JP2010226413

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DESCRIPTION JP2010226413
An on-vehicle acoustic device and a vehicle-mounted acoustic device automatically adjust the
frequency characteristic of an audio output capable of suppressing the influence of chatter
without causing volume deterioration in a low frequency region more than necessary regardless
of the structure of a vehicle type A system and an acoustic control method are provided.
SOLUTION: An oscillator unit 110, which is one of a plurality of sound sources outputting a sine
wave with variable frequency, and a chattering component for extracting an audio signal level of
a predetermined frequency among audio signals collected and converted by a microphone 301.
An extraction unit 111, an audio filter unit 113 connected between a sound source and a speaker
and capable of variably setting the attenuation band, and a control unit 114 for setting the
attenuation band of the audio filter unit according to the extraction result of the chatter
component extraction unit. , And the control unit 114 compares the magnitude of the audio
signal extracted by the chatter component extraction unit 111 with a preset threshold, and when
the audio level is larger than the threshold, the sine wave being output at that time Is set as the
attenuation band of the voice filter unit 113. [Selected figure] Figure 2
In-vehicle acoustic device, in-vehicle acoustic system, acoustic control method
[0001]
The present invention relates to an on-vehicle acoustic device and an on-vehicle acoustic system
for automatically setting a frequency characteristic of an audio output to reduce an influence of a
parasitic vibration of an on-vehicle acoustic device and an interior product such as a door of a
vehicle equipped with the on-vehicle acoustic system. It relates to a control method.
[0002]
08-05-2019
1
In the case of using a commercially available in-vehicle acoustic device in which the vehicle type
of the vehicle equipped with the in-vehicle acoustic device is not specified or the in-vehicle
acoustic device mounted in a plurality of vehicle types, parasitic vibration (hereinafter referred to
as chatter) Since the input level to the speaker is detected by the level detection circuit, the level
detection circuit increases the cut-off frequency of the filter according to the preamplifier output.
It is known to prevent chattering by generating and inputting this to a filter (see, for example,
Patent Document 1).
Japanese Utility Model Application Publication No. 58-30320
[0003]
However, in the above-described conventional on-vehicle acoustic device, the cut-off frequency of
the low-pass filter for audio output is constant according to the output level. Therefore, as the car
body structure diversifies in recent years, the cut-off frequency is set at a frequency at which
chattering does not occur depending on the vehicle type of the vehicle equipped with the invehicle acoustic device, causing volume deterioration in the low frequency region more than
necessary There was a problem that there is a possibility.
[0004]
The present invention is an on-vehicle acoustic device that automatically adjusts the frequency
characteristic of a voice output that can suppress the influence of chatter without causing volume
deterioration in a low frequency region more than necessary regardless of the structure of a
vehicle type It aims at providing an acoustic system and an acoustic control method.
[0005]
The on-vehicle acoustic device according to the present invention is mounted on a vehicle, and
converts an audio signal output from a selected one of a plurality of sound sources provided in
the microphone and the own device, which collects sound in the room of the vehicle. An onvehicle acoustic device connected to a speaker for outputting voice, which is one of the plurality
of sound sources for outputting a sine wave with variable frequency, and an audio signal
collected and converted by the microphone A chattering component extraction unit for extracting
the magnitude of a speech signal of a predetermined frequency; a speech filter unit connected
between the sound source and the speaker and capable of variably setting the attenuation
08-05-2019
2
amount of the inputted speech signal; And a control unit for setting the attenuation amount of
the audio signal in the audio filter unit according to the extraction result of the component
extraction unit, wherein the control unit controls the size of the audio signal extracted by the
chatter component extraction unit. Ah The characteristics of the voice filter unit are set so as to
attenuate the voice signal of the frequency of the sine wave output at that time when the voice
level is larger than the threshold value by comparing with a preset threshold value.
Configuration.
[0006]
With this configuration, the audio signal level of the frequency that causes chattering in the
interior of the vehicle can be attenuated by the control of the on-vehicle acoustic device, so the
cutoff frequency may be set at a frequency that does not chatter In addition, regardless of the
structure of the vehicle type, it is possible to suppress the influence of chattering while
maintaining the sound quality to such an extent that the level of the minimum frequency range is
attenuated.
[0007]
Further, in the vehicle-mounted acoustic device according to the present invention, the
attenuation amount of the audio signal level set in the audio filter can be variably set, and the
control unit is the audio extracted by the chatter component extraction unit by the control unit.
The magnitude of the signal is compared with a preset threshold value, and the amount of
attenuation of the voice signal level set in the filter is set large until the voice level becomes
smaller than the threshold.
[0008]
According to this configuration, the level of the audio signal including the frequency component
causing the chatter is lowered more than necessary because the level of the audio signal
including the frequency component causing the chatter is attenuated while confirming
occurrence of the chatter in stages. Because it does not happen, it is possible to reliably suppress
the occurrence of chattering while maintaining high sound quality.
[0009]
The on-vehicle acoustic device according to the present invention further includes an operation
button unit connected to the control unit and transmitting an operation signal according to an
operation of the operator to the control unit, wherein the threshold value is the operation button
unit of the operator. The configuration is changed according to the operation of
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3
[0010]
With this configuration, the user who is the operator can change the threshold value that means
the presence or absence of chattering, so for example, even if chattering occurs a little, the voice
output of the frequency characteristic that is powerful or somewhat powerful It is possible to
listen to the audio output with the user's favorite frequency characteristic, such as setting the
audio output of the frequency characteristic with little influence of chattering even if there is no.
