JP4928967B2 - AUDIO DEVICE, ITS METHOD, PROGRAM, AND RECORDING MEDIUM - Google Patents

Description

The present invention relates to an acoustic device, a sound reproduction processing method used in the acoustic device, a sound reproduction processing program for executing the sound reproduction processing method, and a recording medium on which the sound reproduction processing program is recorded.

  In recent years, with the widespread use of CD (Compact Disk), DVD (Digital Versatile Disk) and the like, multi-surround sound devices have been developed. As a result, it is possible to enjoy surround sound full of realism not only in the home space but also in the vehicle space.

  By the way, the installation environment of an acoustic device is various, and the case where the speaker which outputs an audio | voice cannot be arrange | positioned in the position which has the symmetry (henceforth only "symmetry") from the viewpoint of a multi-surround system often occurs. In particular, when a multi-surround sound device is installed in a vehicle, the restriction on the seating position as a listening position and the restriction on the position where the speaker can be placed are strict, and each speaker and listening position (for example, driving) The positional relationship with the (seat) cannot have symmetry in terms of the multi-surround method. If the positional relationship between each speaker and the listening position does not have symmetry from the viewpoint of the multi-surround method, the sound localization and the sense of presence at the listening position are deteriorated.

  For this reason, when the positional relationship between each speaker and the listening position in the acoustic device does not have symmetry, it is necessary to correct the sound propagation characteristics from each speaker to the listening position. As this correction method, there is a time alignment correction in which a signal output from a speaker is delayed in advance so that sound from each speaker reaches the listening position at the same time.

  As a method of setting the delay time in this time alignment correction, a test audio signal with a fixed constant frequency is driven to the speaker, and the time when this test audio signal is maximized and the sound pressure of acoustic radiation at the listening position are maximized. There is one that calculates a time difference from a certain time and sets a delay time for an output sound signal input to a speaker based on this time difference (see Patent Document 1 and the like: hereinafter referred to as “conventional example”). .

JP-A-7-87598

  The above-described conventional time alignment correction generates a test audio signal having a fixed constant frequency in any audio output system having a plurality of speakers. For this reason, when the frequency of the test audio signal is not appropriate for a certain speaker, it is difficult to obtain a good test audio signal level at the listening position and a noise level (SN ratio) due to noise or the like. If a good signal-to-noise ratio cannot be obtained, the measurement error becomes large and the accuracy of time alignment correction cannot be ensured.

  For example, in a conventional example, an appropriate time alignment is suitable for a two-way speaker including two speakers, a high sound reproduction speaker (hereinafter also referred to as “tweeter”) and a low sound reproduction speaker (hereinafter also referred to as “woofer”). The correction may not be performed. That is, since the frequency characteristics of the two speakers are greatly different, for example, if the frequency of the test audio signal is set too low in accordance with the woofer, the acoustic radiation pressure of the tweeter is hardly obtained. End up. Conversely, if the test audio signal frequency is set too high in accordance with the tweeter, the acoustic radiation pressure of the woofer will hardly be obtained, and a good test audio signal level and noise level will be obtained. It becomes impossible to obtain the ratio (SN ratio). Furthermore, with regard to the tweeter, when a low-frequency signal that cannot be reproduced is input, the device may be damaged.

  For this reason, there is an urgent need for a technique that can accurately perform time alignment correction in any audio output system having a plurality of speakers. Meeting this requirement is one of the problems to be solved by the present invention.

  The present invention has been made in view of the above circumstances, and provides a new acoustic device and sound reproduction processing method capable of correcting appropriate sound propagation characteristics when appreciating music. With the goal.

Invention of claim 1, an acoustic device for outputting sound toward a plurality of speakers to the sound field space, a sound collecting means for collecting sound at a predetermined sound collection position of the sound field space; the For each of the plurality of speakers, the characteristic measurement sound of a plurality of frequencies within a predetermined frequency range is sequentially output, and the sound output for each of the plurality of speakers is performed based on the sound collection result of the characteristic measurement sound by the sound collecting means. An estimation means for estimating a frequency characteristic of the sound ; and for each of the plurality of speakers, a sound waveform for synchronization suitable for measuring the arrival time of the output sound to the sound collection means is calculated based on an estimation result by the estimation means calculating means and for, from each of the plurality of speakers, causes sequentially output the test sound of the corresponding synchronizing audio waveform, the test sound by the sound collecting means Based on the sound results, the adjustment means for adjusting the audio output timing between a plurality of speakers each other; wherein the estimation means, for each of the plurality of speakers, corresponding to the sweep signal for frequency changes in the audible range the Outputting a characteristic measurement voice, estimating a lower limit frequency and an upper limit frequency of a continuous frequency section in which sound pressure characteristics are good based on a sound collection result of the characteristic measurement voice, and the calculating means includes the plurality of speakers. For each of the above, the synchronization voice is subjected to inverse discrete Fourier transform of the frequency distribution of the sound pressure level in which the interval between the lower limit frequency and the upper limit frequency estimated by the estimation means is a predetermined finite constant value and the other interval is zero. An acoustic device characterized by calculating a waveform .

