JP2008288713A - Vehicle-mounted sound reproduction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To listen to a different audio content while keeping a comfortable state by eliminating unpleasantness due to a change in a sound field and variation in frequency characteristics that one of front and rear seats causes to the other. <P>SOLUTION: A vehicle-mounted sound reproduction system has a control unit 15 which monitors audio signals at the front and rear seats at any time and sequentially controls sound volume and frequency characteristics at one of the front and rear seats at any time according to sound volume and frequency characteristics at the other to reproduce and output sounds, thereby reproducing the sounds independently at the front and rear seats in the space of a cabin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle audio system capable of reproducing audio independently at front and rear seats in a vehicle interior space.

2. Description of the Related Art Conventionally, an in-vehicle audio reproduction system that can reproduce audio independently at front and rear seats in a vehicle interior space is known. For example, in an in-vehicle acoustic system, when passengers in the front and rear seats enjoy different contents, the sound generated by the rear-seat speaker is muted so that the corresponding contents can be heard clearly. Some of them provide an audio signal of rear seat content via a rear seat monitor (see, for example, Patent Document 1).
In addition, in an in-vehicle acoustic system with a heavy bass reproduction speaker (subwoofer), when the passengers in the front and rear seats enjoy different contents, the connection to the subwoofer is cut off, and the change in the sound field due to the subwoofer cutout is corrected. In other words, each passenger obtains audio information without feeling uncomfortable on hearing (see, for example, Patent Document 2).

JP 2006-248253 A JP 2003-158789 A

  However, according to the technique disclosed in Patent Document 1 described above, in order to mute the sound output from the rear-seat side speaker, the rear-seat occupant has the frequency characteristics and sound field feeling of sound that should originally be obtained. It is not possible to get it, and this may make you feel uncomfortable. In addition, when a passenger in the rear seat listens to a sound different from that in the front seat using, for example, headphones, the passenger in the front seat who is a speaker listens to the sound due to high-frequency sound leakage caused by the sound of the headphones. There was a problem that I could feel pleasure.

  On the other hand, according to the technique disclosed in Patent Document 2, since the audio signal that is normally listened to changes every moment, for example, at the moment when the volume level of the bass emitted by the speaker suddenly increases, However, there is a problem that listeners feel uncomfortable because of feeling uncomfortable or high-frequency sound leaking from headphones.

  The present invention has been made to solve the above-described problems, and eliminates discomfort that is felt based on changes in the sound field and frequency characteristics caused by the sound of one of the front and rear seats acting on the other, making it possible to comfortably enjoy different sound contents. An object of the present invention is to provide an in-vehicle audio reproduction system that can be listened to while maintaining a simple state.

  In order to solve the above-described problems, the in-vehicle audio reproduction system according to the present invention sequentially monitors audio signals at the front and rear seats, and sequentially controls the volume and frequency characteristics of the other seat according to the volume and frequency characteristics of one seat. Thus, a control unit for reproducing and outputting is provided, and independent sounds are reproduced at the front and rear seats in the vehicle interior space.

  Further, the in-vehicle audio reproduction system of the present invention can reproduce audio independently at the front and rear seats of the vehicle interior space, and the audio signal generated and output by the audio input source at one seat and the other seat. An input unit that captures an audio signal to be reproduced and output as an external input, and an audio signal that is captured via the input unit are sequentially monitored at the front and rear seats, and according to the volume and frequency characteristics at one seat, A control unit that sequentially controls and reproduces frequency characteristics, and an output unit that outputs an audio signal output by the control unit by switching an output destination based on an instruction from a passenger.

  According to the present invention, there is no inconvenience to remember based on changes in the sound field and frequency characteristics caused by one sound in the front and rear seats on the other, and it is possible to listen to different sound contents while maintaining a comfortable state. An audio playback system can be provided.

Embodiment 1 FIG.
FIG. 1 is a diagram schematically showing an example of a vehicle equipped with an in-vehicle audio reproduction system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the vehicle 1 is mounted with speakers indicated by FL / FR on the left and right of the front seat and RL / RR on the left and right of the rear seat. Furthermore, a subwoofer indicated by SW, or although not shown, a large number of speakers may be mounted such as a center speaker installed in front of the front seat. In addition, the vehicle 1 includes a front control unit 10 (hereinafter referred to as a user interface such as an operation unit or a display for the passenger to input various selection instructions and operation instructions at a position where the front seat passenger can easily operate. A head unit 10).

