JP2003168940

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DESCRIPTION JP2003168940
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
acoustic control apparatus for adjusting the acoustic characteristics of reproduced audio in an
audio reproduction apparatus, and more particularly to a so-called loudness function which
corrects high and low frequency signal levels according to volume setting. The present invention
relates to a sound adjustment device having
[0002]
2. Description of the Related Art Many sound reproduction devices have built-in sound
adjustment devices having a so-called loudness function, a sound quality adjustment function for
adjusting the sound quality, and an audibility characteristic correction function for correcting
human audibility characteristics at low volume. ing. Recently, digital signal processing technology
has been developed, and sound adjustment has come to be performed by digital arithmetic
processing by a digital signal processor (DSP).
[0003]
However, the signal processing of the sound quality adjustment and the auditory characteristic
correction is performed independently of each other. Therefore, each operation process is
required, and the number of operation steps to be processed by the DSP becomes enormous.
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Therefore, high speed operation process is required, and the DSP becomes expensive.
[0004]
The present invention has been made in view of such problems, and aims to realize an acoustic
adjustment device capable of performing both of the sound quality adjustment and the auditory
characteristic correction even if the DSP is a relatively low-performance DSP. There is.
[0005]
SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in order to
solve the above-mentioned problems, the acoustic adjusting device (1) according to the present
invention performs digital arithmetic processing on the acoustic signal based on the acoustic
characteristic control signal from the control unit. An acoustic adjustment device including a
digital arithmetic processing unit for adjusting the acoustic characteristics, wherein the control
unit performs the acoustic characteristic control signal from the sound quality setting value from
the sound quality setting unit and the volume setting value from the volume setting unit. It is
characterized in that it comprises an acoustic characteristic calculation unit which calculates and
outputs it to the digital calculation processing unit.
[0006]
According to the sound adjustment device (1), since the control unit calculates the sound
characteristic control signal according to the sound quality setting value and the volume setting
value and outputs the signal to the digital calculation processing unit, the calculation in the
digital calculation processing unit The processing is good with one system of arithmetic
processing (usually, two systems of an operation based on the sound quality setting value and an
operation based on the volume setting value are required), and the total amount of operation is
reduced.
Therefore, it is possible to realize an acoustic adjustment device capable of performing both of
the sound quality adjustment and the auditory sense characteristic correction even with the use
of an arithmetic element (DSP) having a relatively low processing capability, and to reduce the
cost.
[0007]
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Further, according to the sound adjustment device (2) of the present invention, in the sound
adjustment device (1), the sound characteristic calculation unit calculates sound quality control
values based on the sound quality setting value; The sound quality control value calculated by
the calculation means is characterized by comprising correction means for performing signal
level correction of a high range and a low range according to the volume setting value.
According to the above-described sound adjusting device (2), since the signal levels of the bass
and treble band are adjusted according to the volume adjustment amount, it is possible to correct
the sound signal according to the human auditory sense characteristic.
[0008]
Further, according to the sound adjustment device (3) of the present invention, in the sound
adjustment device (1) or (2), the sound characteristic calculation unit calculates sound quality
control values based on the sound quality setting value. And Q value correction means for
correcting the Q value corresponding to the volume setting value in the level adjustment in the
high range and the low range to the sound quality control value calculated by the sound quality
calculation means. There is. According to the above-described sound adjusting device (3), the Q
value (sharpness) of signal level correction in the bass and treble band is corrected according to
the volume adjustment amount, that is, the spread of the increase and decrease of the signal level
in the frequency axis direction As a result, the amount of energy of the sound signal in the low
tone range and the high tone range is adjusted, and as a result, the sound signal can be corrected
according to the human auditory sense characteristic.
[0009]
Further, in the sound adjustment device (4) according to the present invention, in any one of the
sound adjustment devices (1) to (3), the sound characteristic calculation unit calculates a sound
quality control value based on the sound quality setting value. A sound quality calculation means,
and a center frequency correction means for correcting the sound quality control value
calculated by the sound quality calculation means according to the volume setting value in level
adjustment in the high range and the low range. It is characterized by According to the sound
adjustment device (4) described above, the central frequency of the signal level correction in the
low and high frequency ranges is corrected according to the volume adjustment amount, that is,
the frequency of increase and decrease of the signal level is adjusted. The influence of the level
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on humans changes (the more the frequency changes to the midrange, the same level change
amount is felt to change significantly), and as a result, the acoustic signal can be corrected
according to the human hearing characteristic.
