JP2010016574

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DESCRIPTION JP2010016574
An object of the present invention is to provide a mechanism for preventing input of an audio
signal clipped from a portable player to an audio reproducing device when the audio data in the
portable player is reproduced using an audio reproducing device. SOLUTION: A microcomputer
21 of an audio reproducing device 20 connected to a portable player 10 transmits a control
signal 40 to the portable player 10 to stop the operation of the equalizer of the portable player
10, and flat voice from the portable player 10 While outputting the signal 30, the equalizer
setting information set in the equalizer in the portable player 10 is read, the database 22 is
searched with the read equalizer setting information, and the corresponding frequency
characteristic information stored in advance is extracted. By converting into the filter coefficient
for the equalizer and setting it as the equalizer 23 in the audio reproduction device 20, the
frequency characteristic of the flat audio signal 30 output from the portable player 10 is
converted and reproduced through the amplifier 24. Do. [Selected figure] Figure 1
Audio reproduction system, audio reproduction apparatus, portable player and audio
reproduction control method
[0001]
The present invention relates to an audio reproduction system, an audio reproduction device, a
portable player, and an audio reproduction control method.
[0002]
BACKGROUND In recent years, it has become possible to play and enjoy music using a portable
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terminal (such as a portable music player or a portable telephone) while moving while out of the
office.
Also, in a portable terminal (such as a portable music player), digital audio in MP3 (MPEG-1
Audio Layer 3) format, which has the same sound quality as a CD (Compact Disc) and can be
compressed to reduce the file size. As data, there are many cases where digital processing is
performed on the side of a portable terminal (such as a portable music player).
[0003]
Furthermore, addition of a portable terminal (portable music player or portable telephone) as in
Japanese Patent Application Laid-Open No. 2001-67100 "MP3 portable player" of Patent
Document 1 so that the music to be reproduced can be output with the desired sound quality The
function also has an equalizer that is an adjustment means of frequency characteristics, and also
has an equalizer curve setting function that selects and sets a desired frequency characteristic
according to the genre of music (classic, pop, jazz, etc.) It has appeared.
[0004]
In such a case, digital music data is generally represented by a two's complement expression with
a value of less than 1 to -1 or more.
In addition, in the case of an equalizer that performs digital processing for adjusting frequency
characteristics (cuts, boosts, attenuates, etc. in frequency bands), equalization is performed after
the input level is reduced, or clipping is performed when equalizing is boosted. Use either
method.
[0005]
That is, for example, the device configuration in the case of a portable player in which a clip may
occur in equalization is as shown in FIG. FIG. 4 is a conceptual view showing an example of a
device configuration of a conventional portable player. A conventional portable player, as shown
in FIG. 4, includes a storage device 11 configured of an HDD, a RAM, and a flash memory, a
decoder 12 for decoding a compressed audio signal into an original audio signal, an equalizer 14
for adjusting frequency characteristics, and an analog It comprises a D / A converter 15 for
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converting into an audio signal and an amplifier 16 for amplifying an analog audio signal.
[0006]
Music data is read from a storage device 11 composed of an HDD, a RAM, a flash memory, etc.,
and if the read music data is a non-compressed music file, it is transmitted to the equalizer 14 as
it is. On the other hand, if the music data read from the storage device 11 is a compressed music
file, the decoder 12 decodes the original music data that has not been compressed and then
transmits the decoded music data to the equalizer 14.
[0007]
The equalizer 14 changes the frequency characteristic of the input music data to a desired
characteristic specified digitally, converts it back to analog voice data by the D / A converter 15
in the subsequent stage, and transmits it to the amplifier 16. The amplifier 16 amplifies the
volume to a desired level and outputs it from the headphones.
[0008]
FIG. 5 is a conceptual view showing another example of the configuration of the conventional
portable player, in which the attenuator 13 is disposed in front of the equalizer 14. In the case of
FIG. 4, the level of music data stored in the storage device 11 is input as it is to the equalizer 14
prior to equalization, but in the case of FIG. 5, the attenuator 13 is used prior to equalization.
After reducing the level of the music data, the music data is input to the equalizer 14 to prevent
the output data of the equalizer 14 from clipping due to the adjustment of the frequency
characteristic.
