above-described difference value
calculation.
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[0043]
The CPU 11 compares the corrected difference value frequency characteristics 271 to 275
(S109). Specifically, for example, the CPU 11 acquires the absolute value of the difference level of
each partial frequency band of each of the corrected difference value frequency characteristics
271 to 275, and compares the sum of the absolute values of the difference levels. In addition, for
example, the CPU 11 obtains the absolute value of the difference level of each partial frequency
band of each of the corrected difference value frequency characteristics 271 to 275, and
compares the absolute value of the maximum difference value level.
[0044]
The CPU 11 detects a characteristic that minimizes the difference determination amount based
on such a comparison result, and acquires a corresponding Q-value pattern (S110). Here, the
difference determination amount is a sum of absolute values of difference levels or an absolute
value of a maximum difference value level. That is, when using the sum of the absolute values of
the difference value levels, the CPU 11 corrects the difference value frequency characteristics
after correction with the total sum of the absolute values of the difference value levels of the
corrected difference value frequency characteristics 271 to 275 being minimum (FIG. In the
example of (1), the post-correction difference value frequency characteristic 274) is selected, and
the corresponding optimum Q-value pattern (in the example of FIG. 6, the Q-value pattern PQ (D))
is detected. When using the absolute value of the maximum difference value level, the CPU 11
obtains the absolute values DM (A) to DM (E) of the maximum difference value levels of the
corrected difference value frequency characteristics 271 to 275. Do. The CPU 11 selects the
absolute value (DM (D) in the case of FIG. 6) of the maximum difference value level which is
minimized, and the corresponding optimum Q value pattern (in the example of FIG. 6, the Q
value) The pattern PQ (D) is detected.
[0045]
When the CPU 11 detects the optimum Q value pattern, it generates a parameter list including
the Q value and the corresponding set frequency and correction level to be given to each PEQ
(S111). The CPU 11 transmits the corresponding parameter to each of the cascaded PEQs 121 to
12n of the equalizing processing unit 12 based on the generated parameter list (S112).
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[0046]
Each of the PEQs 121 to 12n of the equalizing processing unit 12 performs equalizing
processing based on the given parameters. Thereby, the acoustic environment of the desired
acoustic characteristic set in advance can be realized in the room (system from speaker to
microphone). Furthermore, by performing such processing, setting of the Q value at which
optimum correction characteristics can be obtained can be easily performed without performing
complicated operations and the like.
[0047]
In the above description, each Q value constituting the Q value pattern is set appropriately, but
all Q values constituting one Q value pattern may be set to the same value. As a result, simulation
can be performed more easily, and an acoustic environment close to a desired acoustic
characteristic can be realized faster.
[0048]
In the above description, one PEQ is assigned to one peak and dip, but the present invention is
not limited thereto. Two consecutive peaks may be assigned according to the shape of difference
value frequency characteristic 270. It is not necessary to make the number of peaks and dips
equal to the number of PEQs, such as allocating three PEQs. In this case, the set frequency and
the correction level described above may be set according to the shape of the difference value
frequency characteristic 270.
[0049]
In the above description, the difference determination amount is compared in the entire
determination target frequency band FB as an example, but the determination is performed with
reference to only the result in the partial frequency region including the predetermined
frequency width including the peak and the dip. You may For example, instead of calculating the
sum of the absolute values of the difference levels in the entire determination target frequency
band FB, calculation may be performed only in a plurality of partial frequency regions including
each peak and dip. As a result, the calculation range of the sum is narrowed, and the optimum Q-
08-05-2019
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value pattern can be selected more quickly.
[0050]
Also, in the above description, an example is given in which the difference level is uniformly
summed over the entire determination target frequency band FB, but the difference level
between the peak and dip partial frequency bands is heavier than other partial frequency bands.
The weighting may be performed to perform the summation operation. By performing such a
weighted sum operation, it is possible to select the optimum Q-value pattern more accurately, in
consideration of the correction results at the peak and the dip.
[0051]
Also, in the above description, an example of performing simulation by setting Q values
simultaneously for all PEQs is shown, but simulation is performed by setting a plurality of Q
values composed of different values to one of PEQs, A method may be used in which the
optimum Q value is set for each PEQ by calculating the difference level at the corresponding
peak and dip. FIG. 7 is a flow chart of a method of setting an optimum Q value for each PEQ.
[0052]
The method of setting the optimum Q value for each PEQ is the same as the method of
performing simulation by setting each Q value of the Q value parameter to all the PEQs described
above up to S106, and the description up to S106 is omitted.
[0053]
After determining the correction frequency and the correction level of each peak and dip, the
CPU 11 sorts the correction target peak and the correction target dip in descending order of the
absolute value of the correction level (S117).
The CPU 11 individually associates each PEQ constituting the equalizing processing unit 12 with
the sorted correction target peak and correction target dip (S118). For example, the CPU 11
associates the correction target peak and the correction target dip from the PEQ in the first stage
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in the sort order. Hereinafter, the case where PEQ is determined in this order is shown.
[0054]
The CPU 11 has a parameter list of Q values as shown in FIG. 4 and provides the PEQ of the first
stage with the set frequency and correction level for the highest correction target peak
(correction target dip). Q values QA1 to QE1 of patterns PQ (A) to PQ (E) are sequentially set. The
CPU 11 performs simulation for each of the set Q values QA1 to QE1, and detects a Q value that
minimizes the difference level in the partial frequency band corresponding to the corresponding
correction target peak (correction target dip) (S119 → S120) .
[0055]
The CPU 11 continues performing the optimum Q value setting process for such PEQ
sequentially for each PEQ (S121: N → S119), and when the optimum Q value setting process for
all PEQs is completed, generates a parameter list for the equalizing processing unit (S121: Y →
S111). The CPU 11 transmits the corresponding parameter to each of the cascaded PEQs 121 to
12n of the equalizing processing unit 12 based on the generated parameter list (S112).
[0056]
Even with such a method, the parameters of each PEQ of the equalizing processing unit can be
easily set.
[0057]
By the way, in the above description, a case is shown where components are different in each
mode, but it may be an acoustic characteristic correction system having the configurations of
FIGS. 1 (A) and 1 (B) at the same time.
That is, a circuit switching unit such as a switch may be provided, and the acoustic characteristic
correction setting mode and the normal use mode may be selectively used by switching
processing of the circuit switching unit.
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[0058]
It is a block diagram which shows the structure of the acoustic characteristic correction system
of this embodiment. It is a block diagram which shows the structure of the characteristic
measurement part 22, and a figure which shows the division | segmentation concept of a
frequency band. FIG. 2 is a block diagram showing the configuration of an equalizing processing
unit 12; It is the table which showed the example of the Q value pattern which is used when
setting the Q value. It is a figure which shows the system flow of the acoustic characteristic
correction method. It is an explanatory view in order to explain an acoustic characteristic
amendment method. It is a flowchart of the method of setting the optimal Q value for every PEQ.
Explanation of sign
[0059]
11-CPU, 12-equalizing processor, 13-D / A converter, 14-power amplifier, 15-speaker, 16microphone, 17-echo processor, 18-A / D converter, 19-mixer, 20-sound source , 21-Test sound
source, 22-Characteristic measurement unit
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19
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