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JP2008227681

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DESCRIPTION JP2008227681
The present invention provides an acoustic characteristic correction system capable of effectively
realizing acoustic characteristics that do not generate a clip of a signal and cause no discomfort
to the user. SOLUTION: In this acoustic characteristic correction system, sound emitted from a
speaker 15 is collected by a microphone 16 to acquire the present acoustic characteristic 250.
When detecting the dip, the CPU 11 calculates a difference value with the desired acoustic
characteristic 260 in the partial frequency band of the dip, and determines whether the
difference value is less than a lower limit threshold value previously set for each partial
frequency band. If the difference value is the lower limit threshold, the CPU 11 sets the
calculated difference value as the lower limit threshold. The CPU 11 sets a correction value based
on the difference value subjected to such measurement processing, and sets an initial parameter
to the equalizing processing unit 12. The equalizing processing unit 12 corrects the sound
emission signal based on the given initial parameter. [Selected figure] Figure 5
Acoustic characteristic correction system
[0001]
The present invention relates to a frequency characteristic correction system which measures
transmission characteristics from a speaker to a listener position and corrects the transmission
characteristics to a desired characteristic.
[0002]
Currently, there are various environments where ordinary people can enjoy music casually.
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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 sets an equalizer to attenuate a
signal level in a frequency band that becomes howling, while Patent Document 2 performs
correction of audio characteristics, but the characteristic after correction is extreme. In order to
prevent this, the operator appropriately sets the correction level and the correction frequency
band. JP-A-8-84394 JP-A-7-38988
[0003]
However, although the acoustic characteristic correction system of the above-mentioned patent
document 1 is easy to configure the processing calculation by using the IIR filter, it only reduces
the signal level for the purpose of suppressing the howling, The signal level can not be enhanced
if there is a dip in the acoustical properties. Further, Patent Document 2 can both reduce and
enhance the signal level, but it is difficult to set an appropriate value because it is performed by
the user's operation input. Furthermore, the upper limit value and the lower limit value of the
correction level are set in order to prevent the generation of a duller acoustic characteristic by
such manual input, but the upper limit value and the lower limit value are uniquely set. It is set.
[0004]
Therefore, an object of the present invention is to provide an acoustic characteristic correction
system capable of performing more detailed setting to prevent an increase in the occurrence of
clipping of a waveform due to excessive enhancement of signal level by dip correction. It is.
[0005]
(1) The present invention relates to an acoustic characteristic correction system that corrects the
acoustic characteristic of a system in which a sound emitted from a speaker is propagated to a
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2
microphone position to a desired acoustic characteristic in a predetermined space in which a
microphone and a speaker are installed. It is a thing.
The acoustic characteristic correction system according to the present invention divides the
sound pickup signal of the microphone into a plurality of frequency band components, calculates
a difference value from the desired acoustic characteristic in each frequency band component,
and calculates a correction characteristic based on the difference value. A correction
characteristic calculation means is provided. Then, the correction characteristic calculation
means sets the lower limit threshold individually for each frequency band component when
calculating the difference value, and sets the difference value with respect to the frequency band
component for which the difference value less than the lower limit threshold is calculated as the
lower limit threshold. , Is characterized.
[0006]
In this configuration, for example, the sound pickup signal of the microphone is divided into a
plurality of partial frequency bands by an equalizing unit in which a plurality of PEQs
(parametric equalizers) are cascaded, and the signal level of each partial frequency band
component is adjusted. Correct the acoustic characteristics. The adjustment of the signal level
includes a correction to increase the signal level (intensification correction) and a correction to
reduce the signal level (suppression correction). In the acoustic characteristic correction system
of the present invention, partial frequency band components to be subjected to the enhancement
correction are calculated. The lower limit value is set to the difference value between the signal
level of the collected signal to be taken into consideration and the signal level of the desired
acoustic characteristic. The lower limit value is not unique for all bands, but is set for each partial
frequency band, and can be set finely when setting the correction level. By setting the lower limit
value of the difference value in this manner, the upper limit of the enhancement correction is set.
As a result, it is possible to prevent so-called clipping in which the signal is amplified and the
signal waveform is distorted due to excessive enhancement correction beyond the appropriate
dynamic range.
[0007]
(2) The correction characteristic calculation means of the acoustic characteristic correction
system according to the present invention is characterized in that the absolute value of the lower
limit threshold is set gradually larger from the low band side to the high band side.