[0011]
Further, in the on-vehicle acoustic device of the present invention, the audio filter unit is
configured to attenuate an audio signal level of an audio signal having a frequency component
equal to or lower than the frequency of the audio signal for which the attenuation amount is set.
[0012]
According to this configuration, since the frequency components below the set predetermined
frequency are attenuated, it is possible to listen to the audio output of the frequency
characteristic that is totally comfortable.
[0013]
Further, in the on-vehicle acoustic device of the present invention, the audio filter unit is
configured to attenuate only the audio level having the frequency component of the audio signal
frequency for which the attenuation amount is set.
[0014]
According to this configuration, since the low frequency components of the audio signal are not
attenuated more than necessary, it is possible to listen to the audio output of the frequency
characteristic that is totally powerful.
[0015]
Further, the on-vehicle acoustic device of the present invention has a configuration in which the
operation unit includes a volume operation unit for adjusting the output volume, and the size of
the sound of the sine wave output by the oscillator is adjusted by the volume operation unit. ing.
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4
With this configuration, the control operation for suppressing chattering at the user's favorite
sound volume is performed, so that the influence of chattering is appropriately suppressed at the
sound volume of the preference that the user wants to hear even to the sound output from other
sound sources. It is possible to listen to the voice of the specified frequency characteristic.
[0016]
In the on-vehicle acoustic device of the present invention, the microphone is provided in the own
device.
[0017]
With this configuration, since the microphone and the in-vehicle acoustic device can be moved
together, it is easy to move the device.
[0018]
The sound control method according to the present invention is a sound control method for
listening to a sound output from one sound source selected from a plurality of sound sources
from a speaker mounted on a vehicle, which is a sound of a sine wave. The microphone outputs
the sound from the speaker toward the room of the vehicle, and the sound generated in the room
of the vehicle including the sound of the sine wave output from the speaker is collected by the
microphone provided in the room of the vehicle, and the microphone A voice signal of a
predetermined frequency is extracted from voice signals collected and converted, and the level of
the extracted voice is compared with a preset threshold, and the level of the extracted voice is
larger than the threshold In this case, an audio filter set to attenuate an audio signal having the
same frequency as the sine wave is controlled to be connected between the sound source and the
speaker.
[0019]
With this configuration, the sound signal level of the frequency that causes chattering in the
interior of the vehicle can be attenuated independently of the structure of the cabin of the
vehicle, so the cutoff frequency is set at a frequency at which chattering does not occur. It is
possible to suppress the influence of chattering while maintaining the sound quality to such an
extent that the level of the minimum frequency range is attenuated regardless of the structure of
the vehicle type.
[0020]
Furthermore, the on-vehicle acoustic system according to the present invention includes a
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5
microphone device mounted on a vehicle for collecting sound in the room of the vehicle, an
acoustic device having a sound source for outputting an audio signal, and an audio signal output
from the acoustic device. A speaker device for converting sound and outputting sound, an
oscillator device for outputting a sine wave with variable frequency, and a chatter for extracting
the size of a sound signal of a predetermined frequency among the sound signals collected and
converted by the microphone device. A component extraction device; an audio filter device
connected between the acoustic device and the speaker device, wherein the frequency of an
audio signal to be attenuated can be variably set; and the filter device according to the extraction
result of the chattering component extraction unit And a controller for controlling, the controller
comparing the magnitude of the audio signal extracted by the controller with the chatter
component extractor with a preset threshold value. Wherein when the audio level is greater than
the threshold value, and has a configuration of setting the audio filter to attenuate an audio
signal of a frequency of the sine wave being output at that time.
[0021]
With this configuration, the audio signal level of the frequency that causes chattering in the
vehicle cabin can be attenuated by the control of the in-vehicle acoustic system, so the cutoff
frequency may be set at a frequency that chattering does not occur. In addition, regardless of the
structure of the vehicle type, it is possible to suppress the influence of chattering while
maintaining the sound quality to such an extent that the level of the minimum frequency range is
attenuated.
[0022]
Moreover, the vehicle-mounted acoustic system of this invention has a structure where the
position in which the said microphone is provided is the center of the room interior of the said
vehicle.
[0023]
According to this configuration, the chattering component can be extracted on average from the
entire interior of the vehicle, so that the voice of the frequency characteristic in which the
influence of chattering is suppressed as in the case of being at any other position anywhere in
the vehicle interior You can listen to
[0024]
Further, in the on-vehicle acoustic system of the present invention, the on-vehicle acoustic
system includes a plurality of microphones, and the plurality of microphones are respectively
provided in seats provided in the interior of the vehicle.
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6
[0025]
With this configuration, it is possible to detect chattering using the voice signal of the sound
collected at the seat where the user listens to the voice, so that the frequency at which the
chatter suppression effect satisfying the user's request is obtained. You can listen to the voice of
the characteristic.
[0026]
The present invention provides an on-vehicle acoustic device that makes it possible to suppress
chattering of interior parts in a vehicle interior while reducing level deterioration in a low
frequency region as compared to the prior art, for any type of indoor structure vehicle. It is
something that can be done.
[0027]
According to the present invention, a sound of a sine wave is output from a speaker toward the
room of a vehicle, and a sound generated in the room of the vehicle including the sound of the
sine wave is collected by a microphone, and a predetermined sound is collected. It is judged from
the voice of the frequency whether chattering occurs or not, and if chattering occurs, sound
control is performed to suppress the influence.