[0009]
Furthermore, in order to improve the usability (usability) of the above-mentioned portable
terminal (portable music player and portable telephone), the portable terminal is connected to,
for example, an on-vehicle audio reproducing device, and the storage device of the portable
terminal Listen to the music data stored in the PC in the vehicle, or connect it to a PC at home, an
audio playback device, etc., and play the music data stored in the storage device of the portable
terminal from the PC etc. It has also become possible to
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[0010]
For example, the portable player is connected to an on-vehicle audio reproducing device, and an
output signal (analog voice signal) from the amplifier 16 on the portable player side as shown in
FIGS. 4 and 5 is input to the on-vehicle audio reproducing device. In the case of reproducing by
the audio reproducing device, as shown in FIG. 4, if the boost is performed by equalizing without
reducing the input level, the clipped waveform may be output from the portable player as shown
in FIG. And an audio signal of such clip waveform is input to the audio reproduction device.
On the other hand, as shown in FIG. 5, when the input level is reduced prior to the equalization
on the portable player side, the S / N may be deteriorated or the volume may be reduced.
[0011]
FIG. 6 is a schematic view illustrating the output level of an audio signal output from the portable
player to an external audio reproduction device. As exemplified in FIG. 6, when the audio signal
from the portable player 10 is clipped and output as in the case of boosting by equalizing
processing without reducing the input level on the portable player 10 side, an audio
reproduction device When reproduced by 20, the sound quality of the output voice is degraded
and the sound seems to be broken. Also, once the clipped audio signal is input from the portable
player 10 to the audio reproduction device 20, there is no clip on the audio reproduction device
20 side even if the audio reproduction device 20 side is equipped with an equalizer function. It
can not be corrected to the state, and only the degraded voice (music) can be heard. JP-A-200167100 (page 3-4)
[0012]
The present invention has been made in view of the problem as described above occurring in the
prior art in the case of reproducing audio data of a portable player using an audio reproduction
device connected to the outside, and from the portable player side It is an object of the present
invention to provide a mechanism for preventing the input of an audio signal clipped to the audio
reproducing device side.
[0013]
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In order to solve the above-described problems, the audio reproduction system, the audio
reproduction device, the portable player, and the audio reproduction control method according
to the present invention adopt the following characteristic configurations.
[0014]
(1) An audio reproduction system in which a portable player having an equalizer and an audio
reproduction device are connected, and an audio signal stored in the portable player is
transmitted to the audio reproduction device and reproduced and output by the audio
reproduction device. The audio reproduction device reads equalizer setting information set in an
equalizer in the portable player by transmitting a control signal to the portable player, and
invalidates the operation of the equalizer in the portable player. As an audio signal not equalized
from the portable player is outputted to the audio reproducing device, the equalizer setting
information read from the portable player is converted into a filter coefficient to be set to an
equalizer in the audio reproducing device. That Audio reproduction system set to the equalizer of
Dio reproducing the instrument, by the equalizer, to reproduce by converting the frequency
characteristics of the audio signal outputted from the portable player.
(2) Frequency characteristics to be set in the equalizer in the audio reproduction device in a
format associated with each of the equalizer setting information set in the equalizer in the
portable player connected to the audio reproduction device in the audio reproduction device
Information is stored in advance, and based on the equalizer setting information read from the
connected portable player, the equalizer setting information stored in the database is searched
and associated with the matched equalizer setting information The audio reproduction system
according to (1), wherein the frequency characteristic information is extracted from the database,
the extracted frequency characteristic information is converted into the filter coefficient, and the
filter coefficient is set as an equalizer in the audio reproduction device.