The invention according to claim 5 is a sound reproduction processing method used in an acoustic device including sound collection means for collecting sound at a predetermined sound collection position in a sound field space, wherein a predetermined value is obtained for each of the plurality of speakers. Estimation of estimating frequency characteristics related to sound output for each of the plurality of speakers based on the sound collection result of the characteristic measurement sound by the sound collecting means in sequence. A step of calculating, for each of a plurality of speakers, a sound waveform for synchronization suitable for measuring the arrival time of the output sound to the sound collecting means based on the estimation result in the estimating step; from each of the speakers, with to output test sound of the corresponding synchronizing speech waveform successively, based on the collected results of the test sound by the sound collecting means An adjusting step of adjusting the audio output timing among the plurality of speakers each other; wherein the estimated step, for each of the plurality of speakers, to output the characteristic measurement sounds corresponding to the sweep signal for frequency changes in the audible range The lower limit frequency and the upper limit frequency of a continuous frequency section in which sound pressure characteristics are good are estimated based on the sound collection result of the characteristic measurement sound. In the calculation step, the estimation is performed for each of the plurality of speakers. Performing the inverse discrete Fourier transform of the frequency distribution of the sound pressure level in which the interval between the lower limit frequency and the upper limit frequency determined in the process is a predetermined finite constant value and the other intervals are zero, and calculating the sound waveform for synchronization A sound reproduction processing method characterized by the above.

A sixth aspect of the present invention is a sound reproduction processing program that causes a calculation means to execute the sound reproduction processing method according to the fifth aspect.

A seventh aspect of the present invention is a recording medium on which the sound reproduction processing program according to the sixth aspect of the present invention is recorded so as to be readable by the calculation means.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment]
First, a first embodiment of the present invention will be described with reference to FIGS. In the first embodiment, an acoustic device mounted on a vehicle CR (see FIG. 2) will be described as an example.
<Configuration>
FIG. 1 is a block diagram illustrating a schematic configuration of an acoustic device 100A according to the first embodiment. As shown in FIG. 1, a control unit 110A and a drive unit 120 are provided.

The acoustic device 100A includes a sound output unit 130 _1, a sound output unit 130 _2, a sound output unit 130 _3, a sound output unit 130 _4, a sound output unit 130 _5, a sound output unit 130 _6, sound an output unit 130 _7, and a sound output unit 130 _8.

Here, the sound output unit 130 ₁ has a left speaker tweeter 131 ₁ , and the sound output unit 130 ₂ has a left speaker woofer 131 ₂ . Further, the sound output unit 130 ₃ has a tweeter 131 ₃ right speaker, the sound output unit 130 ₄ has a woofer 131 ₄ right speaker.

Further, a sound output unit 130 ₅ has a tweeter 131 ₅ surround left speaker, the sound output unit 130 ₆ has a woofer 131 ₆ surround left speaker. Further, a sound output unit 130 ₇ includes a tweeter 131 ₇ surround right speakers, the sound output unit 130 ₈ has a woofer 131 ₈ surround right speaker.

  Furthermore, the acoustic device 100A includes a sound collection unit 140 as sound collection means, a display unit 150, and an operation input unit 160 as operation input means.

  The elements 120 to 160 other than the control unit 110A are connected to the control unit 110A.

  The control unit 110A performs overall control of the entire sound device 100A. Details of the control unit 110A will be described later.

  When the drive unit 120 receives a sound content playback command from the control unit 110A in a state where the compact disc CD on which the sound content is recorded is inserted, the drive unit 120 reads the sound content for which the playback command has been issued from the compact disc CD. The result of reading out the sound content is sent to the control unit 110A as content data CTD which is an audio signal.

Each of the sound output units 130 _{1 to} 130 ₈ includes (i) a DA converter (Digital to Analog Converter) that converts digital audio data received from the control unit 110A into an analog signal, and (ii) And an amplifier for amplifying the analog signal output from the DA converter. These sound output units 130 _{1 to} 130 ₈ reproduce and output test audio signals, music pieces, and the like under the control of the control unit 110A.

In the present embodiment, as the sound output unit 130 tweeter 131 ₁ of ₁ left speaker and sound output unit 130 woofer 131 ₂ of the _second left speaker shown in FIG. 2, arranged in front door housing the passenger side Has been. These left speakers 131 ₁ and 131 ₂ are arranged so as to face the passenger seat side.

Woofer 131 ₄ right speaker of the sound output unit 130 tweeter 131 _{3 3} right speaker and the sound output unit 130 ₄ is disposed in front door housing of the driver's seat side. These light speakers 131 ₃ and 13 ₄ are arranged so as to face the driver's seat side.

Woofer 131 ₆ surround left speaker tweeters 131 ₅ and the sound output unit 130 ₆ surround left speaker of the sound output unit 130 ₅ is arranged in the housing of the front passenger's seat side rear. These surround left speakers 131 ₅ and 13 ₁₆ are disposed so as to face the rear seats on the passenger seat side.

Woofer 131 ₈ surround right speakers of the sound output unit 130 tweeter 131 ₇ surround right speaker ₇ and a sound output unit 130 ₈ is placed in the housing of the driver's side rear. These surround right speakers 131 _7, 131 _8, are arranged so as to face the rear seat on the driver side.

  Returning to FIG. 1, the sound collection unit 140 includes (i) a microphone that collects ambient sounds and generates an electrical analog audio signal, (ii) an amplifier that amplifies the analog audio signal output from the microphone, and (iii) An AD converter (Analog to Digital Converter) that converts an amplified analog audio signal into a digital audio signal is provided. Here, the microphone is disposed at at least one predetermined position in the sound field space ASP. The sound collection result data AAD by the sound collection unit 140 is reported to the control unit 110A.

  The display unit 150 is based on (i) a display device 151 such as a liquid crystal display panel, an organic EL (Electro Luminescence) panel, or a PDP (Plasma Display Panel), and (ii) display control data IMD sent from the control unit 110A. The display unit 150 includes a display controller such as a graphic renderer for controlling the entire display unit 150, and (iii) a display image memory for storing display image data. The display unit 150 displays operation guidance information and the like under the control of the control unit 110A.

