JP2007189515

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DESCRIPTION JP2007189515
To reproduce sound simultaneously with a plurality of types of speakers having different sound
generation efficiency, to set the volume of the low-efficiency speaker to a more appropriate state
while suppressing a defect such as a sound break. An audio signal adjustment device for
adjusting an audio signal to be supplied to at least one low efficiency speaker and one high
efficiency speaker, which are speakers different in sound generation efficiency, and is supplied to
the low efficiency speaker The first adjustment means for adjusting the volume of the audio
signal, the second adjustment means for adjusting the volume of the audio signal supplied to the
high efficiency speaker, and the predetermined range of the instructed volume level for the low
efficiency speaker and the high efficiency speaker, According to the command volume level, the
first sound pressure level, which is the sound pressure level of the audio signal supplied to the
low efficiency speaker adjusted by the first adjustment means, is adjusted by the second
adjustment means to the high efficiency speaker And sound pressure level control means for
setting the sound pressure level of the supplied audio signal to be equal to or higher than a
second sound pressure level. [Selected figure] Figure 4
Audio signal conditioner, audio system, car audio system
[0001]
The present invention relates to an audio signal adjustment device that adjusts audio signals
supplied to speakers having different sound generation efficiencies, for example, low efficiency
speakers and high efficiency speakers, and particularly performs adjustment regarding volume.
[0002]
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1
For example, in an audio system mounted on a vehicle, when a sound field or a sound image is
formed by speakers installed at left and right door portions of the vehicle, the installation
position or the like does not make the system suitable for the user (passenger of the vehicle).
There is.
Therefore, in order to make the sound field and the sound image formed in the vehicle more
appropriate, in addition to the speakers of the left and right door parts, there is disclosed a
technology of providing flat panel speakers in front of or behind the vehicle ceiling ( See, for
example, Patent Documents 1 and 2.).
[0003]
In these technologies, the user of the vehicle interior raises the sound field formed in the vehicle
interior by providing a flat panel with a wide directivity on the vehicle ceiling to correct the
acoustic characteristics by the door speaker. It becomes possible to form a suitable sound field
and sound image. In addition, since the flat panel speaker has a wide directivity, the synthesized
sound by the flat panel speaker and the speakers at the left and right door parts is formed in a
state having a circular spread with the user at the center, and the sound spread is excellent. ing.
[0004]
In addition, a technology relating to a vibration transducer as a vibration generating device for
configuring a flat panel speaker is disclosed (for example, see Patent Document 3). In this
vibration transducer, the fluctuation of the magnetic flux generated between the coil and the
magnet assembly is used to vibrate a member to be vibrated, for example, an interior material in
a car such as a ceiling panel to function as a speaker. Patent Document 1: Japanese Patent
Application Laid-Open No. 2004-168267 Patent Document 2: Japanese Patent Application LaidOpen No. 2004-168265 Patent Application Publication No. 11-512252
[0005]
For example, in the case where voices are simultaneously reproduced by a plurality of types of
speakers having different voice generation efficiencies, as in the above flat panel speakers and
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door speakers, when the drive signal levels to the respective speakers are the same, the low
efficiency speakers The volume is low and the audio is hard to hear. However, if the drive signal
level of the low efficiency speaker is set to be higher than that of the high efficiency speaker, the
low efficiency speaker may be saturated first when the volume is increased, which may cause a
problem such as a sound break. In particular, in a speaker using the above-mentioned vibration
transducer, since a ceiling panel or the like which does not necessarily have good characteristics
may be used as a diaphragm, the sound generation efficiency is lower than that of a general cone
type speaker, There is a possibility that the failure mentioned in the above low efficiency speaker
may occur.
[0006]
In the present invention, in view of the above-mentioned problems, when simultaneously
reproducing sound with a plurality of types of speakers having different sound generation
efficiency, the sound volume at the low efficiency speaker is more appropriate while suppressing
defects such as sound cracking. The purpose is to
[0007]
In the present invention, in order to solve the above-mentioned problems, the adjustment of the
sound pressure level in the low efficiency speaker and the adjustment of the sound pressure level
in the high efficiency speaker are made different according to the command volume level to each
speaker. .
By doing so, it becomes possible to make the volume of the low-efficiency speaker more
appropriate while suppressing problems such as sound cracking when reproducing sound.
[0008]
In particular, the present invention is an audio signal adjusting device for adjusting an audio
signal to be supplied to at least one low efficiency speaker and one high efficiency speaker,
which are speakers different in sound generation efficiency, The first adjustment means for
adjusting the volume of the audio signal supplied to the efficiency speaker, the second
adjustment means for adjusting the volume of the audio signal supplied to the high efficiency
speaker, the low efficiency speaker and the high efficiency speaker In a predetermined range of a
command sound volume level, according to the command sound volume level, a first sound
pressure level, which is a sound pressure level of a sound signal supplied to the low efficiency
speaker, adjusted by the first adjusting means, And sound pressure level control means for
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setting the sound pressure level of the audio signal supplied to the high efficiency speaker
adjusted by the adjustment means to a second sound pressure level or higher.