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[0008]
In this configuration, as a specific example of the setting of the lower limit value, the sound
pressure level on the low frequency side becomes high between 20 Hz and 20 kHz in a general
case where a person sings as in a karaoke box, Since the sound pressure level on the high band
side tends to be low, the correction low limit on the low band side is set higher (lower if it is an
absolute value level), and the correction low limit on the high band side is low (absolute level If
this is the case, set it to
As a result, the margin of the correction on the high band side is not affected by the setting on
the low band side. For example, even if a difference value exceeding the lower limit value of the
low band occurs on the high band side, the difference value on the high band side If it does not
reach, the correction level can be set according to the difference value. As a result, the correction
level can be set in more detail with the limitation of the enhancement correction.
[0009]
(3) Further, the correction characteristic calculation unit of the acoustic characteristic correction
system according to the present invention has an upper limit to the frequency range in which the
correction for raising the frequency band component is performed when the frequency band
component is lower than the desired acoustic characteristic. Alternatively, at least one of the
lower limits is set.
[0010]
In this configuration, in the acoustic characteristic, there is a region where the signal level
decreases at the low band side and the high band side end from the constant signal level part of
the middle band due to the speaker characteristic etc. which will be described later.
And these reduced regions have less influence on the auditory characteristics of the singer etc.
Therefore, according to the present invention, more effective correction levels can be set by
excluding the area in which the signal level decreases.
[0011]
(4) Further, the correction characteristic calculation unit of the acoustic characteristic correction
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system of the present invention is characterized in that the upper limit or the lower limit of the
frequency range is set based on at least the sound emission characteristic of the speaker device.
[0012]
In this configuration, the characteristic of the speaker apparatus having a large influence is
referred to as a specific upper limit and lower limit setting.
[0013]
According to the present invention, it is possible to prevent the occurrence of a clip due to the
correction by setting the restriction on the correction in the enhancement direction without
setting the restriction on the correction in the suppression direction. Because it is possible to set
to, it is possible to achieve acoustic characteristics closer to the desired acoustic characteristics
while preventing clipping.
[0014]
An acoustic characteristic correction system according to a first 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,
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.
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[0015]
When the CPU 11 receives an input of acoustic characteristic correction setting start via the
operation unit (not shown) or the like, the CPU 11 gives the test sound source 21 control to start
test sound generation. When the test sound source generation control is received, the test sound
source 21 generates a signal set in advance or an acoustic characteristic measurement 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 installed in the karaoke box.
[0016]
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.
[0017]
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, the partial frequency bands FB1
to FBm divide the measurement frequency range FZ corresponding to the frequency band to be
measured, which is set in advance from the speaker characteristics, the microphone
characteristics, etc., into m in frequency bands equally spaced on the logarithmic axis, for
example , And are set to FB1, FB2,... FBm in order from the low band side. The characteristic
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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 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.
[0018]
The CPU 11 normalizes the level value of each partial frequency band component signal with the
original signal level value. The CPU 11 sets each of the level value of the normalized partial
frequency band signal (normalized partial band signal level) and the normalized desired acoustic
characteristic (desired frequency characteristic) stored in advance in a memory (not shown). The
difference is calculated in the partial frequency band to calculate the difference value, and the
peak and the dip for the desired acoustic characteristic are detected. Here, a peak indicates a
portion where the difference value is + , that is, a portion where the normalized subband
signal level is higher than the desired acoustic characteristic, and a dip is where the difference
value is − , that is, It shows a portion where the normalized subband signal level is low
compared to the desired acoustic characteristic. Specifically, when detecting a dip, the CPU 11
determines whether the difference value of the partial frequency band of the dip is less than a
lower limit threshold level ThL set in advance. If the difference value is less than the lower limit
threshold level ThL, the CPU 11 sets the difference value to the lower limit threshold ThL. The
CPU 11 calculates the correction value by taking the opposite sign of the difference value
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calculated and set as described above, and sets the correction parameter of each of the PEQs 121
to 12 n of the equalizing processing unit 12 based on the correction value. At this time, the CPU
11 may set the enhancement direction correction frequency range for enhancing the dip signal
level and the suppression direction correction frequency range for suppressing the peak signal
level to be different. In this case, the CPU 11 mainly takes into account the sound emission
characteristics of the speaker 15 and takes into account the sound collection characteristics of
the microphone 16 and determines the frequency region of the predetermined width of the high
frequency side end and the predetermined low frequency side end of the measurement frequency
range FZ. Set to prohibit enhancement direction correction in the frequency domain of width.
That is, the CPU 11 sets the enhancement direction correction frequency range narrower than
the suppression direction correction frequency range. As a result, it is possible to prevent the
unreasonable enhancement direction correction in the area where the sound emission and sound
collection level are originally low, and to perform effective correction in the area where the
correction is necessary.