(3) The frequency characteristic information stored in the database provided in the audio
reproducing device is an equalizer curve characteristic relating to an equalizer in the audio
reproducing device, or an element including a center frequency, Q, gain, and a filter type The
audio reproduction system according to (2) above, which is one of equalizer setting values. (4) In
an audio reproducing apparatus connected to a portable player having an equalizer and
transferring and reproducing audio data accumulated in the portable player, the portable player
is transmitted by transmitting a control signal to the portable player. Means for reading the
equalizer setting information set in the equalizer in the inside and transmitting a control signal to
the portable player makes the operation of the equalizer in the portable player invalid and the
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equalization is not performed from the portable player A means for outputting an audio signal to
the audio reproduction device, and the equalizer setting information read from the portable
player are converted into filter coefficients to be set in the equalizer in the audio reproduction
device, and the equalizer in the audio reproduction device is Set to the equalizer Ri, the audio
reproduction apparatus and a means for reproducing by converting the frequency characteristic
of the audio signal outputted from the portable player. (5) Frequency characteristic information
to be set in the equalizer in the audio reproduction device in a format associated with each of the
equalizer setting information that may be set in the equalizer in the portable player connected to
the audio reproduction device A database stored in advance is provided, and the equalizer setting
information stored in the database is searched based on the equalizer setting information read
from the connected portable player, and is associated with the matched equalizer setting
information. The audio reproduction device according to (4), wherein the frequency
characteristic information is extracted from the database, the extracted frequency characteristic
information is converted into the filter coefficient, and the filter coefficient is set as an equalizer
in the audio reproduction device. (6) The frequency characteristic information stored in the
database is either an equalizer curve characteristic related to an equalizer in the audio
reproduction device or an equalizer setting value including an element including a center
frequency, Q, gain, and a filter type. The audio playback device of (5) above. (7) Means for
converting and outputting the frequency characteristics of audio data recorded in the storage
device by the equalizer, means for connecting to an audio reproducing device, and transferring
the output audio data to the connected audio reproducing device And the audio data is recorded
in the storage device with the operation of the equalizer being invalidated based on the control
signal received from the audio reproducing device. A portable player that outputs to a playback
device and sends equalizer setting information set in the equalizer back to the audio playback
device.
(8) An audio reproduction system in which a portable player having an equalizer and an audio
reproduction device are connected, audio data stored in the portable player is transferred to the
audio reproduction device, and reproduced and output by the audio reproduction device A
method of controlling audio reproduction, comprising the steps of: outputting an audio signal not
equalized from the portable player to the audio reproduction device by disabling the operation of
the equalizer in the portable player; and setting the equalizer in the portable player Transferring
the equalizer setting information to the audio reproducing device, and converting the equalizer
setting information read from the portable player into a filter coefficient to be set to an equalizer
in the audio reproducing device, and the audio reproducing device An equalizer setting step of
setting the equalizer, by the equalizer, the audio reproduction control method and a step of
reproducing by converting the frequency characteristic of the audio signal outputted from the
portable player. (9) The audio reproduction device is set in the equalizer in the audio
reproduction device in a format associated with each of the equalizer setting information that
may be set in the equalizer in the portable player connected to the audio reproduction device. A
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database in which frequency characteristic information to be stored is stored in advance, and the
equalizer setting step stores the equalizer setting information stored in the database based on the
equalizer setting information read from the connected portable player The frequency
characteristic information associated with the equalizer setting information which has been
retrieved and matched is extracted from the database, the extracted frequency characteristic
information is converted into the filter coefficient, and is set to the equalizer in the audio
reproducing device ((8) Audio playback control method of) . (10) The frequency characteristic
information stored in the database provided in the audio reproduction device is an equalizer
curve characteristic regarding an equalizer in the audio reproduction device or an element
including a center frequency, Q, gain, and a filter type The audio reproduction control method
according to the above (9), which is any one of equalizer setting values.
[0015]
According to the audio reproduction system, the audio reproduction device, the portable player,
and the audio reproduction control method of the present invention, the following effects can be
obtained.
[0016]
In a state where no clip occurs, an audio signal is output from the portable player, and an audio
with a desired sound quality intended by the user can be reproduced by the equalizer function on
the audio reproducing device side.
Furthermore, since the clip does not occur in the output audio signal of the portable player,
adjustment can be made on the audio reproducing device side so that no sound break occurs.
[0017]
Hereinafter, preferred embodiments of an audio reproduction system, an audio reproduction
device, a portable player, and an audio reproduction control method according to the present
invention will be described with reference to the attached drawings. Here, the audio reproduction
device may be an on-vehicle audio reproduction device, may be an on-vehicle device shared with
the navigation system, or may be disposed in a home or an office It may be an audio reproducing
device or a PC (Personal Computer). The portable player may be a portable music player, a
portable telephone, a PHS (Personal handy-phone) terminal, or a portable notebook PC.