[0009]
In the audio signal adjustment device according to the present invention, the same audio signal is
supplied to at least two types of low-efficiency speakers and high-efficiency speakers having
different audio generation efficiencies, and audio is reproduced.
The difference in the generation efficiency is due to all factors such as the structure and shape of
the speaker. Then, the volume of the audio signal supplied to the low efficiency speaker and the
high efficiency speaker is controlled by adjusting the sound pressure level of the audio signal
supplied to each by the first adjustment means and the second adjustment means. Ru.
[0010]
Here, in the audio signal adjustment device according to the present invention, the first sound
pressure level which is the sound pressure level of the audio signal supplied to the low efficiency
speaker adjusted by the first adjustment means by the sound pressure level control means; (2) A
predetermined range of the command volume level for each speaker so that the relative
relationship with the second sound pressure level which is the sound pressure level of the sound
signal supplied to the high efficiency speaker adjusted by the adjustment means becomes higher
than the latter. Is controlled according to the command volume level. Here, with the command
volume level, an output is commanded to each speaker in response to a request from a user
(hereinafter simply referred to as a "user") who listens to the voice from the low efficiency
speaker and the high efficiency speaker. Say the volume level. And the predetermined range is
the range of the command sound volume level at which problems such as sound splits do not
occur because the first sound pressure level of the low efficiency speaker is further increased by
the sound pressure level adjusting means, in other words, the use of the user The range of
command volume level that does not cause trouble in the range.
[0011]
As described above, by causing the first sound pressure level and the second sound pressure
level to be in a predetermined relative relationship by the sound pressure level control means, a
problem such as a sound break occurs when the volume increases. It becomes possible to make it
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easy for the user to hear the sound from the low-efficiency speaker.
[0012]
Here, with regard to the adjustment of the audio signal by the sound pressure level control
means, more specifically, in the range of the low sound volume level within the predetermined
range of the command sound volume level, the first sound pressure level with respect to the
command sound volume level Adjusting the sound pressure level of the audio signal supplied to
the low efficiency speaker and / or the high efficiency speaker such that the ratio of the second
sound pressure level to the command sound volume level is higher, and the command sound
volume The ratio of the first sound pressure level to the instructed sound volume level is
substantially the same as the ratio of the second sound pressure level to the instructed sound
volume level in a range on the medium sound volume level side of the predetermined range of
levels. The sound pressure level of the audio signal supplied to the low efficiency speaker and /
or the high efficiency speaker may be adjusted.
[0013]
In the low volume level range of the specified range of the command volume level, even if the
first sound pressure level is set relatively high with respect to the second sound pressure level,
there is room for sound generation by the low efficiency speaker, and the sound is Cracks are
unlikely to occur.
Therefore, in such a case, the first sound pressure level may be set as large as possible in
accordance with the use situation of the user.
However, if the command volume level rises and becomes a volume level higher than the middle
volume level, that is, the above-mentioned low volume level, the probability of occurrence of a
problem with the low efficiency speaker increases, and in such a case, The rate of increase of the
first sound pressure level (ratio of the first sound pressure level to the above command volume
level) is similar to the rate of increase of the second sound pressure level (ratio of the second
sound pressure level to the above command volume level) I assume. In this way, it is possible to
keep the volume of the low efficiency speaker larger while suppressing the problem with the low
efficiency speaker.
[0014]
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The first sound pressure level and the second sound pressure level are the same in the range of
the high sound volume level side of the predetermined range of the command sound volume
level, in consideration of an increase in the probability of occurrence of a problem with the low
efficiency speaker. It may be
[0015]
Further, with regard to another adjustment of the audio signal by the sound pressure level
control means, more specifically, in the range of the low sound volume level within the
predetermined range of the command sound volume level, the first sound pressure to the
command sound volume level The ratio of the level is higher than the ratio of the second sound
pressure level to the command sound volume level, and the ratio of the first sound pressure level
to the command sound volume level takes a maximum value in any of the ranges, and the
command As the sound volume level increases, the ratio of the first sound pressure level to the
command sound volume level gradually decreases, and further, the first sound pressure level is
increased in the high sound volume side of the predetermined range of the command sound
volume level. The second sound pressure level may be equal to the second sound pressure level.
[0016]
In this adjustment by the sound pressure level control means, the ratio of the first sound
pressure level to the command sound volume level decreases with the increase of the command
sound volume, and the first sound pressure level and the second sound pressure level finally
coincide Control is performed by the sound pressure level control means.