[0019]
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. Thus, it is possible to form the equalizing
processing unit 12 that 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.
[0020]
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.
[0021]
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.
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[0022]
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.
[0023]
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. At this time, as described above, by setting the lower limit of the difference value in
calculating the correction level, the enhancement direction correction is limited. For this reason,
although the signal level becomes lower than the desired acoustic characteristic near the partial
frequency band of dip occurrence, the possibility of occurrence of clipping is low. This can
prevent clipping of the signal due to unreasonable enhancement correction.
[0024]
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Next, a specific method of acoustic characteristic correction will be described with reference to
FIGS.
[0025]
FIG. 4 is a diagram showing a system flow of the acoustic characteristic correction method by the
acoustic characteristic correction system.
FIG. 5 is a frequency characteristic diagram for explaining the method and concept of acoustic
characteristic correction. In each figure, (A) shows the normalized frequency characteristic 250
of the collected signal when the white noise is emitted from the speaker 15 and collected by the
microphone 16, and (B) shows the frequency characteristic of the collected signal. The peak and
dip concept based on 250 and the preset desired acoustic characteristic 260 and the frequency
characteristic 270 of the lower threshold are shown, (C) shows the frequency characteristic
outline of the difference value level, (D) shows the correction value The frequency characteristic
outline of the level is shown, and (E) shows the frequency characteristic of the acoustic
environment (corrected acoustic environment characteristic) after correction using the correction
value shown in (D).
[0026]
FIG. 6 is a diagram showing the frequency characteristic of the lower threshold ThL, (A) is a
frequency characteristic diagram when the lower threshold ThL is different for each partial
frequency band, and (B) is a constant frequency characteristic of the lower threshold ThL. It is a
frequency characteristic figure in the case.
[0027]
In the acoustic characteristic correction system, 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).
Thereby, frequency characteristics 250 as shown in FIGS. 5A and 5B are obtained.
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[0028]
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. 5B, the partial frequency band components of the frequency characteristic
250 of the measured sound pickup signal level and the desired acoustic characteristic 260 set in
advance are differentiated. Thereby, the frequency characteristic 350 of the difference value
level as shown in FIG. 5 (C) is obtained. The CPU 11 detects the peak and dip of the frequency
characteristic of the difference value sequence 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.
[0029]
As shown in FIG. 5, the CPU 11 adopts the difference value level in a frequency band FB which is
narrower than the measurement frequency band FZ and whose characteristics are relatively
stable. The frequency band FB to be set is mainly set on the basis of the sound emission
characteristic of the speaker 15 and on the basis of the sound collection characteristic of the
microphone 16 and the high frequency side end of the measurement frequency band FZ
originally having a low sound emission level and sound collection level. The predetermined
frequency range of the unit and the predetermined frequency range of the low band side end
portion are not used for the calculation of the difference value, the calculation of the correction
value, and the correction. In this way, it is possible to prevent unnecessary correction in the area
where the signal level tends to be low originally. However, at this time, the difference value in the
measurement frequency band FZ may be calculated, and only the correction of the suppression
direction may be performed. By performing such correction, the useless correction of the
direction of correction is performed. It is possible to reliably prevent clipping in the entire
measurement frequency band FZ. In the following description, in order to simplify the
description, the case where the difference value is calculated in the frequency band FB will be
described. For example, in the case of FIG. 5, the dips 271 and 273 and the peak 272 are
detected.
[0030]
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When the CPU 11 detects a peak (S104: Peak), the CPU 11 uses the difference value level as it is
(S106), and calculates a correction value composed of the reverse sign level of the difference
value level (S108).
[0031]
On the other hand, when detecting a dip (S104: Dip), the CPU 11 determines whether the
difference value level is less than the lower limit threshold ThL set in advance.
Specifically, as shown in FIG. 6A, a lower threshold ThL having a frequency characteristic is set in
advance and stored in a memory (not shown). The CPU 11 reads the lower limit threshold ThL
corresponding to the partial frequency band of each dip, and compares it with the difference
value level of the dip.
[0032]
At this time, setting the lower limit threshold ThL to the frequency characteristic enables detailed
setting of correction. For example, as shown in FIG. 6A, the absolute value of the lower limit
threshold on the low band side is set low, and the absolute value of the low limit threshold on the
high band side is set high. By performing such a setting, the correction upper limit value in the
low tone range in the frequency band FB having a relatively high sound pressure and many
partial frequency components becomes low, and in a high tone region having a relatively low
sound pressure and few partial frequency components The correction upper limit of is increased.