  Further, the vehicle 1 uses a headphone indicated by HP, which is used when different contents are enjoyed in the front seat and the rear seat in a position that allows the passenger in the rear seat to enjoy content including images. There is provided a rear control unit 20 having a function for the purpose. Further, the rear control unit 20 may be provided with an independent speaker, and further provided with a user interface such as an operation unit and a display for the rear seat passenger to input various selection instructions and operation instructions. Also good.

  FIG. 2 is a block diagram showing an internal configuration of the head unit 10 in the in-vehicle audio reproduction system according to Embodiment 1 of the present invention. Here, the block of the video control system is omitted, and only the block of the audio control system is extracted and shown.

  As shown in FIG. 2, the head unit 10 includes a tuner unit 11 including a TV tuner and a radio tuner, and recording of a CD (Compact Disc), an MD (Mini Disc), a DVD (Digital Versatile Disc), and the like. A disk unit 12 that reproduces audio data recorded on a medium and a plurality of input sources such as an external audio input 13 (external input terminal) are connected, and audio input by these input sources is captured by the input unit 14.

  The input unit 14 includes an input source selection unit 141 that selects and takes in an analog audio signal that is reproduced and output from each of the above audio input sources based on a passenger's instruction, and an analog signal that is output via the input source selection unit 141. Is converted to a digital signal and output to the control unit 15. The analog digital conversion unit (ADC 142) is included. The input unit 14 further receives an audio signal output from the rear control unit 20 and supplies it as an external input (AUX).

The control unit 15 sequentially monitors the audio signals acquired by the input unit 14 at the front and rear seats, sequentially controls the volume and frequency characteristics of the other seat according to the volume and frequency characteristics of one seat, and outputs to the output unit 16. Supply. Details of the internal configuration and the like will be described later with reference to FIG.
The output unit 16 converts the digital signal output from the control unit 15 into an output signal by switching the output destination based on an instruction from the passenger, and converts the digital signal output via the output selection unit 161 into an analog signal. And a digital-to-analog converter (DAC 162) that outputs to connected speakers FL, FR, RL, RR, SW, or headphones HP.

  In addition, although the above-mentioned structure was demonstrated as what the head unit 10 is equipped with, the rear control unit 20 shall be equipped with the same structure. In this case, the audio signal output by the head unit 10 is acquired as an external input (AUX).

  FIG. 3 is a block diagram showing an example of the internal configuration of the control unit 15 shown in FIG. The control unit 15 is configured by, for example, a microprocessor, and is configured by a frequency characteristic measurement unit 151, a comparison calculation unit 152, and an audio adjustment unit 153 so that the internal configuration is expanded and shown in FIG. .

  The frequency characteristic measuring unit 151 receives the front seat side audio signal and the rear seat side audio signal captured by the input unit 14 (ADC 142) as inputs, and sequentially measures (monitors) the volume level in several frequency bands of the audio. The voltage is supplied to one input terminal of the comparison calculation unit 152. The comparison calculation unit 152 has a function of sequentially comparing the frequency characteristic monitored by the frequency characteristic measurement unit 151 with a predetermined frequency characteristic set in advance, and supplying the result to the sound adjustment unit 153.

The sound adjustment unit 153 extracts a change in volume level of a specific frequency band in which the sound at one seat affects the listening of the sound at the other seat according to the output of the comparison calculation unit 152, and the extracted one The volume level of a specific frequency band of the voice is adjusted (Vol: volume adjustment and EQ: eco-rising processing) and supplied to the output unit 16 (output selection unit 161).
In FIG. 3, solid line arrows indicate audio signals, and dotted line arrows indicate control signals.

FIG. 4 is a flowchart showing the operation of the in-vehicle audio reproduction system according to Embodiment 1 of the present invention. Here, the operation of the control unit 15 in the head unit 10 is mainly extracted and shown.
Hereinafter, the operation of the in-vehicle audio reproduction system according to Embodiment 1 of the present invention shown in FIGS. 1 to 3 will be described in detail with reference to the flowchart of FIG.

First, the control unit 15 determines whether or not the audio contents being reproduced in the front seat and the rear seat are different (step ST401). Whether or not the content of the audio content to be listened to is different between the front seat and the rear seat can be determined by referring to the content of the external input 14 captured by the input unit 14.
Here, when it is determined that they are different (step ST401 “YES”), the frequency characteristic that the frequency characteristic measuring unit 151 sequentially monitors by the comparison calculation unit 152 and data indicating a predetermined frequency characteristic set in advance are displayed. (Hereinafter referred to as threshold data) is compared (step ST402). If it is determined that the audio contents listened to in the front seat and the rear seat are the same (step ST401 “NO”), the process is terminated without comparing the frequency characteristics (step ST406).