That is, by the control, the magnitude of the first sound pressure level to the second sound
pressure level is gradually decreased as the command sound volume level is increased.
In this way, it is possible to keep the volume of the low efficiency speaker larger while
suppressing the problem with the low efficiency speaker.
[0017]
Here, in the sound signal adjusting device described above, the sound pressure level control
means may change the sound pressure of the sound signal supplied to each of the low efficiency
speaker and the high efficiency speaker according to the frequency of the sound signal supplied
thereto. Frequency characteristic adjusting means for adjusting the level is provided, wherein the
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frequency characteristic adjusting means sets the first sound pressure level above the second
sound pressure level in a predetermined frequency range of the supplied audio signal to each.
You may
[0018]
That is, also from the viewpoint of adjustment of the sound pressure level for each frequency of
the audio signal by the frequency characteristic adjusting means such as the equalizer, the sound
pressure level control means performs the second sound pressure level adjustment via the
frequency characteristic adjusting means. By setting the sound pressure level or higher, it is
possible to make the sound from the low efficiency speaker more audible to the user.
The above-mentioned predetermined frequency range is a frequency range of the audio signal for
making it easy to hear the sound from the low efficiency speaker efficiently, and may be set as
appropriate. Further, the frequency characteristic adjusting means does not prevent the first
sound pressure level from being equal to or higher than the second sound pressure level over the
entire frequency range in the user's audible range.
[0019]
Here, in the sound signal adjusting device described above, the sound pressure level control
means sets the first sound pressure level during a predetermined time when a predetermined
condition is satisfied, the first sound pressure level being a normal time other than the
predetermined time. It may be made higher than the one sound pressure level.
[0020]
The predetermined condition is a condition serving as a trigger for causing the user to recognize
the reproduction when the sound is reproduced by the low efficiency speaker, for example, when
the reproduction of the sound is started by the low efficiency speaker, the low efficiency When
the source of the sound reproduced from the speaker is changed.
In such a case, by setting the first sound pressure level higher than the normal first sound
pressure level, it is possible to direct the user's awareness to the low efficiency speaker. As a
result, it is possible to efficiently listen to the user the sound reproduced from the low efficiency
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speaker. The predetermined time may be any time sufficient to direct the user's awareness to the
low-efficiency speaker, and can be appropriately verified and set by experiments or the like.
[0021]
Further, in the sound signal adjusting device described above, the sound pressure level control
means sets the first sound pressure level to the second sound pressure level or more during a
predetermined time when a predetermined condition is satisfied. You may
[0022]
The predetermined conditions and the predetermined time are the same as those described
above.
That is, by setting the timing at which the first sound pressure level and the second sound
pressure level are adjusted by the sound pressure level control means to be during this
predetermined time, it is possible to make the user's awareness turn to the low efficiency speaker
Become. Therefore, after the elapse of the predetermined time, even if the sound pressure level
control means does not adjust the first sound pressure level and the second sound pressure level,
the voice from the low efficiency speaker is recognized in the user's consciousness, Presence can
be sustained.
[0023]
Here, in order to solve the problems described above, the audio signal adjustment device
according to the present invention is a speaker having different sound generation efficiency, and
is a sound supplied to at least one low efficiency speaker and one high efficiency speaker An
audio signal adjusting apparatus for adjusting a signal, the first adjusting means for adjusting the
volume of an audio signal supplied to the low efficiency speaker, and the second adjusting means
for adjusting the volume of an audio signal supplied to the high efficiency speaker And a first
sound pressure level, which is a sound pressure level of the audio signal supplied to the low
efficiency speaker adjusted by the first adjustment unit, in the predetermined range of the
command volume level for the low efficiency speaker, the supplied audio signal First sound
pressure level control means having a maximum value regardless of the frequency of the second
adjustment means, and the second adjustment means in a predetermined range of the command
sound volume level for the high efficiency speaker A second sound pressure level is the sound
pressure level of the supply audio signals to the high efficiency speaker is adjusted Wait, and a
second sound pressure level control means for adjusting in accordance with the frequency of the
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supply audio signals.
[0024]
That is, from the viewpoint of adjusting the sound pressure level for each frequency of the audio
signal by adjusting the frequency characteristics of the equalizer etc., the first sound pressure
level control means determines the maximum value regardless of the frequency of the supplied
audio signal. By doing this, the first sound pressure level is made equal to or higher than the
second sound pressure level at which sound pressure level adjustment for each frequency is
performed by the second sound pressure level control means.
By doing this, it is possible to make it easy for the user to hear the sound from the low efficiency
speaker.