[0028]
Here, the chattering refers to the sound generated by the vibration of the interior of the vehicle
interior due to the sound output from the speaker.
[0029]
Hereinafter, an on-vehicle acoustic device according to an embodiment of the present invention
will be described in detail with reference to the drawings.
[0030]
FIG. 1 is a diagram showing a schematic configuration of an on-vehicle acoustic system according
to an embodiment of the present invention.
08-05-2019
7
However, in FIG. 1, each device is schematically shown in order to easily show the arrangement
of each device constituting the on-vehicle acoustic system.
That is, FIG. 1 depicts a state where the vehicle is viewed from the outside of the ceiling surface
of the vehicle, and is also shown in such a way that the interior of the vehicle can be seen
through the ceiling surface, pillars and doors of the vehicle. There is.
[0031]
As shown in FIG. 1, an on-vehicle acoustic system 100 according to the present embodiment is
mounted on a vehicle 1 and a microphone 301 (301a to 301e is collectively referred to as 301)
as a microphone device that collects sound in the room of the vehicle 1 And a speaker 201 (201a
to 201d are collectively referred to as 201) as a speaker device that converts an audio signal,
which is an electrical signal, into a sound that is a physical vibration and outputs the voice
toward the room of the vehicle 1). An oscillator unit that outputs a sine wave with variable
frequency as described in detail, an oscillator unit that outputs a sine wave, a chattering
component extraction unit that is a chattering component extraction device that extracts a sound
of a predetermined frequency from the sound collected by the microphone 301, A sound source
device as a sound source device provided with a sound source such as a radio tuner, a disc player
or a memory card player, and a sound source device and a speaker The filter constant of the
audio filter unit is set to a desired value according to the extraction result of the audio filter unit
and the chatter component extraction unit, which are audio filter devices connected to and
reducing the audio level of a specific frequency by a desired size. It is comprised by the vehiclemounted acoustic device 101 in which the control part which is a control apparatus which
controls to perform is provided in the inside.
[0032]
The audio filter unit may be configured by an analog electric circuit using a capacitor, a resistor,
or the like, or a so-called digital filter realized by digital arithmetic processing may be used.
Therefore, the above-mentioned filter constant means the capacitance value of a capacitor, the
resistance value of a resistor, an operator used in digital arithmetic processing, and the like.
[0033]
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8
In the present embodiment, as shown in FIG. 1, the on-vehicle acoustic device 101 is located in
the front of the room of the vehicle 1 (in the forward direction of the vehicle) at a position where
the passenger (operator) at the front seat of the vehicle 1 can easily operate. It is arranged.
However, when it is possible to operate the in-vehicle acoustic device 101 using a wireless means
such as a remote control, the instrumental space under the seat or the vehicle 1 is taken into
consideration, taking into consideration the space of the vehicle interior (the interior of the
vehicle 1). The mounting location can be changed as appropriate, such as being buried inside the
panel.
[0034]
And although not shown in FIG. 1, the on-vehicle acoustic device 101 is electrically connected to
the speaker 201 which emits the voice signal outputted from the on-vehicle acoustic device 101
as voice to the passenger in the vehicle compartment. It is connected.
[0035]
In the present embodiment, the four speakers 201a to 201d fixed to the door of the vehicle 1 are
used as the speakers 201. However, the number of the speakers 201 may be one or more, and a
bass speaker such as a woofer is connected. It is good.
Further, the mounting position of the speaker 201 is not limited to the door, and may be installed
in a trunk room of the vehicle 1 or fixed to an instrumental panel.
[0036]
Further, the in-vehicle acoustic device 101 is disposed in the vehicle compartment, and is
electrically connected to a microphone 301 (301a to 301e collectively referred to as 301) for
collecting sound in the vehicle interior.
The shape of the microphone 301 does not matter.
08-05-2019
9
However, the microphone 301 uses a microphone having the ability to collect sound of at least
20 Hz to 20 kHz which is an audio frequency band.
[0037]
Here, only one microphone 301a may be disposed at a desired position in the vehicle
compartment in order to collect voices of the entire vehicle interior taking into consideration
space saving of the vehicle interior, or a car The microphones 301b to 301e may be disposed on
the respective headrests or the like on the respective seats in the vehicle compartment in
consideration of the voice listening positions of the respective seats seated on the respective
seats in the room.
[0038]
Alternatively, the microphone may be provided in the in-vehicle acoustic device 101. For
example, the microphone is fixed to the in-vehicle acoustic device 101 so as not to be affected by
vibration or the like, and the sound collecting portion of the microphone is disposed toward the
vehicle interior It may be done.
In the following description, in order to distinguish it from the microphone 301 provided in the
interior of the vehicle, the microphone in the case where the microphone is provided in the onvehicle acoustic device 101 is given the reference numeral 118 (ie,
As microphone 118 ".
[0039]
The connection between the in-vehicle acoustic device 101 and the speaker 201 and the
connection between the in-vehicle acoustic device 101 and the microphone 301 may be
connected by wireless means.
Further, as the microphones, only the microphone 118 may be connected, only the microphone
301 may be connected, or both the microphone 118 and the microphone 301 may be connected.
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[0040]
Next, the configuration of the on-vehicle acoustic device 101 will be described with reference to
FIG.
[0041]
FIG. 2 is a block diagram showing the main configuration of the on-vehicle acoustic device 101
according to the embodiment of the present invention.