  It is assumed that the frequency characteristic measuring unit 151 sequentially measures the volume level of each frequency band and supplies it to one input terminal of the comparison operation unit 152. The frequency band measured here may be fixed in advance to a frequency band in which the sound output at one seat in the front and rear seats affects the sound listening at the other seat, such as the high sound range and the low sound range, for example. Alternatively, it may be dynamically changed by designation of the passenger. Further, as the threshold value, a volume level at which the speaker output affects the listening of the sound by the headphone HP or a volume level at which the headphone output affects the listening of the sound by the speaker is measured in advance, and the other input of the comparison calculation unit 152 is measured. It shall be supplied to the end.

  The comparison calculation result by the comparison calculation unit 152 is supplied to the sound adjustment unit 153. When the comparison operation unit 152 determines that the volume level measured by the frequency characteristic measurement unit 151 is greater than the threshold (step ST403 “YES”), the audio adjustment unit 153 receives the input acquired via the input unit 14. If the volume level of the sound is adjusted and supplied to the output unit 16 (step ST404), and the comparison calculation unit 152 determines that the volume level measured by the frequency characteristic measurement unit 151 is smaller than the threshold value (step ST403 " NO "), and the process is terminated without performing adjustment according to the comparison result (step ST405).

  The digital signal that has been subjected to volume level adjustment output by the control unit 15 (volume adjustment unit 153) is supplied to the output unit 16, where it is converted into an analog signal, and connected to a speaker or headphones connected based on a passenger's instruction. Is output.

  Here, the volume level adjustment process (step ST404) described above will be specifically described. Here, the front seat occupant listens to the audio content A through the speakers FL / FR and RL / RR (which may include the subwoofer SW, etc.), and the rear seat occupant receives the audio content B different from A through the headphone HP. The case of listening is assumed.

Under the above-described audio content listening environment, for example, when a heavy bass region of the audio content A is suddenly augmented and reproduced at a certain moment, conventionally, the rear seat passenger has different audio content from the desired audio content B. Under the influence of A, the user listened to an audio signal whose deep bass range was unnaturally enhanced, and felt uncomfortable and uncomfortable.
On the other hand, according to the first embodiment of the present invention, the audio adjustment unit 153 allows the audio content A to be duplicated by appropriately giving a preset threshold value to the control unit 15 (comparison operation unit 152). Equalizing (attenuation processing of the volume level in the heavy bass region of the frequency characteristics) is performed so as to suppress the volume level in the heavy bass region of the audio content A at the moment when the bass region is sharply enhanced. For this reason, the rear seat occupant can listen to the audio content B with the same frequency characteristics as before, and thus can reduce discomfort and discomfort.

  In addition, at the moment when the bass of the audio content B is suddenly enhanced and reproduced, the audio adjustment unit 153 that receives the comparison calculation result by the comparison calculation unit 152 performs equalization (specification to suppress the volume level of the bass of the audio content B. Equalization (volume level in a specific frequency band) that increases the overall volume level of the audio content B so that the influence of the audio content A is relatively reduced. , The audio contents A and B can be listened to with the same frequency characteristics as before. Therefore, both the passengers in the front and rear seats can listen to the audio content without feeling uncomfortable or uncomfortable.

As described above, according to the in-vehicle audio reproduction system according to Embodiment 1 of the present invention, when listening to different contents in the front seat and the rear seat in the vehicle interior space, the audio signals of both contents are monitored (frequency Measurement of the characteristics), and by controlling the volume level and frequency characteristics of the other according to the volume level and frequency characteristics of one, the uncomfortable feeling due to changes in the sound field and frequency characteristics that one affects the other is reduced As a result, it is possible to simultaneously listen to different audio contents while maintaining a comfortable state.
In addition, although the above-mentioned equalizing process was demonstrated as what the audio | voice adjustment part 153 performs automatically, it can also be performed manually by the passenger | crew's volume adjustment. As a result, fine adjustments can be made in accordance with the operation status of the vehicle, and an adaptive control that can form an optimal sound field or set frequency characteristics is possible.