[0025]
In the sound signal adjusting apparatus described above, localization control for controlling a
supplied sound signal to the high efficiency speaker so that a sound image by sound from the
high efficiency speaker is localized at a place where the low efficiency speaker is located. The
means may be further provided. By this localization control means, it is possible to make the user
recognize the presence of the low efficiency speaker more strongly, thereby making it possible to
more efficiently appeal the voice from the low efficiency speaker to the user's hearing.
[0026]
Here, as a low efficiency speaker to the above-mentioned, the flat panel speaker which generates
an audio | voice by vibrating a planar structure can be illustrated. Although a flat panel speaker
may be a structure relatively larger than a high efficiency speaker in some cases, its directivity is
wide because it generates sound by vibrating a planar structure. However, the sound generation
efficiency is relatively low due to the large structure serving as the vibration source. Then, it
becomes possible to form a good sound field and a sound image by combining a flat panel
speaker and a high efficiency speaker, and in such a case, the audio signal adjusting device
according to the present invention is very useful.
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[0027]
Therefore, the audio signal adjustment device according to the present invention described
above, one or more audio signal supply devices for supplying an audio signal to the audio signal
adjustment device, and a volume by the first adjustment means of the audio signal adjustment
device. And one or more low efficiency speakers supplied with an audio signal whose frequency
is adjusted, and one or more high efficiency speakers supplied with an audio signal whose
volume is adjusted by the second adjustment means of the audio signal adjustment device , The
configuration of the audio system is possible.
[0028]
Furthermore, this audio system can also be applied to an on-vehicle audio system mounted in the
interior of a vehicle, in which case, for example, the low efficiency speaker generates sound by
vibrating the ceiling plate of the vehicle. It may be a ceiling speaker.
Further, the high efficiency speaker may be a speaker provided on front and rear vehicle
structures such as left and right door parts and / or a dashboard of the vehicle, for example, a
cone type speaker.
[0029]
In the case of simultaneously reproducing sound with a plurality of types of speakers having
different sound generation efficiencies, it is possible to make the volume at the low efficiency
speaker more appropriate while suppressing problems such as sound cracking.
[0030]
Here, an embodiment of an audio signal adjustment device according to the present invention
and an on-vehicle audio system configured by applying the audio signal adjustment device will be
described based on the drawings.
[0031]
1 and 2 show a schematic configuration of an on-vehicle audio system in a vehicle 1 on which an
audio signal adjustment device 30 according to the present invention is mounted.
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FIG. 1 is a side view of the vehicle 1, and FIG. 2 is a top view of the vehicle 1.
Two rows of seats are provided in the cabin of the vehicle 1, and a head unit 10 constituting an
on-vehicle audio system is incorporated in a dashboard in front of the seats in the front row.
Furthermore, at the foot of the front passenger seat, an audio signal adjustment device
(hereinafter referred to as "separate amplifier") 30 according to the present invention, which
constitutes an on-vehicle audio system, is disposed.
[0032]
The head unit 10 and the separate amplifier 30 are electrically connected to each other via an invehicle LAN installed in the vehicle 1. Further, the separate amplifier 30 has a ceiling speaker 40
provided on the ceiling of the vehicle 1 and a door speaker 50 provided on four places on the left
and right doors of the vehicle 1 (two on the left and right of the front door and two on the left
and right of the rear door). And connected. The ceiling speaker 40 is configured of a ceiling plate
40 b of the vehicle 1 and an exciter 40 a connected thereto. The exciter 40a vibrates by the drive
current supplied from the separate amplifier 30, whereby the ceiling plate 40b is excited to
generate sound. On the other hand, the door speaker 50 is a so-called cone type box speaker.
[0033]
As described above, in the vehicle 1, by providing the ceiling speaker 40 in addition to the door
speaker 50, the sound field formed in the vehicle compartment can be brought closer to the head
of the user (passenger), and thereby the user's The use environment of the in-vehicle audio
system is improved. In addition, since the ceiling speaker 40 generates a voice by exciting the
relatively large ceiling plate 40b, the directivity of the voice is wide, and the sense of spread can
be given to the voice formed in the vehicle interior. Since the ceiling speaker 40 is mainly
configured by the ceiling plate 40b, the ratio of occupying the space in the vehicle 1 is small, and
the habitability thereof is not impaired.
[0034]
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However, as described above, the generation of the sound in the ceiling speaker 40 is due to the
vibration of the ceiling plate 40b by the exciter 40a, while the generation of the sound of the
door speaker 50 is due to the cone inside. The voice generation efficiency of the voice of the door
speaker 50 is lower than the voice generation efficiency of the door speaker 50. Therefore, the
separate amplifier 30 according to the present invention and the on-vehicle audio system
including the same are formed in consideration of the difference in the sound generation
efficiency between the ceiling speaker 40 and the door speaker 50.