[0042]
As described above, in the present embodiment, the on-vehicle acoustic device 101 includes the
oscillator unit 110 as the oscillator device, the chattering component extraction unit 111 as the
chatter component extraction device, the sound source 112 as the sound source device, and the
voice filter unit as the filter device. A control unit 114 as a control device is provided in the
inside.
Further, the on-vehicle acoustic device 101 is outputted from the operation button unit 115 for
the user, who is the operator, to operate each function of the on-vehicle acoustic device 101, the
mode selection unit 116 for selectively switching a plurality of sound sources, and the sound
source 112. An amplifier unit 117 which amplifies the audio signal at a predetermined
amplification factor is provided.
[0043]
The vehicle-mounted acoustic device 101 according to the present embodiment is provided with
two sound sources as a plurality of sound sources, one of which is a radio tuner 112a that
receives an AM radio or FM radio broadcast wave and outputs the received signal as an audio
signal The other is a media reproduction unit 112b that reproduces information recorded on a
recording medium such as an optical disc such as a CD (Compact Disc) or a DVD (Digital Versatile
Disc) or a memory card, and outputs the information as an audio signal.
Although only one media reproduction unit 112 b is described in FIG. 2, a plurality of media
reproduction units may be provided to reproduce a plurality of types of recording media.
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In the following description, the radio tuner 112a and the media reproduction unit 112b may be
collectively described as the sound source 112.
[0044]
The on-vehicle acoustic device 1 is provided with an oscillator unit 110 that outputs a sine wave,
which is an audio signal with a frequency of about 20 Hz to 300 Hz, in a variable manner, in
order to perform chatter detection described later.
[0045]
Here, to output a sine wave with variable frequency, the oscillator unit 110 has a function of
switching and outputting a sine wave of a frequency within a range of about 20 Hz to 300 Hz,
and the switching will be described in detail later. As a result, the frequency switching of the sine
wave output according to the signal output from the control unit 114 to the oscillator unit 110 is
performed.
This event is briefly expressed as "output sine wave with variable frequency".
[0046]
The output signal of each of the sound source 112 and the oscillator unit 110 is input to the
mode selection unit 116.
[0047]
However, although the sound source 112 and the oscillator unit 110 are separately expressed in
this embodiment for the sake of clarity in the description, the sound source 112 and the
oscillator unit 110 are provided in parallel in the circuit configuration as shown in FIG.
Therefore, the oscillator unit 110 can also be treated as one of the sound sources.
[0048]
The mode selection unit 116 selects one type of audio signal among the plurality of types of
audio signals input to the mode selection unit 116 and outputs the selected audio signal from the
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mode selection unit 116.
One type of audio signal output from the mode selection unit 116 is determined by the user
operating the operation button unit 115.
In this case, it is possible to use the portable music player as a sound source by making the onvehicle audio device 101 connectable to the portable music player and inputting the output
audio signal of the portable music player to the mode selection unit. It is.
[0049]
The audio signal selected by the user and output from the mode selection unit becomes a desired
audio signal by passing through the audio filter unit 113 described later, and this audio signal is
input to the amplifier unit 117 and the gain set in advance is set. And amplified into the vehicle
interior through the speaker 201.
[0050]
The operation button unit 115 outputs an operation signal according to the user's operation.
The output operation signal is input to the control unit 114 that performs overall control of the
in-vehicle acoustic device 1.
[0051]
The control unit 114 is realized by, for example, a microcomputer having a CPU, a ROM, and a
RAM, determines the operation signal input from the operation button unit 115, and detects any
audio signal of the radio tuner 112a, the media reproduction unit 112b, or the oscillator. Control
of outputting a signal from the mode selection unit 116 to the mode selection unit 116.
[0052]
Furthermore, the control unit 114 is also electrically connected to the audio filter unit 113
provided at the next stage of the mode selection unit 116.
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The audio filter unit 113 attenuates (decreases the level of) the audio signal level which is the
size of the audio signal only at a predetermined frequency or frequency domain of the added
audio signal, and the frequency to be attenuated can be variably set. It is a thing.
Here, to be able to variably set the frequency to be attenuated means that if the so-called digital
filter realized by digital operation (digital signal processing) is used for the audio filter unit 113,
the predetermined frequency to be attenuated is changed by changing the parameter used for
operation. It can be appropriately changed, or by providing a plurality of analog filters in a
switchable manner, it has a function capable of switching and setting the frequency to be
attenuated by the audio filter unit 113 to a value within a predetermined frequency range. In the
switching, the value of the frequency to be attenuated is switched according to the signal output
from the control unit 114 to the voice filter unit 113 as described later in detail.
This event is expressed simply as "the frequency to be attenuated can be set variably".
[0053]
The control unit 114 detects the level of the signal extracted by the chatter component extraction
unit 111, and performs control to set the frequency of the sine wave output from the oscillator
unit 110 according to the magnitude of the signal level. The unit 114 is also connected to the
chatter component extraction unit 111 and the oscillator unit 110.
[0054]
The chatter component extraction unit 111 passes only audio signals of frequencies within a
predetermined necessary range among audio signals collected by the microphone 301 or the
microphone 118, and does not pass (or attenuates) audio signals of other frequencies. A pass
filter or the like is provided in the input stage, and the audio signal passing through the input
stage is converted into an absolute value of the level of the audio signal using an integrating
circuit or the like.
In other words, the chatter component extraction unit 111 extracts an audio signal level of a
predetermined frequency from audio signals collected and converted by the microphone 301 or
the microphone 118.