  The operation input unit 160 includes a key unit provided in the main body of the acoustic device 100A, or a remote input device including the key unit. Here, a touch panel provided on the display device 151 of the display unit 150 can be used as the key part provided on the main body. In addition, it can replace with the structure which has a key part, and the structure which inputs voice can also be employ | adopted.

  When the user operates the operation input unit 160, the operation content of the acoustic device 100A is set. For example, the user performs setting of frequency characteristics of each speaker, reproduction of sound content, and the like using the operation input unit 160. Such input content is sent as operation input data IPD from the operation input unit 160 to the control unit 110A.

The control unit 110A controls the operation of two sound output modes, ie, “playback mode” and “delay time setting mode” in the audio device 100A. Here, the “playback mode” is a mode in which sound content is read out from the compact disc CD and the audio signal is played back. The “delay time setting mode” is a mode in which a test audio signal is generated and measured, and the speaker 130 _j (j = 1 to 8) is a mode for setting a delay time corresponding to each of the speakers 130 _{j in} order to perform time alignment correction of the audio output timing from each.

As shown in FIG. 3, the control unit 110A includes a control processing unit 111A as delay control means . In addition, the control unit 110A includes a channel signal processing unit 112, a signal delay unit 113 as a delay unit, an output signal selection unit 114, and a synchronous measurement signal generation unit 115A as a calculation unit .

  The control processing unit 111A analyzes the operation input data IPD received from the operation input unit 160, and determines which sound output mode of the “delay time setting mode” of the “playback mode” is set to the sound device 100A. . Based on the analysis result, the control processing unit 111A instructs the channel signal processing unit 112, the signal delay unit 113, the output signal selection unit 114, and the synchronous measurement signal generation unit 115A constituting the control unit 110A. Send.

  Here, the commands sent from the control processing unit 111A include a content reproduction control command CPC for the channel signal processing unit 112, a delay control command DLC for the signal delay unit 113, and output signal data for the output signal selection unit 114. There are a selection command ODS and a synchronous measurement signal generation control command SGC to the synchronous measurement signal generator 115A. These instructions will be described later.

In addition, the control processing unit 111A receives a report of the sound collection result data AAD by the sound collection unit 140 that has collected the test sound signal in the “delay time setting mode”. Then, the control processing unit 111A analyzes the collected result data AAD, calculates the delay time DL ₁ through DL ₈ of output sound signals inputted to the speaker 131 _{1-131 8} (see FIG. 4). Then, the calculation result is sent to the signal delay unit 113 together with the delay control command DLC.

  In addition, the control processing unit 111A displays information such as the waveform of the test audio signal used for time alignment correction, the frequency characteristics of each speaker, the set delay time for the output sound signal input to each speaker as display data IMD. 150. As a result, these pieces of information are displayed on the display device 151 of the display unit 150.

  The control processing unit 111A includes a timer circuit and a storage unit (both not shown) for performing time alignment correction.

When the operation input unit 160 reports that the content to be played back including the sound content has been input, the channel signal processing unit 112 should play back the content according to the content playback control command CPC from the control processing unit 111A. The content data CTD corresponding to the content is read from the drive unit 120 and expanded to generate a digital sound data signal. Subsequently, the channel signal processing unit 112 analyzes the generated digital sound data signal, and converts the digital sound data signal to each of the sound output units 130 _{1 to} 130 ₈ described above according to the channel designation information included in the digital sound data signal. Separated to be supplied to. Thus the sound output unit 130 ₁ to 130 of eight is separated data signal every ₈ sound output isolation data signal LOD ₁ ~LOD ₈ is outputted to the signal delay unit 113.

  The content reproduction control command CPC described above is issued from the control processing unit 111A to the channel signal processing unit 112 when the audio device 100A is in the “reproduction mode” described above.

Signal delay unit 113, as shown in FIG. 4, corresponding to the eight sound output unit 130 ₁ to 130 _8, has eight delay units 113 ₁ to 113 _8. Each delay unit 113 _i (i = 1, 2,..., 8) outputs a signal LOD _i that has been separated by the channel signal processing unit 112 for a time DL _{i in} accordance with each signal delay control command DLC _{i from} the control processing unit 111A. Delay. The signal delayed by the delay device 113 _i is output to the output signal selection unit 114 as the output sound delay correction data signal COD _i .

Output signal selecting section 114, as shown in FIG. 5, corresponding to the eight sound output unit 130 ₁ to 130 _8, has eight switch elements 114 ₁ to 114 _8. Each of the switch elements 114 _i has terminals 114 _iA , 114 _iB , and 114 _iC , respectively. Here, the terminal 114 _iA is a terminal connected to the signal delay unit 113, and the terminal 114 _iB is a terminal connected to the synchronous measurement signal generation unit 115A. The terminal 114 _iC is a terminal connected to the sound output unit 130 _i . The operation of each switch element 114 _i is performed according to each output signal selection command ODS _i by the control processing unit 111A.

When the synchronous measurement signal generation unit 115A receives the synchronous measurement signal generation control command SGC from the control processing unit 111A in the “delay time setting mode”, the test audio signal corresponding to the frequency characteristics of the speakers 131 _{1 to} 13 ₁₈ is received. SGD is generated. In generating the test audio signal SGD, a discrete Fourier transform, that is, a Z transform technique is used in the present embodiment.

Generally, as the frequency characteristics of the speaker 131 _j (j = 1 to 8), the sound pressure X _j (in FIG. 6) of the individual speaker 131 _{j at} each of the frequencies f _{j, m} (m = 1 to M) as shown in FIG. When f _{j, m} ) is obtained, a test speech waveform x _j (t) (t: time) suitable for the speaker 131 _j is calculated by performing Z ⁻¹ conversion expressed by the following equation (1). be able to. The test speech waveform x _j (t) calculated in this way becomes a waveform as shown in FIG.