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[0018]
(Features of the Present Invention) Before describing the embodiments of the present invention,
the features of the present invention will first be outlined. According to the present invention,
when the music data of the portable player is reproduced from the connected audio reproduction
device, the operation of the equalizer on the portable player side is invalidated by control from
the audio reproduction device side, and the frequency characteristic is not changed from the
portable player side. Output a flat output signal, that is, an unequalized audio signal to the audio
playback device side, change the frequency characteristic by the equalizer function of the audio
playback device side, and output a voice with a desired sound quality. It is characterized by
[0019]
As a result, even audio data from the portable player can be reproduced as good quality audio
that can not be clipped in a state in which the audio reproduction device side performs
equalization of the frequency characteristics to the desired sound quality.
[0020]
First Embodiment First, an example of a system configuration of an audio reproduction system
according to the present invention is shown in FIG.
As shown in FIG. 1, in the audio reproduction system according to the present embodiment, a
portable player 10 and an audio reproduction device 20 are connected, and an audio signal 30
from the portable player 10 is transferred to the audio reproduction device 20 to transmit the
audio reproduction device 20. It shows the case of playing by the side. Here, as a connection
signal format between the portable player 10 and the audio reproduction device 20, an analog
signal format or a digital signal format may be used. In the case of connection by digital signal
format, although not shown in FIG. 1, a D / A converter for converting into an analog audio signal
is disposed at the front stage of the amplifier on the audio reproduction device 20 side.
[0021]
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Here, although not shown, the portable player 10 is provided with an equalizer capable of
adjusting (cut, boost, attenuate) frequency characteristics as described in FIGS. 4 and 5 of the
prior art. However, the operation of the equalizer can be controlled by an external control signal
(for example, the control signal 40 from the audio playback device 20). For example, according to
the control signal 40 from the audio reproducing device 20, the equalizer setting information set
in the equalizer on the portable player 10 side is transferred to the request source, or the
operation of the equalizer on the portable player 10 side is invalidated. It is configured to be able
to output an audio signal that has not been equalized.
[0022]
On the other hand, the audio reproducing device 20 includes a CPU 21, a microcomputer 21
composed of a memory, a database 22 composed of an HDD and a flash memory, an equalizer 23
having an adjustment function (cut, boost, attenuate) of frequency characteristics of audio
signals, and an output level of audio signals. And at least an amplifier 24 for adjusting the
[0023]
The microcomputer 21 in the audio reproducing device 20 transmits a control signal 40 to the
portable player 10 of the connection destination, acquires equalizer setting information on the
portable player 10 side, and stores it in the database 22 or the portable player 10 side. Control to
disable the operation of the equalizer and output a flat audio signal, that is, an audio signal that
has not been equalized, equalizer setting information obtained from the portable player 10 side is
read from the database 22, and is output to the equalizer 23. At least control to convert into
information to be set (filter coefficient) and set it to the equalizer can be performed.
[0024]
In addition, in order to efficiently carry out the control on the audio reproducing device 20 side,
an equalizer which may be set to each of the portable players 10 for all the portable players 10
which may be connected to the audio reproducing device 20 The curve characteristics are stored
in advance in the database 22 on the audio reproducing device 20 side in association with the
equalizer setting information set for each portable player 10.
[0025]
After that, when the portable player 10 is connected to the audio reproducing device 20, the
audio reproducing device 20 transmits the control signal 40 from the microcomputer 21 to
thereby set the equalizer setting information set in the connected portable player 10 get.
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In addition, the control signal 40 is transmitted from the audio playback device 20 to the
connected portable player 10, the equalizer function on the portable player 10 side is set to be
invalid, and the flat audio signal 30 is equalized. Control to output no sound signal.
[0026]
Furthermore, the equalizer setting information stored in advance in the database 22 is searched
by the equalizer setting information acquired from the portable player 10, and the equalizer
curve characteristic associated with the equalizer setting information is read out. The filter
coefficient of the equalizer 23 is converted and set in the equalizer 23.
[0027]
As a result, the flat audio signal 30 (audio signal 30 which is not clipped) from the portable
player 10 is input to the audio reproducing device 20 side and read from the database 22 in the
equalizer 23 on the audio reproducing device 20 side. Based on the equalizer curve
characteristic, the frequency characteristic is converted to a desired sound quality, and the
amplifier 24 of the audio reproduction device 20 adjusts and outputs an appropriate volume.
[0028]
(Effects According to the Present Embodiment) Since the equalizer function of the portable player
10 is stopped, the audio signal 30 from the portable player 10 is output to the audio
reproduction device 20 without clipping, and the portable player 10 side Since the frequency
characteristic of the equalizer 23 on the audio reproduction device 20 side is adjusted based on
the equalizer setting information set in the above, it is possible to reproduce the sound with the
desired sound quality intended by the user.