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[0055]
However, the signal level after being converted into an absolute value by the chatter component
extraction unit 111 becomes large and exceeds the rated input level of the control unit 114 or
the limit of the ability of the control unit 114 to detect the signal level is exceeded. Since it may
happen that the absolute value information is level-shifted to an appropriate level by the level
conversion circuit in the output stage of the chatter component extraction unit 111, it is output
to the control unit 114.
[0056]
The operation button unit 115 outputs an operation signal according to the user's operation, and
the output operation signal is input to the control unit 114 that performs overall control of the
on-vehicle acoustic device 101.
That is, in order to adjust the mode selection button for selecting the sound source from which
one of the radio tuner 112a which is the sound source 112 and the media reproduction unit
112b to be output to the operation button portion 115, the general preset button and the
volume. Also included are volume controls such as rotary volume and encoder volume.
However, the volume operation unit is not limited to the rotary type, and a unit that raises and
lowers the sound volume with a push-type button or switch may be used.
[0057]
Further, the operation button unit 115 is provided with a chatter detection mode button for
selecting the operation of the in-vehicle acoustic device 101 to shift to the chatter detection
mode as described later in detail.
[0058]
The operation button unit 115 may be fixed to the in-vehicle acoustic device 101. However, the
operation button unit 115 may be connected by wire or may be operated wirelessly like a remote
controller.
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[0059]
As described above, the on-vehicle acoustic device 101 according to the present embodiment
collects the sound in the vehicle and can connect to the on-vehicle acoustic device 101 or the
microphone 118 provided in the on-vehicle acoustic device 101, and the microphone 301 or the
microphone A chattering component extraction unit 111 that extracts the frequency component
generated by chattering of the interior of the vehicle compartment from the frequency
component of the sound collected from 118, and the presence or absence of chattering of the
interior of the cabin according to the extracted component A control unit 114 which makes a
determination, selects a predetermined audio filter from the audio filter unit 113 in which plural
types of audio filters are prepared according to the presence / absence detection, and controls
mode selection by a button operation of the user; The oscillator unit 110 that can output a sine
wave that is variable with both gain and gain, and the voice that has passed through the voice
filter unit 113 is amplified. A structure having an amplifier portion 117.
[0060]
Then, in the in-vehicle acoustic system 100 of the present embodiment, the sine wave of the
frequency f output from the oscillator unit 110 is amplified by the amplifier unit 117, is output
from the speaker 201, and is reflected by the interior of the vehicle interior such as a door or
seat. The collected sound is collected by the microphone 301 or the microphone 118, and the
frequency component of the collected sound is analyzed.
At this time, there is no chattering when only the component of the frequency f output from the
speaker 201 is detected, and when a frequency component other than the frequency f is
detected, the sound is generated due to the vibration of the interior of the vehicle interior.
Therefore, I judge that there is chattering.
When it is determined that a chatter is present, sound control is performed to reduce the
influence of the chatter.
[0061]
The operation of the in-vehicle acoustic system configured as described above will be described
with reference to FIG.
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However, in the following description, in order to simplify the description, control when one
microphone is used will be described, and it is assumed that the microphone uses the
microphone 118 provided in the on-vehicle acoustic device 101.
[0062]
FIG. 3 shows a flow chart of the operation in the chatter detection mode of the on-vehicle
acoustic system according to the embodiment of the present invention.
[0063]
The transition to the chatter detection mode is performed by the user operating the chatter
detection mode button of the operation button unit 115.
[0064]
When the chattering detection mode is selected, a low frequency sine wave signal having a
volume set so that the volume of the sound output from the speaker 201 becomes the volume of
the user's preference first passes from the oscillator unit 110 through the voice filter unit 113.
Then, the signal is output to the amplifier unit 117, the signal is amplified by the amplifier unit
117, and the speaker outputs the sound into the car (step S101).
[0065]
Here, in the present embodiment, the frequency of the sine wave output first is the lowest
frequency 20 Hz sine wave that can be output by the oscillator unit 110.
Also, as described later, there is a case where a sine wave of the same frequency is output to
perform chatter detection, and then a sine wave of a different frequency is output to perform
chatter detection, but the first to be performed at the same frequency At the time of the
operation of chattering detection, it is assumed that the sound filter portion 113 does not
attenuate the sine wave signal outputted from the oscillator portion 110.
[0066]
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Next, the sound output from the speaker 201 in step S101 is collected by the microphone 118
together with the sound reflected by the interior of the vehicle interior (step S102).
When the frequency component other than the sine wave signal (hereinafter referred to as
desired wave) output from the oscillator unit 110 is extracted by the chatter component
extraction unit 111 and the control unit 114 sees the interior parts in the vehicle interior
Whether or not there is a chatter is detected depending on whether or not frequency
components other than the desired wave generated in are extracted.
[0067]
That is, only an audio signal of a predetermined range of frequency is allowed to pass through
the audio signal collected from the microphone 118 by the band pass filter provided inside the
chatter component extraction unit 111 (step S103). The voice level is converted into an absolute
value using an integration circuit inside the chattering component extraction unit 111 provided
at a stage subsequent to the above-mentioned band pass filter (step S104).
The information of the absolute value is converted or processed into an appropriate signal so
that the control unit 114 can recognize it, and then transmitted to the control unit 114 to
convert the information into a threshold and an absolute value preset in the control unit 114.
The presence or absence of chattering is determined by comparing with the calculated value
(step S105), that is, the control unit 114 detects whether the specific voice component extracted
by the chatter component extracting unit 111 is present at a certain level or more. Therefore, the
presence or absence of chattering is determined.