Ｃ：定数
Ｎ：サンプリング数（奇数）
Ｔ_S：サンプリング周期

C: Constant
N: Number of sampling (odd number)
T _S : Sampling cycle

Here, the constant C, the sampling number N, and the sampling period T _S are determined in advance in the synchronous measurement signal generator 115A.

In this embodiment, the sound pressure characteristic of the speaker obtained by the user referring to the speaker catalog or the like by the key operation of the operation input unit 160 prior to the operation in the “delay time setting mode” is good. Only information corresponding to the minimum frequency value f _{min, j} and the maximum frequency value f _{max, j} in the frequency range is input. That is, in the present embodiment, it is assumed that each of the speakers 131 _j can be approximated with an accuracy within an allowable range by the frequency characteristics as shown in FIG.

The minimum frequency value f _{min, j} and the maximum frequency value f _{max, j} input as described above are registered in the control processing unit 111A. The frequency characteristic information is sent from the control processing unit 111A to the synchronous measurement signal generation unit 115A as a parameter of the synchronous measurement signal generation control command SGC in the “delay time setting mode”. The synchronous measurement signal generator 115A that has received the synchronous measurement signal generation control command SGC performs a test according to the following equation (2) with f _{min, j} = f _{j, 1} and f _{max, j} = f _{j, 2.} An audio signal x _j (t) is calculated.

<Operation>
The operation of the acoustic device 100A configured as described above will be described mainly focusing on time alignment correction in the “delay time setting mode”.

First, when the user selects the “delay time setting mode” by input to the operation input unit 160, in step S11 of FIG. 9, the control unit 110A (more specifically, the control processing unit 111A) of the acoustic device 100A The speaker 1311 is selected as the _first speaker for setting the delay time for time alignment correction.

In step S11, when the control processing unit 111A selects one speaker, the control processing unit 111A sends an output signal data selection command ODS to the output signal selection unit 114 (see FIG. 3). Although the output signal data selection command ODS includes individual commands ODS _{1 to} ODS ₈ (see FIG. 5), when only the speaker 131 ₁ is selected, the individual command ODS ₁ is connected to the synchronous measurement signal generator 115A. This is a command for connecting the sound output unit 130 ₁ , and in accordance with this command, the terminal 114 _1B and the terminal 114 _{1C of} the switch element 114 ₁ become conductive. The other individual commands ODS _{2 to} ODS ₈ are commands for not connecting the synchronous measurement signal generator 115A and the sound output units 130 _{2 to} 130 ₈ , and settings according to these commands are set in the switch elements 114 _{2 to} 114 ₈ . Done.

Subsequently, in step S12, the control processing unit 111A uses the frequency characteristic information of the speaker 131 ₁ registered therein as a parameter to generate a synchronous measurement signal generation control command SGC indicating that a test audio signal for the speaker 131 ₁ should be generated. Is sent to the synchronous measurement signal generator 115A. Upon receiving the synchronous measurement signal generation control command SGC, the synchronous measurement signal generation unit 115A performs the calculation of the above-described equation (2) according to the synchronous measurement signal generation control command SGC, and generates the test audio signal SGD.

Synchronous measurement signal generator test sound signal SGD which 115A is generated via the output signal selector 114 to switch configuration described above is being performed, it is supplied to the sound output unit 130 _1. As a result, in step S13, the speaker 131 _1, test sound for the speaker 131 ₁ are outputted. When the sound pressure of the test voice reaches the maximum, the time of the timer circuit built in the control processing unit 111A is set to zero and started.

Next, in step S14, a test sound output from the speaker 131 _1, the listening position (for example, driver's seat P1) is collected by the microphone of the sound collecting unit 140 installed in. The sound collection result is sent to the control processing unit 111A as sound collection result data AAD. Then, when the sound pressure of the test sound collected by the microphone becomes maximum, the timer circuit of the control processing unit 111A started in step S13 is stopped.

Next, in step S15, stores the timer value when to stop the timer circuit of the control processing unit 111A in the storage unit to the control processing unit 111A as the propagation time until the sound collection position of the output sound regarding the speaker 131 _1.

The processing from step S12 to step S15 is performed for a predetermined number of times. And let the average value of the measured propagation time be the average propagation time AD ₁ regarding the speaker 131 ₁ . This average propagation time AD ₁ is stored in the storage unit of the control processing unit 111A.

  In order to secure the measurement accuracy of the propagation time, only good sound collection result data AAD is used for calculating the average propagation time. Here, good sound collection result data AAD means that the maximum value a of the radiation pressure from the speaker is sufficiently larger than the noise level b at the listening position, as shown in FIG. Here, the noise includes white noise, noise that has entered from other spaces, and the like.

Subsequently, in step S16, it is determined whether or not the average delay amount has been obtained for all of the speakers 131 _{1 to} 13 ₁₈ .

  At this stage, since the result of the determination in step S16 is negative (step S16: N), the process proceeds to step S17.

In step S17, a second speaker for implementing time alignment correction, selects the speaker 131 _2.

After selecting the speaker 131 ₂ performs the processing from step S12 described above to step S15.

When the process from step S12 to step S15 is completed for all of the speakers 131 _{1-131 8,} the result of the judgment in step S16 is affirmative: Since (step S16 Y), the process proceeds to step S18.