[0035]
FIG. 3 shows a schematic configuration of the in-vehicle audio system. The head unit 10
transmits / receives information to / from the operation unit (usually configured by operation
buttons, touch panel display, etc.) 11 and a separate amplifier 30 for the user in the vehicle 1 to
issue a request to the in-vehicle audio system Communication unit 12 for performing control and
a control unit 13 for controlling a plurality of audio signal supply devices (hereinafter referred to
as "audio source") provided in the head unit 10, which are connected to each other by a control
bus It is done. Furthermore, the control unit 13 controls the switching device 20 to alternatively
select one audio source from the plurality of audio sources connected via the control bus as the
audio source for output, and the communication unit The audio signal from the output audio
source is supplied to the separate amplifier 30 through 12.
[0036]
Here, as an audio source, a CD / DVD deck (hereinafter simply referred to as a "CD deck"). Hard
disk drive (hereinafter referred to as "HDD"). ) Is provided. When a user operating the vehicle 1
mounts a music CD in which music data is recorded on the CD deck 15, the control unit 13
selects the CD deck 15 as an output audio source via the switching device 20, and Data is
sampled from the CD, and an audio signal is supplied to the separate amplifier 30. At this time,
when the music CD mounted on the CD deck 15 is played for the first time in the vehicle 1, the
control unit 13 converts the music data into a predetermined compressed file format such as
ATRAC3 or MP3 and the like in the HDD 14 Record on By doing this, the control unit 13 records
music data in the HDD 14, and the user can arbitrarily record music data recorded in the HDD 14
even if a music CD is not attached to the CD deck 15. It becomes possible to reproduce and hear
in the vehicle 1. In the reproduction of the music data recorded in the HDD 12, the music data is
decoded and converted into a music signal by the decoding unit 21 provided in the head unit 10,
and supplied from the decoding unit 21 to the separate amplifier 30. It is done by
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[0037]
Furthermore, the head unit 10 is provided with a TV tuner 16, AM / FM tuner 17, an MD deck
18, and a cassette deck 19 as audio sources, each being controlled by the control unit 13 via a
control bus and switching It is electrically connected to the device 20. The user selects one of
them via the operation unit 11, and the control unit 13 supplies audio signals from the respective
media of TV, radio, MD, and cassette to the separate amplifier 30 and reproduces them in the
vehicle 1. It is possible. Further, it is also possible to record the audio signal obtained from each
medium in the HDD 14 in the same manner as the music CD as described above.
[0038]
Next, the separate amplifier 30 adjusts the audio signal supplied from the head unit 10 through
the communication unit 31 provided in the separate amplifier 30 and the communication unit 31
that communicates with the communication unit 12 of the head unit 10. Control unit 32 that
controls the respective constituent units. An adjustment series for ceiling speakers composed of a
volume control unit 41 for adjusting an audio signal finally supplied to the ceiling speaker 40, a
first equalizer 42, a second equalizer 43, and a current amplification unit 44 in the separate
amplifier 30. And two series of adjustment series of door speakers composed of a volume control
unit 51 for adjusting an audio signal finally supplied to the door speaker 50, a first equalizer 52,
a second equalizer 53, and a current amplification unit 54. It is done.
[0039]
The details of each component in the ceiling speaker adjustment series and the door speaker
adjustment series will be described below. The volume control unit 41 and the volume control
unit 51 control the sound pressure level with respect to the commanded volume level of the
audio required for the ceiling speaker 40 and the door speaker 50. The command volume level is
the volume of the sound given to the speakers from the operation unit 11 of the head unit 10 by
the user in the vehicle cabin. In this embodiment, the user can specify the command volume level
in 64 steps from 0 to 63, where 0 is the minimum volume and 63 is the maximum volume. The
signal of the command sound volume level is passed from the operation unit 11 through the
communication units 12 and 31 to the control unit 32 of the separate amplifier 30, and the
control unit 32 controls the volume control units 41 and 51 based thereon.
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[0040]
Here, a specific adjustment method of the sound pressure level by the volume control unit 41
and the volume control unit 51 is shown in FIG. 4 and FIG. FIG. 5 is a table showing specific
numerical values of the sound pressure levels of the door speaker 50 and the ceiling speaker 40
with respect to the command volume level, and FIG. 4 is a graph of the same. The line L1 in FIG.
4 represents the transition of the sound pressure level of the door speaker 50, and the lines L2
and L3 represent the transition of the sound pressure level of the ceiling speaker 40. In addition,
the point which has two lines showing transition of the sound pressure level of the ceiling
speaker 40 is mentioned later. Further, in the present embodiment, the command sound volume
level is basically displayed five by five for the sake of simplicity, but the sound pressure level of
each speaker with respect to the command sound volume level not displayed in FIG. It is
interpolated.