[0068]
Then, as a result of the determination in step S105, when the control unit 114 determines that
"no chattering" (step S106), it is determined whether the frequency of the desired wave output
from the oscillator unit 110 is less than 300 Hz ( Step S116) If not less than 300 Hz, the
operation of the chatter detection mode is ended.
The output of the oscillator unit 110 is stopped simultaneously with the end of the chatter
detection mode.
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Further, when the operation of the chatter detection mode is finished, the end of the chatter
detection mode may be displayed to the user by a message or the like, or an alert sound may be
emitted.
[0069]
When it is determined in step S105 that the chatter is present and the control unit 114
determines that the chatter is present (step S107), the volume level of the frequency of the
desired wave used to determine the chatter presence or absence at this time is determined. A
filter to be attenuated is selected from the voice filter unit 113 by an instruction signal from the
control unit 114.
In this case, filter selection is processed in the following flow.
[0070]
When it is determined in step S107 that "the chatter is present", the control unit 114 checks the
frequency of the signal (desired wave) output from the oscillator unit 110 at that time (step
S108).
[0071]
At this time, the control unit 114 has a counter indicating how many times the vibration
detection operation of the frequency of the desired wave output from the oscillator unit 110 is
performed, and confirms the counter number n after step S108 (step S109).
[0072]
Then, based on the number n of counters checked in step S109, it is checked whether an n-order
filter exists (step S110).
Here, the n-th-order filter is stepped so that the level decrease (attenuation amount) below the
frequency f of the desired wave output from the oscillator unit 110 is increased so that the
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frequency characteristic shown in FIG. 4 is obtained. The level reduction amount is set to 1, the
first order filter, the second order filter, the third order filter ... the order of the level reduction
from the filter with the small level reduction of the low frequency region below the frequency f in
the order of the nth order filter It is preset to be able to sequentially select large filters.
[0073]
That is, the attenuation amount of the audio signal level set in the audio filter unit 113 can be
variably set by the control signal of the control unit 114, and the first detection of chattering in
the chattering detection operation using the desired wave of the same frequency. After it is
determined that "the chatter is present", the primary filter with the smallest level decrease is
selected among the plurality of n-order filters, and after the chattering detection is determined to
be "the chatter is present" for the second time and thereafter, 2 Next filter, third order filter... N
order filter is selected.
[0074]
Note that the amount of attenuation of the audio signal level can be set variably means that the
signal level of the predetermined frequency to be attenuated if the so-called digital filter realized
by digital operation (digital signal processing) is used for the audio filter unit 113. The amount of
attenuation of the audio signal, which indicates how much the signal is attenuated, can be
appropriately changed by changing the parameters used for the calculation, and in the case of a
configuration in which a plurality of analog filters are switchably provided, the audio filter unit
113 A plurality of filters having different attenuations are provided and can be set to switch and
use them. The switching is performed by switching the value of the attenuation according to the
signal output from the control unit 114 to the audio filter unit 113. It will be
This event is briefly expressed as "the attenuation of the audio signal level can be set variably".
[0075]
If it is confirmed in step S110 that the n-order filter exists, the n-order filter is selected (step
S111), and the desired wave output from the oscillator unit 110 at that time passes through the
voice filter unit 113. The selected n-order filter is mixed (step S112), and the audio signal is
amplified again by the amplifier unit 117 (step S113), and the speaker 201 outputs the sound
(step S114).
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The audio signal output from the speaker 201 in step S114 is echoed by the interior of the
vehicle interior, collected again by the microphone 118, and chattering detection is performed
again.
[0076]
In step S110, if it is not confirmed that the n-th filter exists or if it is confirmed that the n-th filter
does not exist, the control unit 114 outputs an instruction signal to the oscillator unit 110 and
outputs it from the oscillator unit 110. It is controlled to raise the frequency (sine wave) of the
desired wave to be generated (step S115).
In the present embodiment, the increase width of the frequency at this time is in 1 Hz steps, but
the increase width of the frequency may be a parameter that can be changed as appropriate.
[0077]
Then, in the state where the frequency of the desired wave is increased in step S115, the
chattering detection operation after S101 is executed, and the flow after step S101 is repeated
until the end.
[0078]
When the operation flow of the chattering detection mode is processed to end , the user
operates the mode selection button of the operation button unit 115 to output the other audio
equipment 101 such as the audio output from the radio tuner 112 b or the media reproduction
unit 112 a. It is possible to select an audio listening mode output from a sound source.
In this case, when the chattering detection mode operation is finished and the other mode is to
be listened to, the filter set in the audio filter unit 113 is a filter that lowers the level of a specific
frequency that generates chattering, so from other sound sources Even when the audio signal
being output is output from the speaker 201, chattering does not occur.
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[0079]
As described above, according to the on-vehicle acoustic system of the present embodiment, the
voice filter for suppressing the occurrence of chattering or preventing chattering is selected
based on the frequency of the desired wave output from the oscillator unit 110. Therefore, since
it is possible to specify and attenuate the frequency that needs to be attenuated, it is necessary
compared to the one using a sound filter having a constant cutoff frequency regardless of the
frequency of the sound output from the conventional speaker 201 It is possible to prevent the
voice band level from being reduced above.
[0080]
In the present embodiment, when the user selects the chattering detection mode at operation
button section 115, oscillator section 110 outputs a sine wave signal of 20 Hz to 300 Hz with a
user-selected volume value. .