[0010]
Further, in the sound adjustment device (5) according to the present invention, in any one of the
sound adjustment devices (1) to (4), the sound characteristic calculation unit calculates a sound
quality control value based on the sound quality setting value. Sound quality calculation means;
and turnover frequency correction means for correcting the sound quality control value
calculated by the sound quality calculation means according to the volume setting value in level
adjustment in the high range and low range. It is characterized by According to the sound
adjustment device (5) described above, the turnover frequency of the signal level correction in
the low range and the high range is corrected according to the volume adjustment amount, that
is, the frequency range of increase and decrease of the signal level is adjusted. The influence of
the signal level on humans changes (the amount of acoustic energy greatly changes as the
adjustment frequency range expands), and as a result, it is possible to correct the acoustic signal
according to the human auditory sense characteristic.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be
described below with reference to the drawings. FIG. 1 is a block diagram showing the
configuration of the sound adjustment apparatus according to the embodiment. The acoustic
signal source 1 is a device that outputs an acoustic signal, and includes, for example, a CD player,
a cassette player, a radio receiver, and the like. An acoustic signal from the acoustic signal source
1 is input to a DSP (digital signal processor) 2 and its acoustic characteristics are adjusted by
digital arithmetic processing. Control data for determining the content of the arithmetic
processing, that is, for determining the acoustic characteristic to be applied to the acoustic signal
is given to the DSP 2 from the control unit 4. The input signal to the DSP 2 must be a digital
signal, but if the acoustic signal source 1 outputs an analog signal, it is converted to a digital
signal by an analog / digital conversion circuit (not shown) and then input. ing.
[0012]
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An acoustic signal subjected to digital arithmetic processing in the DSP 2 is converted into an
analog signal by a digital-analog conversion circuit (not shown) and output to an audio volume
adjustment circuit 11 constituted by an electronic volume. The volume adjustment circuit 11
attenuates the acoustic signal based on the volume control signal from the control unit 4 and
outputs it to the power amplifier 3 in the latter stage, and the power amplifier 3 amplifies the
power of the acoustic signal and outputs it to the speaker 10 The audio output is performed from
10 on.
[0013]
The control unit 4 is constituted by a microcomputer (microcomputer) 6, a memory 5 including a
ROM for storing data, a RAM, and the like, and controls each part of the sound adjustment
apparatus. Further, the control unit 4 includes a volume adjustment operation unit 9 (configured
by a volume) for setting a volume, and an equalizer setting unit 8 (slide volume provided for each
adjustment frequency) for setting a frequency characteristic. And the like, and the volume setting
value and the sound quality setting value are input to the control unit 4. Then, the control unit 4
calculates acoustic characteristics based on the input sound volume setting value and sound
quality setting value, and calculates control data to be output to the DSP 2 from the calculated
acoustic characteristics.
[0014]
As a result, the DSP 2 performs arithmetic processing so that the acoustic signal has a
predetermined acoustic characteristic. The memory 5 contains controllable acoustic
characteristics and control data corresponding to all types (control data for all combinations of
adjustment frequency and its level increase / decrease amount so that the characteristic
frequency and level increase / decrease amount can be selected in several steps) A
predetermined number of combinations are stored, and when the acoustic characteristic is
determined, control data corresponding to the characteristic value is read from the memory 5
and output to the DSP 2. Then, the DSP 2 performs arithmetic processing on the acoustic signal
based on the control data, and the acoustic signal of the corresponding acoustic characteristic is
reproduced from the speaker 10. Therefore, the DSP 2 performs sound quality adjustment and
audibility characteristic correction control by digital arithmetic processing, that is, sound signal
processing of one system based on one control data.
[0015]
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Next, an example of a specific calculation method of control data to be output to the DSP 2
performed by the microcomputer 6 will be described. The microcomputer 6 first calculates the
frequency characteristic (hereinafter referred to as equalizer characteristic) to be applied to the
sound signal according to the operation state of the equalizer setting unit 8. That is, X1 Hz (X1
hertz) is calculated as Y1 dB (Y1 decibel) increase, X2 Hz as Y2 dB increase. Then, correction
(loudness correction) according to the operation state of the volume adjustment operation unit 9
is performed on this equalizer characteristic.
[0016]
FIGS. 2, 3 and 4 show different examples of the loudness correction, and these corrections can be
performed alone or in combination. Further, FIG. 5 shows an example of the correction amount
(with respect to the volume adjustment value) of the loudness correction shown in FIG. 2, FIG. 3
and FIG.
[0017]
The loudness correction shown in FIG. 2 increases / decreases the signal level of the bass and
trebleband in accordance with the operation state (volume adjustment value) of the volume
adjustment operation unit 9. In this example, the adB (bass range) in the equalizer characteristic
The signal level increased by 100 Hz) and b dB (high frequency range: 10 kHz) is further
increased by cdB and ddB according to the volume adjustment value. Then, as shown in FIG. 5,
the amount of increase increases as the volume adjustment becomes smaller (for example, there
is no increase (0 dB) at 0 to -10 dB, which is a large volume, and a small volume. 10 dB increase
in ˜)).