In this step S18, using the average propagation times AD _{1 to} AD ₈ of the speakers 131 _{1 to} 13 ₈ stored in the storage unit of the control processing unit 111A, the control processing unit 111A uses the average propagation times AD _{1 to} AD ₈ to correct each speaker 131 _1. the delay time for delaying the output sound signal to be input to to 131 ₈ calculates the DL ₁ through DL _8.

The delay times DL _{1 to} DL ₈ are calculated as follows. First, among the above average propagation times AD _{1 to} AD ₈ , the largest one is selected as the maximum average propagation time AD _max . Then, on the basis of the maximum average propagation time AD _max , a time corresponding to the difference between AD _max and the average propagation time AD _{1 to} AD _{8 of} each speaker is calculated, and this is set as the delay time DL _{1 to} DL ₈ . . Therefore, the delay time DL _i of the speaker 131 _i is given by calculating the (AD _max -AD _i).

The delay times DL _{1 to} DL ₈ calculated by the control processing unit 111A in this way are sent to the signal delay unit 113 together with the delay control command DLC.

  Next, the operation of the “reproduction mode” for reproducing the sound content of the compact disc CD after setting the delay time for time alignment correction in the “delay time setting mode” will be described.

When the user designates “reproduction mode” by input to the operation input unit 160, the control processing unit 111A sends an output signal data selection command ODS indicating that it is “reproduction mode” to the output signal selection unit 114. (See FIG. 3). Here, although the output signal data selection command ODS includes individual commands ODS _{1 to} ODS ₈ (see FIG. 5), in the “reproduction mode”, the signal delay unit 113 and all the sound output units 130 _{1 are included.} 130 ₈ and in response to each individual command ODS _i issued in order to connect, in the output signal selecting section 114, thereby turning on the terminal 114 _iA and the terminal 114 _iC of each switch element 114 _i.

When the “reproduction mode” is set, the control processing unit 111A sends a content reproduction control command CPC to the channel signal processing unit 112. The channel signal processing unit 112 reads the content data CTD from the drive unit 120 in accordance with the content reproduction control command CPC, and generates a digital sound data signal. Then, the channel signal processing unit 112 analyzes the digital sound data signal and separates the digital sound data signal so as to be supplied to each of the sound output units 130 _{1 to} 130 ₈ according to channel designation information or the like. The sound output separated data signals LOD _{1 to} LOD ₈ thus separated for each of the sound output units 130 _{1 to} 130 ₈ are output toward the signal delay unit 113.

Signal delay unit 113, the control according to the processing unit 111A signal delay control command DLC by "delay time setting mode" delay units 113 ₁ to 113 ₈ in the set delay time DL ₁ through DL ₈ only sound output isolation data when the Delay signal LOD _i . The output sound delay correction data signals COD _{1 to} COD ₈ delayed for each of the sound output units 130 _{1 to} 130 ₈ in this way are output toward the output signal selection unit 114.

As described above, when the “reproduction mode” is set, the signal delay unit 113 and all the sound output units 130 _{1 to} 130 ₈ are connected in the output signal selection unit 114. Accordingly, the output sound is input to the output signal selecting section 114 delay correction data signal COD ₁ ~COD ₈ as a sound output data signal AOD ₁ ~AOD _8, toward the sound output unit 130 ₁ to 130 ₈ corresponding to each Is output. As a result, sounds based on the sound output data signals AOD _{1 to} AOD ₈ are output from the speakers 131 _{1 to} 13 _{18 of} the sound output units 130 _{1 to} 130 ₈ .

As described above, the acoustic device 100A of the first embodiment, generates and outputs a test audio signal according to the frequency characteristics of the speakers 131 _{1-131 8,} test sound signal to a predetermined pickup position Measure the arrival time. Then, based on the measurement result, time alignment correction is performed. For this reason, it is possible to accurately measure the arrival time of the test audio signal at a predetermined sound collection position, so that the sound localization and realism at the listening position can be improved when listening to music. Can do.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to other drawings as appropriate while mainly referring to FIGS. The second embodiment will also be described by exemplifying an acoustic device mounted on the vehicle CR (see FIG. 2), similarly to the first embodiment described above.

<Configuration>
FIG. 11 is a block diagram illustrating a schematic configuration of the acoustic device 100B according to the second embodiment. As shown in FIG. 11, the acoustic device 100B is different from the acoustic device 100A according to the first embodiment only in that a control unit 110B is provided instead of the control unit 110A. And as FIG. 12 shows, the control unit 110B is equipped with the control processing part 111B which functions also as an estimation means instead of the control processing part 111A compared with the control unit 110A according to the first embodiment, The difference is that a measurement signal generator 115B is provided instead of the synchronous measurement signal generator 115A.

In addition to the two sound output modes of the “reproduction mode” and the “delay time setting mode” of the first embodiment, each of the speakers 131 ₁ to 131 B connected to the acoustic device 100B is included in the acoustic device 100B of the second embodiment. 131 ₈ measures the frequency characteristic of the "characteristic measurement mode" exists.

  The control processing unit 111B analyzes the operation input data IPD received from the operation input unit 160, and based on the analysis result, the channel signal processing unit 112, the signal delay unit 113, and the output signal selection unit 114 that constitute the control unit 110B. A command is sent to each of the measurement signal generators 115B.

  Among these, the commands sent to the channel signal processing unit 112, the signal delay unit 113, and the output signal selection unit 114 are the same as those of the control processing unit 111A of the first embodiment. On the other hand, regarding the command that the control processing unit 111B sends to the measurement signal generation unit 115B, unlike the control processing unit 111A, the synchronous measurement signal generation control command SGC, the characteristic measurement signal generation control command FCC, the signal There are three types of selection commands SGS.