As a result, the larger the volume value of the audio output, the higher the possibility of
chattering, and the smaller the smaller, the harder the chattering occurs. Therefore, by
performing chattering detection with the user-selected volume value, it is possible to use a fixed
voice filter. As compared with use, an appropriate voice filter can be selected according to the
output level of voice, and the user's needs can be more reliably met.
[0081]
In addition, since the chattering phenomenon in the vehicle compartment generally occurs due to
the resonance between the sound output in the low frequency region and the interior such as the
door of the vehicle compartment or the vibration due to the sound pressure, the voice of the
oscillator unit 110 is used in this embodiment. The output frequency band is 20 Hz to 300 Hz,
which is the lower limit of the human audible band.
[0082]
Then, a threshold set in advance in the control unit 114 is recorded as a data table in the ROM or
the like of the control unit 114, and the control unit 114 detects the signal level in the passenger
compartment in the non-output state. The corresponding threshold value is read out from the
data table and compared with the output signal level from the chatter component extraction unit
111.
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[0083]
Furthermore, it is also possible to increase or decrease the threshold value by adding or
subtracting a predetermined value to the threshold value set in advance.
In this case, an operation function for increasing or decreasing the threshold value is set in the
operation button unit 115, and the threshold value can be increased or decreased according to
the operation of the operator, that is, the user's operation as the operator. By doing this, it is
possible to hear bass (low-range voice), such as in a state where no chattering occurs in the cabin
at all, such as a state in which the auditory feeling of low-range voice is not impaired even if
slight chatter occurs in the cabin. There is an advantage that it is possible to select the balance
between the force and the suppression of chatter in the vehicle compartment according to the
preference of the user.
[0084]
Next, FIG. 6 shows an example of actual vehicle measurement data when the chatter detection
mode is executed using the on-vehicle acoustic system according to the embodiment of the
present invention in the room of the same vehicle.
The data shown in FIG. 6 is obtained by frequency analysis of the sound collected by a
microphone 301 provided in the cabin of a general vehicle, and the horizontal axis represents the
frequency in logarithm and the vertical axis represents the level of the audio signal. It was taken.
[0085]
In FIG. 6A, the frequency component analysis in a state where chattering is occurring without the
filter effect in the voice filter unit 113 is 601, and the frequency component analysis when no
chattering occurs is 602, a chattering occurs. The frequency of the output (desired wave) from
the oscillator unit 110 in the current state is 603, the level of the sound output of the desired
wave is 604, and the desired wave passes through the filter of the sound filter unit 113. The
sound output level of the wave is indicated by 605, and the output 606 of the frequency band
other than the desired wave which is a component of chattering sound, and in FIG. 6A, the
frequency of the desired wave is 63 Hz.
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[0086]
Similarly, in FIG. 6B, the frequency component analysis in a state where chattering is occurring
without the filter effect in the voice filter unit 113 is 608, the frequency component analysis
when the chattering is not occurring is 609, the chattering occurs A state where the frequency of
the output (desired wave) from the oscillator unit 110 in the state where it is being operated is
610, the level of the sound output of the desired wave is 611, and the desired wave passes the
filter of the sound filter unit 113 to suppress chattering. The voice output level of the desired
wave in is indicated by 612 and the output 613 of the frequency band other than the desired
wave which is the component of chattering sound, and in FIG. 6B, the frequency of the desired
wave is 100 Hz.
[0087]
As can be seen from FIG. 6A, with regard to the sound level in the frequency range indicated by
606, the difference between the sound level between the filter 601 and the filter 602 reduces the
level of the desired wave by the effect of the filter. .
That is, a voice having a frequency component within the frequency range indicated by 606
appears chattering.
[0088]
Similarly, as can be seen from FIG. 6 (b), with regard to the sound level in the frequency range
shown in 613, the sound level of 609 with no filter effect and 609 with the desired wave level
reduced by the filter effect. Deviation is large.
That is, a voice having a component of a frequency within the frequency range indicated by 613
appears chattering.
[0089]
That is, as can be seen from FIGS. 6 (a) and 6 (b), in a general vehicle, the frequency component
of the chattering noise is a frequency band other than the desired wave and is concentrated in
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the frequency band of 500 Hz or more. I understand.
And the frequency band of this chattering sound includes 500 Hz to 8 kHz which is the most
sensitive frequency band with respect to the frequency characteristic of the human ear.
[0090]
Therefore, in step S103 in the above-described operation flow of chattering detection, the sound
collected from the microphone 118 is subjected to a band pass filter of 500 Hz to 8 kHz, which is
the most sensitive frequency band in the characteristics for the frequency of the human ear. It is
understood that it is effective to convert the voice level into an absolute value by the integration
circuit, set the threshold of chattering detection by the control unit 114, and determine the
presence or absence of chattering.
[0091]
As described above, the filter characteristic of the audio filter unit 113 after the attenuation band
is set in the present embodiment is set to lower the signal level in the entire low frequency region
lower than the frequency f as shown in FIG. However, as shown in FIG. 5, this filter characteristic
may attenuate only a signal of a predetermined frequency f.
When the characteristic shown in FIG. 4 is adopted, since frequency components below a set
predetermined frequency are attenuated, when an audio signal such as music passes through this
filter, an audio with frequency characteristics that does not make the user feel uncomfortable as
a whole. The output can be heard, and when the characteristics shown in FIG. 5 are adopted,
although there may be some cases where the sense of incongruity may occur, the low frequency
component of the audio signal is not attenuated more than necessary. The audio output of the
frequency characteristic can be listened to.