[0018]
The loudness correction shown in FIG. 3 increases / decreases the Q value (sharpness) of the
increase processing of the signal level in the low tone range and the high tone range according to
the operation state (volume adjustment value) of the volume adjustment operation unit 9. In the
example, the Q value is controlled in accordance with the volume adjustment value with respect
to the increase processing of the signal level in the low range (fL Hz) and the high range (fH Hz).
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Then, as shown in FIG. 5, the Q value becomes smaller as the volume adjustment becomes
smaller (the sharpness is smaller: the spread in the frequency axis direction is larger) (for
example, the volume is large) In the range of 0 to -10 dB, the Q value is 5 in both the low tone
range and the high tone range, and the Q value is 1 in the low tone range and the high tone
range when ˜ ∞ which is a small volume.
[0019]
The loudness correction shown in FIG. 4 increases or decreases the center frequency of the
process of increasing the signal level in the bass and trebleband regions according to the
operation state (volume adjustment value) of the volume adjustment operation unit 9. In this
example, the bass region The characteristic is that the center frequency (bass frequency fL0 Hz,
treble band fH0 Hz) is controlled in accordance with the volume adjustment value while the
signal level in the treble area is increased. Then, as shown in FIG. 5, the center frequency is set to
be higher on the low band side as the volume adjustment becomes smaller, and to be lower on
the high band side (for example, 0 which is a large volume). From -10 dB, the center frequency is
the low tone range fL1 and the high tone range fH1, and the low volume is ˜, the center
frequency is the low tone range fL5 and the high tone range fH5).
[0020]
In addition, when using some of the calculation methods of these equalizer characteristics in
combination, for example, the center frequency is fLHz, the Q value is 1 and the 10 dB signal
level is increased, and the high frequency range is fHHz, the Q value It is said that the signal level
is increased by 6 dB as 1. Further, the data shown in FIG. 5 is stored in the memory 5 and is used
at the time of equalizer characteristic calculation.
[0021]
FIG. 6 shows another example of loudness correction, which is not a so-called graphic equalizer
that can increase or decrease the signal level for many frequency points, but only the level
adjustment of the high range and the low range ( In addition to this, it is possible to apply to a
sound adjustment apparatus provided with a so-called BASS-TREBLE control, which can add a
middle range. FIG. 7 shows an example of the correction amount (with respect to the volume
adjustment value) of the loudness correction shown in FIG.
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[0022]
The loudness correction shown in FIG. 6 increases / decreases the turnover frequency of the
increase processing of the signal level in the low range and high range according to the operation
state (volume adjustment value) of the volume adjustment operation unit 9, and in this example
is low The characteristic is to control the turn-over frequency (bass frequency fL0 Hz, treble band
fH0 Hz) in accordance with the volume adjustment value while increasing processing of the
signal level in the tone range and high range is performed. Then, as shown in FIG. 7, the turnover
frequency is set to be higher on the low frequency side as the volume adjustment becomes
smaller, and to be lower on the high frequency side (for example, a large volume). At 0 to -10 dB,
the turnover frequency is the low tone range fL1 and the high tone range fH1, and the small
volume ˜ to the turnover frequency is the low tone range fL5 and the high tone range fH5). That
is, as the volume adjustment becomes smaller, the frequency band in which the increase
processing of the sound signal level in the BASS · TREBLE control is performed is expanded, and
eventually the loudness function is realized. The data shown in FIG. 7 is stored in the memory 5
and is used at the time of calculation of the BASS · TREBLE control characteristic.
[0023]
Although the sound adjustment apparatus according to the above-described embodiment has
been described in the configuration of one channel (monaural), it can be realized similarly by a
multi-channel sound adjustment apparatus such as stereo. In this case, 1 It is determined
whether to use a DSP for each channel or to share a DSP for several channels, and the sound
characteristic processing according to the volume setting value and the sound quality setting
value in one channel is performed by the same DSP Become.
[0024]
Brief description of the drawings
[0025]
1 is a block diagram showing a configuration of a sound adjustment device according to an
embodiment of the present invention.
[0026]
2 is a characteristic diagram showing an example of loudness correction by the signal level.
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[0027]
3 is a characteristic diagram showing an example of loudness correction by the Q value.
[0028]
4 is a characteristic diagram showing an example of the loudness correction by the center
frequency.
[0029]
5 is a table showing the loudness correction data stored in the memory.
[0030]
6 is a characteristic diagram showing an example of loudness correction by the turnover
frequency.
[0031]
7 is a table showing turnover frequency data stored in the memory.
[0032]
Explanation of sign
[0033]
DESCRIPTION OF SYMBOLS 1 ... Sound signal source 2 ... DSP3 ... Power amplifier 4 ... Control
part 5 ... Memory 6 ... Microcomputer (microcomputer) 7 ... Operation part
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