Further, according to the first embodiment of the present invention described above, the case where only the head unit 10 is illustrated and the sound heard by one of the front and rear seats is adjusted has been described, but the rear control unit 20 performs the same control. By performing the same control in both or both, the passengers in the front and rear seats can listen to the audio content without further discomfort and discomfort in the vehicle interior space.
Further, the functions of the input unit 14 and the control unit 15 are combined into one control device, and the control unit is connected between the head unit 10 having the output unit 16 and the rear control unit 20. The on-vehicle audio reproduction system described above may be constructed by controlling both of the control units 20.

According to the first embodiment of the present invention, the front seat passenger listens to the audio content A through the speakers FL / FR and RL / RR, and the rear seat passenger uses the headphones HP to differ from the audio content A. The description has been made assuming that B is listened to, but the rear seat passenger is not limited to listening with headphones HP, and the same effect can be obtained when listening with a speaker mounted exclusively for the rear seat, for example. Is.
In the first embodiment of the present invention described above, data processing in the control unit 15 (frequency characteristic measurement unit 151, comparison operation unit 152, and sound adjustment unit 153) constituting the head unit 10 is performed by one or a plurality of data processing. It may be realized on a computer by a program, or at least a part thereof may be realized by hardware.

It is the figure which showed typically an example of the vehicle by which the vehicle-mounted audio | voice reproduction | regeneration system which concerns on Embodiment 1 of this invention is mounted. It is a block diagram which shows the internal structure of a head unit among the vehicle-mounted audio | voice reproduction | regeneration systems which concern on Embodiment 1 of this invention. It is a block diagram which shows an example of an internal structure of the control part shown in FIG. It is a flowchart which shows operation | movement of the vehicle-mounted audio | voice reproduction | regeneration system which concerns on Embodiment 1 of this invention.

Explanation of symbols

  1 vehicle, 10 front control unit (head unit), 11 tuner unit (audio input source), 12 disk unit (audio input source), 13 external input (AUX), 14 input unit, 15 control unit, 16 output unit, 20 Rear control unit, 141 input selection unit, 142 analog digital conversion unit (ADC), 151 frequency characteristic measurement unit, 152 comparison operation unit, 153 audio adjustment unit, 161 output selection unit, 162 digital analog conversion unit (DAC).

Claims (6)

An in-vehicle audio reproduction system capable of reproducing audio independently at front and rear seats in a vehicle interior space,
A control unit that sequentially monitors the sound at the front and rear seats, and sequentially controls and reproduces the volume and frequency characteristics of the other seat according to the volume and frequency characteristics of one seat,
An in-vehicle audio reproduction system comprising: The controller is
A frequency characteristic measurement unit that sequentially measures volume levels in several frequency bands of the sound;
A comparison operation unit that sequentially compares the frequency characteristic measured by the frequency characteristic measurement unit and a predetermined frequency characteristic set in advance;
A change in volume level of a specific frequency band in which the sound at one seat affects the listening of the sound at the other seat is extracted according to the output of the comparison operation unit, and the specific frequency of the extracted one sound An audio adjustment unit that adjusts the volume level of the band,
The in-vehicle audio reproduction system according to claim 1, further comprising: An input source selection unit that selects and takes in an analog audio signal generated and output by an audio input source based on a passenger's instruction, and an analog / digital conversion unit that converts the analog signal into a digital signal and outputs the digital signal to the control unit Input section,
The in-vehicle audio reproduction system according to claim 1, further comprising: The input unit is
4. The in-vehicle audio reproduction system according to claim 3, further comprising an external input for capturing an analog audio signal reproduced and output at the other seat. An output selection unit for switching the output destination of the digital signal output from the control unit based on a passenger's instruction, and a digital / analog conversion unit for converting the digital signal into an analog signal and outputting the analog signal to a connected speaker or headphone An output unit having
The in-vehicle audio reproduction system according to claim 1, further comprising: An in-vehicle audio reproduction system capable of reproducing audio independently at front and rear seats in a vehicle interior space,
An input unit that captures an audio signal generated and output by an audio input source at one seat and an audio signal reproduced and output at the other seat as an external input;
A control unit that sequentially monitors the audio signal captured via the input unit at the front and rear seats, and sequentially controls and reproduces the volume and frequency characteristics at the other seat according to the volume and frequency characteristics at one seat;
An output unit that outputs an audio signal output by the control unit by switching an output destination based on a passenger's instruction;
An in-vehicle audio reproduction system comprising:

Images