[0041]
Here, as shown in FIG. 4, in the range (0 to 63) of command sound volume levels that can be
selected by the user, the sound pressure level at the ceiling speaker 40 is set higher than the
sound pressure level at the door speaker 50 . This is to make it easier for the user to hear the
sound from the ceiling speaker 40 in consideration of the fact that the sound generation
efficiency of the ceiling speaker 40 is lower than that of the door speaker 50. Furthermore, in the
range of low volume level from the command volume level to about 0 to 10, the ratio of the
sound pressure level to the command volume level (hereinafter referred to as ?sound pressure
level ratio?) The ratio is larger than the sound pressure level ratio of the door speaker 50.
Therefore, in the graph shown in FIG. 4, the slopes of the lines L2 and L3 are steeper than the
slope of the line L1 in the low volume level range. As described above, even if the sound pressure
level of the ceiling speaker 40 is suddenly changed, the volume command given to the ceiling
speaker is the low volume command, so the function of the ceiling speaker 40 is normally
maintained without problems such as sound cracking. It can be done.
[0042]
Next, the sound pressure level ratio of the ceiling speaker 40 is substantially the same as the
sound pressure level ratio of the door speaker 50 in the range of the middle sound volume level
from 10 to 40, and both sound pressure level ratios The value of is also adjusted to be
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substantially constant. Therefore, in the graph shown in FIG. 4, the slopes of the lines L1, L2 and
L3 are substantially constant in the range of the middle volume level, and there is linearity
between the command volume level and the sound pressure level. That is, in the middle volume
level range, unlike the low volume level range, by suppressing the sound pressure level ratio of
the ceiling speaker 40 to the same degree as the door speaker 50, a defect such as a sound break
occurs in the ceiling speaker 40. Suppress.
[0043]
Furthermore, in the range of the high volume level up to 40 to 63 (maximum value), the sound
pressure level of the ceiling speaker 40 is the same as the sound pressure level of the door
speaker 50 at the maximum command volume 63. The sound pressure level ratio of the ceiling
speaker 40 is adjusted. Therefore, in the graph shown in FIG. 4, in the range of the high volume
level, the slopes of the lines L2 and L3 become smaller than the line L1, and the lines converge to
0 dB at the maximum command volume level 63. As described above, by making the sound
pressure level of the ceiling speaker 40 the same as the sound pressure level of the door speaker
50, it is possible to suppress the generation of sound breakage caused by bringing the command
volume level close to the maximum value.
[0044]
Next, the first equalizer 42 and the first equalizer 52 adjust the frequency characteristics (the
characteristics of the sound pressure level with respect to the frequency) of the audio signal
supplied to the ceiling speaker 40 and the door speaker 50. Here, a specific adjustment method
of frequency characteristics by the first equalizer 42 and the first equalizer 52 is shown in FIG. 6
and FIG. FIG. 6 shows the relationship between the frequency of the audio signal and the
adjustment amount of the sound pressure level with respect to each frequency for each
instructed sound volume (lines L4 to L10). And FIG. 7 shows an adjustment mode (represented
by any one of lines L4 to L10 shown in FIG. 6) of the frequency characteristic adopted in the
door speaker 50 with respect to the command sound volume level and an adjustment of
frequency characteristic adopted in the ceiling speaker 40. The relationship with the aspect
(represented by any one of lines L4 to L10 shown in FIG. 6) is shown.
[0045]
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In FIG. 6, as the volume command level to the ceiling speaker 40 and the door speaker 50
increases, the adjustment mode of the frequency characteristic adopted by each speaker tends to
shift from the line L10 to the line L4. Furthermore, as shown in FIG. 7, at the same command
volume level, the adjustment mode of the frequency characteristic adopted by the ceiling speaker
40 is a mode in which the sound pressure level is higher than the sound pressure level in the
adjustment mode of the door speaker 50. Be done. For example, when the command sound
volume level to each speaker given through the operation unit 11 of the head unit 10 is 30, the
adjustment mode adopted by the door speaker 50 is represented by a line L8 from the table
shown in FIG. The adjustment mode adopted by the ceiling speaker 40 is represented by a line
L7. Accordingly, at this time, the control unit 32 controls the first equalizer 42 so that the first
equalizer 42 adjusts the frequency characteristic represented by the line L7, and the first
equalizer 52 adjusts the frequency characteristic represented by the line L8. The first equalizer
52 is controlled to perform the
[0046]
As described above, in the on-vehicle audio system configured by the separate amplifier 30
according to the present invention, the ceiling speaker is also used to adjust the frequency
characteristic of the audio signal in consideration of the difference in the sound generation
efficiency between the ceiling speaker 40 and the door speaker 50. The sound pressure level of
40 is set to the sound pressure level of the door speaker 50 or more. This makes it easier for the
user to recognize the sound from the ceiling speaker 40.