Furthermore, since a clip does not occur in the output sound signal of the portable player 10, no
sound break occurs in the reproduced sound.
[0029]
Second Embodiment In the first embodiment, an example is shown in which equalizer curve
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characteristics are stored in the database 22 on the audio playback device 20 side as frequency
characteristic information to be associated with equalizer setting information of the portable
player 10 to be connected. However, the frequency characteristic information stored in the
database 22 may be the filter coefficient itself to be set in the equalizer 23. Alternatively, as
shown in FIG. 2, the equalizer setting values (center frequency f0, Q, gain Gain, type of filter Etc.)
may be stored.
FIG. 2 is a block diagram showing a different example of the system configuration of the audio
reproduction system according to the present invention, and shows the case where the
information stored in the database 22 is different from that of FIG.
[0030]
The microcomputer 21 of FIG. 2 calculates the filter coefficient to be reflected to the equalizer 23
from the equalizer setting value read from the database 22 and sets the filter coefficient to the
filter of the equalizer 23, as in the first embodiment. In addition, the frequency characteristic is
converted so as to obtain the desired sound quality, and the amplifier 24 of the audio
reproduction device 20 can be adjusted to an appropriate volume and output.
[0031]
Third Embodiment FIG. 3 is a block diagram showing still another example of the system
configuration of the audio reproduction system according to the present invention, and in this
embodiment, the audio from the portable player 10 to the audio reproduction device 20 side is
shown. It shows the case where the signal 30 is input without dropping the output level.
[0032]
Since the range that can be expressed in digital form is, as described above, less than 1 to -1, in
order to boost a certain frequency band, it is also possible to reduce the level of other
frequencies. is there.
In the conventional portable player shown in FIG. 5, a scheme is employed in which the overall
level is reduced by the attenuator 13 set in the previous stage of the equalizer 14 and the band
boosted by the equalizer 14 is increased. The output of will also be smaller.
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[0033]
However, as in the first and second embodiments described above, when playing back on the
audio playback device 20 side, the equalizer on the side of the portable player 10 is disabled and
the flat audio signal 30, that is, equalizing It is not necessary to reduce the overall level of the
audio signal by the attenuator 13 on the portable player 10 side as shown in FIG.
As described above, the audio reproduction device 20 in FIG. 3 receives a flat audio signal whose
output level is not attenuated from the portable player 10, and uses the equalizer 23 on the
audio reproduction device 20 side to obtain the desired sound quality. Good voice can be played
back.
[0034]
That is, the following effects can be obtained in the present embodiment.
When the connection between the portable player 10 and the audio reproduction device 20 is
analog, the unattenuated audio signal is more resistant to noise than the attenuated audio signal.
As a result, the S / N is improved. On the other hand, when the connection between the portable
player 10 and the audio reproduction device 20 is in digital form, the unattenuated audio signal
is wider in bit width than the attenuated audio signal. As a result, a delicate expression is possible
without the occurrence of bit loss.
[0035]
The configuration of the preferred embodiment of the present invention has been described
above. However, it should be noted that such examples are merely illustrative of the present
invention and do not limit the present invention in any way. It will be readily understood by
those skilled in the art that various modifications and variations can be made according to a
particular application without departing from the scope of the present invention.
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[0036]
It is a block diagram which shows an example of a system configuration ¦ structure of the audio
reproduction system by this invention. It is a block diagram which shows the different example of
the system configuration ¦ structure of the audio reproduction system by this invention. It is a
block diagram which shows the further another example of the system configuration ¦ structure
of the audio reproduction system by this invention. It is a conceptual diagram which shows an
example of a structure of the conventional portable player. It is a conceptual diagram which
shows the example from which the structure of the conventional portable player differs. It is a
schematic diagram explaining the output level of the audio ¦ voice signal output to an external
audio reproduction apparatus from a portable player.
Explanation of sign
[0037]
DESCRIPTION OF REFERENCE NUMERALS 10 portable player 11 storage device 12 decoder 13
attenuator 14 equalizer 15 D / A converter 16 amplifier 20 audio reproducing device 21
microcomputer 22 database 23 equalizer 24 amplifier 30 audio signal 40 control signal
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