[0092]
And although the case where the microphone 118 provided in the vehicle-mounted acoustic
device 101 was used was demonstrated in the above description, in this case, since the
microphone 118 is provided in the vehicle-mounted acoustic device 101, the microphone 118
and the vehicle-mounted Since the sound device 101 can be transferred together, the transfer of
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the device becomes easy.
Therefore, even if the microphone is not disposed in advance in the vehicle, the user (or an
installer of the in-vehicle acoustic device) can be easily installed in many vehicle types, and the
above-described effects can be easily obtained.
[0093]
However, if a desired position is provided only at the approximate center of the vehicle
compartment, as in the position of the microphone 301a shown in FIG. 1, the chattering
component can be extracted on average from the entire vehicle interior, so the vehicle interior
Wherever you are, you can listen to the voice of the frequency characteristic where the influence
of chatter is suppressed as well as when you are at other positions.
[0094]
Alternatively, although the signal processing is somewhat complicated as compared with the case
where a single microphone is used, if each is provided in a seat provided in the vehicle
compartment as in 301 b to 301 c in FIG. Since it is possible to detect chatter in a detailed
manner, it is possible to listen to the voice of the frequency characteristic where the chatter
suppression effect meeting the user's request is obtained.
[0095]
Then, in the present embodiment, the chatter extraction unit is a simple BPF but a voice signal
collected by the microphone 301 is analyzed using a measuring device such as an FFT (Fast
Fourier Transform) analyzer, If the analysis result is displayed on the display, the user can
visually recognize the occurrence of chattering, and the user can easily set the threshold value,
and the operability of the in-vehicle acoustic system 100 is improved. improves.
[0096]
As described above, according to the present invention, when the level of the audio signal
extracted by comparing the level of the audio signal extracted by the chatter component
extraction unit with the threshold set in advance is larger than the threshold, the output is made
at that time Since the frequency of the sine wave being set is set as the frequency to be
attenuated by the voice filter unit, the voice signal level of the frequency causing the chattering
in the vehicle room can be attenuated in a variable manner. The cutoff frequency is never set at a
frequency that does not occur, and the influence of chattering is suppressed while maintaining
the sound quality such that the level of the minimum frequency range is attenuated regardless of
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the structure of the vehicle type be able to.
[0097]
Further, according to the present invention, since the attenuation amount of the audio signal to
be attenuated by the audio filter can be set variably, the level of the audio signal including the
frequency component causing the chattering while checking the occurrence of chattering in
stages. Therefore, since the level of the audio signal is not lowered more than necessary, it is
possible to reliably suppress the occurrence of chattering while maintaining high sound quality.
[0098]
Also, generally speaking, chattering is often caused by the influence of bass, and it is often
necessary to lower the bass level in order to suppress the influence of chattering, and raising the
bass level causes ill effects of chattering. However, according to the present invention, the user
can change the threshold value, which is a value for determining the presence or absence of
chattering by operating the operation button section, so that the user balances chattering with
bass. It can be adjusted and can listen to the audio output with the user's favorite frequency
characteristics.
[0099]
Further, according to the present invention, since the audio filter section attenuates the audio
level having a frequency component lower than the set frequency, it is possible to listen to the
audio output of the frequency characteristic that does not make the user feel uncomfortable
overall.
[0100]
Further, according to the present invention, since the voice filter unit attenuates only the voice
level having a specific frequency component, the low frequency component of the voice signal is
not attenuated more than necessary, and the powerful frequency characteristic is obtained. You
can listen to the audio output.
[0101]
Further, according to the present invention, since the magnitude of the sound of the sine wave
output by the oscillator can be adjusted by the volume operation unit, the frequency at which the
influence of chattering is appropriately suppressed at the desired volume level that the user
wants to listen to You can listen to the voice of the characteristic.
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[0102]
As described above, the on-vehicle acoustic device, the on-vehicle acoustic system, and the
acoustic control method according to the present invention can reduce the level deterioration in
the low frequency region as compared to the prior art for any type of indoor structure vehicle.
The present invention has the effect of being able to provide an on-vehicle acoustic device
capable of suppressing chatter of the interior components of the vehicle, and an interior
component such as a door of a vehicle on which the acoustic device is mounted in the on-vehicle
acoustic device The present invention is useful as an on-vehicle acoustic apparatus, an on-vehicle
acoustic system, an acoustic control method, and the like for automatically setting the frequency
characteristic of audio output in order to reduce the influence of the parasitic vibration.
[0103]
Configuration diagram of on-vehicle acoustic system according to an embodiment of the present
invention Configuration diagram of on-vehicle acoustic apparatus according to an embodiment of
the present invention Flow chart of a method for extracting and judging chattering components
according to an embodiment of the present invention Voice according to an embodiment of the
present invention Characteristic diagram of the filter unit Characteristic diagram of another voice
filter unit according to the embodiment of the present invention (a) Diagram showing
measurement data of an actual vehicle equipped with the on-vehicle acoustic system according to
the embodiment of the present invention (b) Embodiment of the present invention Shows
measurement data of a real vehicle equipped with an on-board acoustic system in the form of
[0104]
DESCRIPTION OF SYMBOLS 1 vehicle 100 vehicle-mounted acoustic system 101 vehiclemounted acoustic device 110 oscillator part 111 chatter component extraction part 112 sound
source 113 audio ¦ voice filter part 114 control part 115 operation button part 116 mode
selection part 117 amplifier part 118 microphone 201 speaker 301 microphone
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