  The contents of the synchronous measurement signal generation control command SGC are the same as in the first embodiment. Details of the characteristic measurement signal generation control command FCC and the signal selection command SGS will be described later.

  Other functions other than those described above, such as the control processing unit 111B including a timer circuit and a storage unit, are the same as those of the control processing unit 111A of the first embodiment.

As illustrated in FIG. 13, the measurement signal generation unit 115B includes a synchronous measurement signal generation unit 115A, a characteristic measurement signal generation unit 116, and a signal selection unit 117.

The characteristic measurement signal generation unit 116 is an element that generates the characteristic measurement signal FCD according to the characteristic measurement signal generation control command FCC from the control processing unit 111B in the “characteristic measurement mode”. Here, the characteristic measurement signal FCD is a signal for measuring the frequency characteristics of the speakers 131 _{1 to} 13 ₁₈ connected to the acoustic device 100B. The signal for measuring the frequency characteristic of the speaker is a sine wave and is a swept signal that varies from 20 Hz to 20 kHz, which is the audible range.

  The signal selection unit 117 generates a test audio signal SGD generated by the synchronous measurement signal generation unit 115A and a characteristic measurement signal FCD generated by the characteristic measurement signal generation unit 116 in accordance with the signal selection command SGS from the control processing unit 111B. Select either one. In the “delay time setting mode”, the test audio signal SGD is selected, and in the “characteristic measurement mode”, the characteristic measurement signal FCD is selected. Then, one of the selected signals is output toward the output signal selection unit 114.

<Operation>
The operation of the acoustic device 100B configured as described above will be described mainly focusing on the measurement operation of the frequency characteristic of the speaker in the above-described “characteristic measurement mode”.

First, when the user designates the “characteristic measurement mode” by input to the operation input unit 160, the control processing unit 111 </ b> B outputs to the output signal selection unit 114 the output signal data indicating the “characteristic measurement mode”. A selection command ODS is sent (see FIG. 12). Similar to the first embodiment, the output signal data selection command ODS includes individual commands ODS _{1 to} ODS ₈ (see FIG. 5). When the “characteristic measurement mode” is designated, the individual command ODS ₁ is a command for connecting the measurement signal generator 115B and the sound output unit 130 ₁ , and the terminal 114 _{1B of the} switch element 114 ₁ according to this command. And the terminal 114 _1C become conductive. The other individual commands ODS _{2 to} ODS ₈ are commands for preventing the measurement signal generator 115B and the sound output units 130 _{2 to} 130 ₈ from being connected, and the settings according to the commands are switch elements 114 _{2 to} 114 _8. Done in

  When the “characteristic measurement mode” is designated, the control processing unit 111B sends a signal selection command SGS to the signal selection unit 117 indicating that the characteristic measurement signal FCD should be selected (see FIG. 13). As a result, in the “characteristic measurement mode”, the characteristic measurement signal FCD generated by the characteristic measurement signal generator 116 is sent from the measurement signal generator 115B to the output signal selector 114 as the measurement signal MSD.

  Subsequently, the control processing unit 111B sends a characteristic measurement signal generation control command FCC to the characteristic measurement signal generation unit 116 to request generation of the characteristic measurement signal FCD.

Characteristic measurement signal generation unit 116 which receives the characteristic measurement signal generation control command FCC generates a characteristic measurement signal FCD for measuring the frequency characteristic of the speaker 131 ₁ is tweeter. In the second embodiment, as the characteristic measurement signal FCD, a sine wave sweep signal in which the frequency f _{1, m} sequentially changes in the audible range of 20 Hz to 20 kHz is employed. Note that the frequency range of the characteristic measurement signal FCD generated by the characteristic measurement signal generator 116 can be arbitrarily set by the user.

Characteristic measurement signal generating section 116 characteristic measurement signal FCD generated by, after having passed through the signal selection section 117 and the output signal selecting section 114 sequentially supplied to the sound output unit 130 _1. As a result, audio based on the characteristic measurement signal FCD is output from the speaker 131 _1.

Sound output from the speaker 131 ₁ is collected by the microphone of the installed collected unit 140 to the listening position. The sound pressure X ₁ (f _{1, m} ) at the frequency f _{1, m as} the sound collection result is sent to the control processing unit 111B as sound collection result data AAD and stored in the storage unit.

The control processing unit 111B repeats the above measurement a predetermined number of times, and uses the frequency f _{1, m} and the sound pressure X ₁ (f _{1, m} ) at the frequency f _{1, m} as the sampling number N and the sampling period T _S. At the same time, it is registered in the storage unit as frequency characteristic information. Examples of the frequency characteristics of the speaker 131 ₁ thus specified are shown by solid lines in FIGS. 14 (A) and 14 (B).

Then, under the control of the control processing unit 111B, the processing of the measurement and registration of the frequency characteristic of the audio output for the speaker 131 ₂ is woofers performed. Control processing unit 111B, first, towards the output signal selecting section 114, and sends an output signal data selection instruction ODS for connecting measuring signal generating portion 115B and the sound output unit 130 _2. Individual command ODS ₂ in this case is a command for connecting a measuring signal generating portion 115B and the sound output unit 130 _2, according to the command, the terminal 114 _2B of the switching element 114 ₂ and the terminal 114 _2C and the conductive state Become. The other individual commands ODS ₁ , ODS _{3 to} ODS ₈ are commands for not connecting the measurement signal generator 115B and the sound output units 130 ₁ , 130 _{3 to} 130 ₈ , and the settings according to these commands are switches. performed in element 114 _1, 114 _{3-114 8.}

Next, the control processing unit 111B sends a characteristic measurement signal generation control command FCC to the characteristic measurement signal generation unit 116. Characteristic measurement signal generation unit 116 which receives the characteristic measurement signal generation control command FCC generates a characteristic measurement signal FCD for measuring the frequency characteristic of the speaker 131 _2. Characteristic measurement signal generating section 116 generates characteristic measurement signal FCD, after having passed through the signal selection section 117 and the output signal selecting section 114 sequentially supplied to the sound output unit 130 _2.