This limits the amount of enhancement in the low range where the signal level is high and
clipping is likely to occur, and alleviates the limitation of the enhancement in the high range
where the signal level is low and the possibility of clipping is relatively small. it can. Thereby,
since the restriction on the high frequency side is not restricted by the restriction on the low
frequency side, an acoustic environment closer to desired acoustic characteristics can be realized
while maintaining the function of preventing clipping of the signal. The addition / subtraction
threshold value ThL may be a flat frequency characteristic 370 'as shown in FIG. 6B. By setting
such a characteristic, it is possible to set the following difference value level and correction value
level. It will be easier.
[0033]
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If the difference value level is equal to or higher than the lower limit threshold ThL (S105: N), the
CPU 11 uses the difference value level as it is (S106), and calculates a correction value composed
of the opposite sign level of the difference value level (S108). Furthermore, when the CPU 11
detects a dip and detects that the difference value level is less than the lower threshold ThL
(S105: Y), the difference value level is replaced with the signal level of the lower threshold ThL
(S107), and the correction value is corrected. Is calculated (S108). If this is applied to the
example of FIG. 5 and described with reference to the lower threshold characteristic 270 (370),
the difference value level of the dip 271 is lower than the lower threshold ThL 271 of the
corresponding partial frequency band. Is set to the lower limit threshold ThL 271 of the
corresponding partial frequency band. On the other hand, since the difference value level of the
dip 273 is higher than the lower limit threshold ThL 273 of the corresponding partial frequency
band, the CPU 11 uses the difference value level for the dip 273 as it is.
[0034]
Such processing is performed on all detected peaks and dips, and the CPU 11 calculates
correction values for all peaks and dips. Thereby, the correction value level group as shown in
FIG. 5D is obtained. The CPU 11 generates a parameter list to be given to the equalizing
processing unit 12 from the calculated correction value group (S109). Here, the parameter list
indicates an initial parameter group of each of the PEQs 121 to 12n constituting the equalizing
processing unit 12. That is, based on each correction value and the corresponding partial
frequency band FB, the setting frequency (f), gain (G) and Q value of each PEQ are set
sequentially, and the parameter list is obtained from these set parameters. It is formed. The CPU
11 transmits corresponding initial parameters to the cascaded PEQs 121 to 12 n of the
equalizing processing unit 12 based on the generated parameter list (S110).
[0035]
Each of the PEQs 121 to 12n of the equalizing processing unit 12 performs equalizing
processing based on the provided initial parameters.
[0036]
As a result, it is possible to realize an acoustic environment close to a preset desired acoustic
characteristic in a room (system from speaker to microphone).
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At this time, the lower limit threshold is provided for deep dips of the level, and the upper limit of
the correction value is set, thereby faithfully reproducing the desired acoustic characteristic as
shown by the frequency characteristic 251 of FIG. 5 (E). It will not be possible. However, since it
is considered that too deep dip may be generated accidentally, if this dip is eliminated and the
signal level of the corresponding partial frequency band becomes high, the correction that
faithfully reproduces is performed. It is also conceivable that a clip may occur. In view of this, by
setting the lower limit to the difference value level, that is, by setting the upper limit to the
correction value, the faithful reproduction of the acoustic environment can not be achieved, but
the clip of the signal is surely given without giving a great discomfort. To create an acoustic
environment close to the desired acoustical characteristics.
[0037]
In the above description, different components are shown 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.
[0038]
Further, in the above description, the equalizing processing unit 12 is configured by PEQs
connected in cascade, but the equalizing processing unit 12 may be formed by an analog
equalizer group connected in parallel.
[0039]
When the equalization processing unit is configured by these circuits, gain adjustment for each
partial frequency band of the signal is performed only when the equalization processing is
performed. Therefore, when non-processing setting is performed, characteristics by each circuit
element or Since the number of stages in which the sound quality degrades is reduced, it is
possible to obtain better sound quality in addition to the effects of the present invention
described above.
[0040]
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Further, in the acoustic characteristic correction system of the present invention, the sound
collection characteristic of the microphone 16 is obtained in advance and given to the CPU 11,
the CPU 11 equalizes the correction parameter taking into account the sound collection
characteristic of the microphone 16 as well. It can be set to the processing unit 12.
As a result, the acoustic characteristics of the system from the speaker 15 to the singer singing
with the microphone 16 can be set to a desired characteristic, and a more optimal acoustic
environment for the singer can be realized.
[0041]
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 a figure which shows
the system flow of the acoustic characteristic correction method by an acoustic characteristic
correction system. FIG. 6 is a frequency characteristic diagram for explaining a method and
concept of acoustic characteristic correction. It is a figure which shows the frequency
characteristic of lower limit threshold value ThL.
Explanation of sign
[0042]
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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