[0047]
Next, the second equalizer 43 and the second equalizer 53 also adjust the frequency
characteristics (the characteristics of the sound pressure level to the frequency) of the audio
signal supplied to the ceiling speaker 40 and the door speaker 50. However, these do not adjust
the frequency characteristics in consideration of the sound generation efficiency of the ceiling
speaker 40 and the door speaker 50 as described above, but perform adjustment based on the
user's preference. Specifically, in order to achieve the frequency characteristic requested by the
user via the operation unit 11 of the head unit 10, the audio signal to the ceiling speaker 40 and
the door speaker 50 has the same adjustment characteristic of the frequency characteristic.
Based on the control unit 32, the second equalizer 43 and the second equalizer 53 are controlled.
That is, the adjustment of the frequency characteristics performed by the second equalizers 43
and 53 is different from the adjustment of the frequency characteristics performed by the first
equalizers 42 and 52, and the difference in sound generation efficiency between the ceiling
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speaker 40 and the door speaker 50 is taken into consideration Instead, adjustment of the
frequency characteristics of the audio signal is performed.
[0048]
Finally, the current amplification unit 44 and the current amplification unit 54 respectively
include the audio signal adjusted by the volume control unit 41, the first equalizer 42, and the
second equalizer 43, the volume control unit 51, the first equalizer 52, and the second Each
audio signal is amplified so that the audio signal adjusted by the equalizer 53 is large enough to
drive the ceiling speaker 40 and the door speaker 50.
[0049]
As described above, by making the adjustment for the audio signal supplied to the ceiling
speaker 40 different from the adjustment for the audio signal supplied to the door speaker 50,
the problem of the sound breakup in the ceiling speaker 40 can be suppressed, and the ceiling
speaker 40 can be suppressed. Thus, it is possible to sufficiently compensate for the low sound
generation efficiency of the above and reproduce the sound from the sound source that the head
unit 10 has.
[0050]
Here, FIG. 8 shows an example of a flow of volume control on an audio signal from an audio
source, which is performed in the on-vehicle audio system configured of the separate amplifier
10 according to the present invention.
This volume control is mainly performed by the control unit 32 of the separate amplifier 30.
The details of the volume control will be described below.
[0051]
In S101, it is determined whether the in-vehicle audio system has been launched. Specifically, the
control unit 13 detects that the power switch provided on the head unit 10 side has changed
from the off state to the on state, and the control unit 32 acquires it via the communication units
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12 and 31. Then, the control unit 32 determines that the in-vehicle audio system has been
launched. If it is determined in S101 that the in-vehicle audio system is launched, the process
proceeds to S103, and if it is determined that the in-vehicle audio system is not launched, the
process proceeds to S102.
[0052]
In S102, in the on-vehicle audio system in which the power supply is in the ON state, it is
determined whether or not the audio source selected as the output audio source is switched
among the plurality of audio sources. Specifically, the control unit 13 monitors the output audio
source selected by the switching device 20, and when the selection destination is changed, a
signal indicating that there is a change is controlled via the communication units 12 and 31. It is
transmitted to the part 32. The control unit 32 performs the main determination based on the
signal. If it is determined in S102 that the audio source is switched, the process proceeds to
S103, and if it is determined that the audio source is not switched, the process proceeds to S105.
[0053]
In S103, adjustment of the sound pressure level by the sound volume control unit 41 and the
sound volume control unit 51 described above and adjustment of the frequency characteristics
by the first equalizer 42 and the first equalizer 52 are performed. At this time, the adjustment of
the sound pressure level in the volume control unit 41 is based on the relationship between the
command sound volume level and the sound pressure level represented by the line L3 shown in
FIG. 4, that is, the numerical value shown in the column of ?Ceiling Speaker VOL2? shown in
FIG. It is done on the basis of The transition of the sound pressure level represented by the line
L3 is set so that the sound pressure level is higher than the transition of the sound pressure level
represented by the line L2. The audio signal from the audio source subjected to these
adjustments is supplied to the ceiling speaker 40 and the door speaker 50 to reproduce the audio
in the vehicle cabin. At this time, the user inside the vehicle compartment can clearly recognize
the sound from the ceiling speaker 40 as described above. When the process of S103 ends, the
process proceeds to S104.
[0054]
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In S104, it is determined whether or not a predetermined time T1 has elapsed since the process
of S103 is started. The predetermined time T1 is a time for continuing the process of S103, and a
value suitable for the on-vehicle audio system may be set as appropriate. If it is determined that
the predetermined time T1 has elapsed, the process proceeds to S105, and if it is determined that
the predetermined time T1 has not elapsed, the process of S103 is performed again.