Sound output from the speaker 131 ₂ is collected by the microphone of the sound collection unit 140. The sound pressure X ₂ (f _{2, m} ) at the frequency f _{2, m as} the sound collection result is sent to the control processing unit 111B as sound collection result data AAD and stored in the storage unit. The control processing unit 111B repeats the above measurement a predetermined number of times, and uses the frequency f _{2, m} and the sound pressure X ₂ (f _{2, m} ) at the frequency f _{2, m} as the sampling number N and the sampling period T _S. At the same time, it is registered in the storage unit as frequency characteristic information. Thus examples of the identified speaker 131 _second frequency characteristic, FIG. 14 (A), the shown by the two-dot chain line in (C).

Hereinafter, sequentially, similarly to the measurement of the frequency characteristic of the speaker 131 _1, 131 ₂ above, measurement and registration process in the frequency characteristic of the audio output for the loudspeaker 130 _{3-130 8,} under the control of the control unit 111B Done in

Measurement is completed in the frequency characteristic of the speaker 131 _{1-131 2} by "characteristic measurement mode" continues, when the user specifies the "delay time setting mode", the control unit 111B, first, the signal selector 117 A signal selection command SGS for selecting the test audio signal SGD is sent to Next, the control processing unit 111B sends a synchronous measurement signal generation control command SGC toward the synchronous measurement signal generation unit 115A.

The synchronous measurement signal generator 115A performs the calculation of the above-described equation (1) based on the detailed frequency characteristic information of each of the speakers 131 _{1 to} 131 ₂ obtained by the measurement in the “characteristic measurement mode”, and performs a test. An audio signal SGD is generated. The delay time setting process after the test audio signal SGD is generated is the same as the process in the first embodiment.

  Further, when the time alignment correction by the “delay time setting mode” is completed and the user designates the “reproduction mode”, the audio content recorded on the CD is reproduced as in the case of the first embodiment.

As described above, the acoustic device 100B of the second embodiment, a detailed frequency characteristic of the speaker 131 _{1-131 8} measures the output of the frequency characteristic information by generating a test sound signal based on Then, the arrival time of the test sound signal at a predetermined sound collection position is measured. Then, based on the measurement result, time alignment correction is performed. For this reason, even when the sound pressure characteristics of the speaker cannot be known due to loss of the speaker catalog etc., the arrival time of the test audio signal to the predetermined sound collection position can be accurately measured, and the music It is possible to improve the sense of sound localization and presence at the listening position when appreciating the sound.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and various modifications are possible.

  For example, in the first and second embodiments described above, the drive unit 120 is a CD drive unit, but may be a fixed disk or DVD drive unit. Furthermore, a broadcast wave receiving circuit such as a radio broadcast or a terrestrial digital television broadcast can be used.

  In the first and second embodiments, the 2-way speaker system is used. However, a 3-way speaker system may be used, or a 1-way speaker system may be used.

  In the first and second embodiments described above, the eight sound output units are provided. However, the audio signal which is the result of reading the sound content is appropriately separated or mixed, and the number of speakers is seven or less or nine or more. It is also possible to make sound output from.

In the first embodiment, only the values corresponding to the minimum value f _{min, j} and the maximum value f _{max, j} shown in FIG. 8 are used as the frequency characteristic information of each speaker. Information can also be adopted. For example, the sound pressure X _j (f _{min, j} ) and X _j (f _{max, j} ) are input as frequency characteristic information of the speaker 131 _j together with the minimum value f _{min, j} and the maximum value f _{max, j} , and (1 ) Equation may be used to calculate the test speech waveform.

For the speaker 131 _j , three or more frequencies f _{j, m} and sound pressure X _j (f _{j, m} ) at each of the frequencies f _{j, m} are input as frequency characteristic information, and A test speech waveform may be calculated.

Further, after obtaining a frequency characteristic curve for the speaker 131 _j by a predetermined algorithm based on the input frequency characteristic information, the test voice waveform is obtained by the equation (1) using the frequency characteristic curve. You may make it calculate.

  In the second embodiment, a sine wave sweep signal is used as the characteristic measurement signal FCD. However, the frequency characteristic of the speaker is determined by the characteristic measurement signal and its acoustic response, such as pink noise and TSP signal (time stretch signal). Any information can be used.

In the second embodiment, the test sound waveform is calculated by the equation (1) based on the detailed frequency characteristic information of the speaker 131 _j . On the other hand, as shown in FIG. 15, the minimum frequency value f _{min, j} and the maximum frequency value f _{max, j} in the frequency range where the sound pressure characteristic of the speaker 131 _j is good are obtained from an appropriate algorithm or the like ( The test speech waveform may be calculated by the equation 2).

  In the first and second embodiments, the present invention is applied to an acoustic device mounted on a vehicle. However, the present invention is also applied to an acoustic device mounted on a moving body other than the vehicle. The present invention can also be applied to an acoustic device that is not mounted on a moving body.

  Note that some or all of the control units 110A and 110B in the first and second embodiments described above are a central processing unit (CPU), a DSP (Digital Signal Processor), and a read only memory (ROM). ), A computer as a computing means having a random access memory (RAM) and the like, and by executing a program prepared in advance on the computer, part or all of the processing in the above embodiment May be executed. This program is recorded on a computer-readable recording medium such as a hard disk, CD-ROM, or DVD, and is read from the recording medium and executed by the computer. The program may be acquired in a form recorded on a portable recording medium such as a CD-ROM or DVD, or may be acquired in a form of delivery via a network such as the Internet. Also good.

1 is a block diagram schematically showing the configuration of an acoustic device according to a first embodiment of the present invention. It is a figure for demonstrating the arrangement position of the eight speakers of FIG. It is a block diagram for demonstrating the structure of the control unit of FIG. It is a block diagram for demonstrating the structure of the signal delay part of FIG. It is a block diagram for demonstrating the structure of the output signal selection part of FIG. It is a figure of the frequency characteristic for demonstrating the method of Z conversion. 7 is a test voice waveform obtained by performing Z ⁻¹ conversion on the frequency characteristics shown in FIG. 6. It is the figure which modeled the frequency characteristic of the speaker. It is a flowchart for demonstrating time alignment correction. It is a figure for demonstrating the relationship between the radiated sound from a speaker in a listening position, and noise. It is a block diagram which shows roughly the structure of the audio equipment concerning 2nd Embodiment of this invention. It is a block diagram for demonstrating the structure of the control unit of FIG. It is a block diagram for demonstrating the structure of the synchronous measurement signal generation part of FIG. It is a figure for demonstrating the frequency characteristic of a speaker. It is a figure for demonstrating a modification.

Explanation of symbols

100A, 100B ... acoustic device 110A, 110B ... control unit
111A ... Control processing unit ( delay control means )
111B: Control processing unit (estimating means, delay controlling means)
113 ... Signal delay unit (delay means)
115A: Synchronous measurement signal generator (calculation means)
116 ... Characteristic measurement signal generator 120 ... Drive units 130 _{1 to} 130 ₈ ... Sound output units 131 _{1 to} 131 ₈ ... Speakers 140 ... Sound collection units (sound collection means)
160 ... operation input unit (operation input means)

Claims (7)

An acoustic device that outputs sound from a plurality of speakers to a sound field space,
Sound collection means for collecting sound at a predetermined sound collection position in the sound field space;
For each of the plurality of speakers, the characteristic measurement sound of a plurality of frequencies within a predetermined frequency range is sequentially output, and the sound for each of the plurality of speakers is output based on the sound collection result of the characteristic measurement sound by the sound collecting means. An estimation means for estimating a frequency characteristic relating to the output;
Calculating means for calculating a sound waveform for synchronization suitable for measuring the arrival time of the output sound to the sound collecting means based on the estimation result by the estimating means for each of the plurality of speakers;
Each of the plurality of speakers sequentially outputs a corresponding test sound of the synchronization sound waveform, and based on a sound collection result of the test sound by the sound collecting means, a sound output timing between the plurality of speakers. and adjusting means for adjusting; equipped with,
The estimation means is provided for each of the plurality of speakers.
Output the characteristic measurement sound corresponding to the sweep signal whose frequency changes in the audible range,
Based on the sound collection result of the characteristic measurement voice, the lower limit frequency and the upper limit frequency of a continuous frequency section where the sound pressure characteristic is good are estimated,
The calculation means, for each of the plurality of speakers, is an inverse discrete of the frequency distribution of the sound pressure level in which a section between the lower limit frequency and the upper limit frequency estimated by the estimation means is a predetermined finite constant value and the other sections are zero. Performing a Fourier transform to calculate the audio waveform for synchronization;
An acoustic device characterized by that. The adjusting means includes
Delay means for providing a delay for each audio signal derived from audio content and supplied to each of the plurality of speakers;
Delay control means for calculating and setting a delay time for each sound signal in the delay means based on an output time for each test sound and an arrival time for the test sound to the sound collecting means;
The acoustic device according to claim 1, comprising: The acoustic device according to claim 1, wherein the synchronization audio waveform has temporal symmetry with respect to a maximum peak time. The acoustic device according to claim 1 , wherein the acoustic device is mounted on a moving body. A sound reproduction processing method used in an acoustic device including sound collection means for collecting sound at a predetermined sound collection position in a sound field space,
For each of the plurality of speakers, the characteristic measurement sound of a plurality of frequencies within a predetermined frequency range is sequentially output, and the sound for each of the plurality of speakers is output based on the sound collection result of the characteristic measurement sound by the sound collecting means. An estimation step for estimating a frequency characteristic related to the output;
A calculation step of calculating, for each of a plurality of speakers, a synchronization audio waveform suitable for measuring the arrival time of the output audio to the sound collecting means based on the estimation result in the estimation step;
Each of the plurality of speakers sequentially outputs a corresponding test sound of the synchronization sound waveform, and based on a sound collection result of the test sound by the sound collecting means, a sound output timing between the plurality of speakers. comprising a; and adjusting step for adjusting the
In the estimation step, for each of the plurality of speakers,
Output the characteristic measurement sound corresponding to the sweep signal whose frequency changes in the audible range,
Based on the sound collection result of the characteristic measurement voice, the lower limit frequency and the upper limit frequency of a continuous frequency section where the sound pressure characteristic is good are estimated,
In the calculating step, for each of the plurality of speakers, an inverse discrete of the frequency distribution of the sound pressure level in which the interval between the lower limit frequency and the upper limit frequency determined in the estimation step is a predetermined finite constant value and the other intervals are zero. Performing a Fourier transform to calculate the audio waveform for synchronization;
And a sound reproduction processing method. 6. A sound reproduction processing program for causing a calculation means to execute the sound reproduction processing method according to claim 5 . 7. A recording medium on which the sound reproduction processing program according to claim 6 is recorded so as to be readable by an arithmetic means.

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