[0055]
In S105, the adjustment of the sound pressure level by the sound volume control unit 41 and the
sound volume control unit 51 described above and the adjustment of the frequency
characteristics by the first equalizer 42 and the first equalizer 52 are performed. At this time, the
adjustment of the sound pressure level in the volume control unit 41 is based on the relationship
between the command sound volume level and the sound pressure level represented by a line L2
shown in FIG. 4, that is, the numerical value shown in the column of ?Ceiling Speaker VOL1?
shown in FIG. It is done on the basis of The transition of the sound pressure level represented by
the line L2 is set so that the sound pressure level is lower than the transition of the sound
pressure level represented by the line L3. It is possible to clearly recognize the sound from the
ceiling speaker 40. After the processing of S105, the present control is ended.
[0056]
According to this control, it is possible to suppress the problem of the sound breakup in the
ceiling speaker 40 and sufficiently compensate for the low sound generation efficiency of the
ceiling speaker 40 so that the sound from the sound source of the head unit 10 can be
reproduced. Furthermore, when a predetermined condition is established at startup of the invehicle audio system or immediately after switching the audio source, the sound pressure level of
the ceiling speaker 40 in the volume control unit 41 is set to the sound pressure of the ceiling
speaker 40 at normal playback. Set higher than the level. By doing this, when the predetermined
condition is satisfied, it is possible to emphasize the presence of the ceiling speaker 40 again for
the user in the vehicle compartment, and as a result, in the user's consciousness, from the ceiling
speaker 40 Speech can be more clearly recognized. And once it is recognized, the presence of the
ceiling speaker 40 is fixed to the user's consciousness, and thereafter (after a predetermined time
T1 has elapsed) the sound pressure level of the ceiling speaker is adjusted to a low level
(however, even in this case, As shown in Fig. 4, the sound pressure level of the door speaker 50 is
not lowered.
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[0057]
In addition to the above-described volume control, sound images formed by sounds from the four
door speakers 50 provided in the vehicle 1 are localized at the position where the ceiling speaker
40 exists, ie, the position of the ceiling plate 40 b of the vehicle. Sound image localization control
may be performed. In this sound image localization control, for example, the control unit 32
raises the sound pressure level of a predetermined frequency of the audio signal to a component
(a component not shown in FIG. 3) constituting the door speaker adjustment series. Do. 7-8 kHz
is mentioned as an example of this predetermined frequency.
[0058]
Further, even if only the adjustment of the frequency characteristics shown in FIG. 6 is performed
on the ceiling speaker 40 and the door speaker 50 without performing the control of the sound
pressure level by the volume control units 41 and 51 described above, the ceiling speaker 40 and
the door It is possible to control the volume in consideration of the difference in the sound
generation efficiency of the speaker 50. At this time, for the ceiling speaker 40 with low sound
generation efficiency, regardless of the command volume level, based on the adjustment mode of
the frequency shown by line L4 in FIG. 6, that is, the sound pressure level regardless of the
frequency of the audio signal. Adjust the audio signal to -0 dB. In the door speaker 50, as shown
in the table of FIG. 7, the frequency characteristic of the audio signal is adjusted in accordance
with the command volume level. Also in this manner, it is possible to suppress the problem of
sound breakup in the ceiling speaker 40 and sufficiently compensate for the low sound
generation efficiency of the ceiling speaker 40 so that the sound from the sound source of the
head unit 10 can be reproduced. Become.
[0059]
FIG. 1 is a first view of a vehicle equipped with an on-vehicle audio system including an audio
signal adjusting device according to an embodiment of the present invention. It is a 2nd figure of
the vehicle by which the vehicle-mounted audio system comprised including the audio | voice
signal adjustment apparatus which concerns on the Example of this invention is mounted. FIG. 1
is a diagram showing a schematic configuration of an on-vehicle audio system including an audio
signal adjustment device according to an embodiment of the present invention. It is a graph
showing the relationship between the command sound volume level and the sound pressure level
in adjustment of the sound pressure level performed in the audio signal adjusting device
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according to the embodiment of the present invention. It is a table | surface corresponding to the
graph shown in FIG. It is a graph showing the relation between frequency and sound pressure
level in adjustment of the frequency characteristic performed in an audio signal adjustment
device concerning an example of the present invention. It is a table | surface which shows the
relationship between the instruction | command sound volume level, and the correction |
amendment aspect of the frequency characteristic employ | adopted as a ceiling speaker and a
door speaker in the audio signal adjustment apparatus which concerns on the Example of this
invention. It is a flowchart of sound volume control performed by the audio signal adjustment
device according to the embodiment of the present invention.
Explanation of sign
[0060]
1 иии Vehicle 10 и и и Head unit 30 и и и Audio signal adjustment device (separate amplifier) 32 и и и
Control unit 40 и и и Ceiling speaker 50 и и и Door speaker 41, 51 иии Volume control unit 42, 52 и и и
First equalizer
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