JP4231817B2 - Acoustic simulation apparatus, acoustic simulation program, and recording medium - Google Patents

Description

  The present invention relates to a technique for simulating sound in a vehicle interior.

Conventionally, when designing acoustics in a room such as a listening room or a concert hall, it is possible to check the acoustic characteristics by predicting the acoustic performance by computer simulation and reproducing the sound field and actually listening to it. A sound environment simulation experience device is known (see, for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 7-168587

  However, the above-described conventional technology is intended for acoustic design of buildings and the like suitable for listening to music, and the noise of an air conditioner blowing sound when the air conditioner is operating and noise such as running noise when the vehicle is running exist. It cannot be used for the acoustic design of the room (vehicle interior).

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an acoustic simulation apparatus, an acoustic simulation program, and a recording medium that can accurately simulate the acoustics of a vehicle interior where noise exists. .

To achieve the above object, the present invention provides a sound simulation apparatus for simulating acoustic cabin of the vehicle, the structure and acoustic properties of the vehicle interior is the sound receiving point from the sound point of the cabin modeled An impulse response calculating means for calculating the first impulse response to be reached , and the second impulse response based on the second impulse response of the acoustic environment that is a reference acoustic environment reproduced in the vehicle interior and ideal as an acoustic environment for viewing the sound. Based on the corrected first impulse response, the sound field correction generating means for generating a reproduced sound signal indicating the reproduced sound at the sound receiving point in the vehicle interior, and the sound field correction generating means and the reproduced sound signal, and a noise adding means for adding noise noise signal of noise generated during running of the vehicle, reproduction Onshin that said noise signal is added Based on, and a sound quality evaluation unit that calculates a characteristic value indicating the quality of the reproduced sound in the sound receiving point, based on the evaluation result of the sound quality evaluation unit, the position or the sound receiving point of the sound emitting point The position is adjustable .

The present invention further includes an acoustic effect adding means for adding an acoustic effect to the reproduced sound signal to which the noise signal is added in the above invention, wherein the sound quality evaluation means is configured to add the acoustic effect after the acoustic effect is added. A characteristic value indicating the sound quality of the reproduced sound at the sound receiving point is calculated based on the reproduced sound signal, and the acoustic effect can be adjusted based on an evaluation result by the sound quality evaluating means .

  Further, the present invention is characterized in that, in the above-mentioned invention, further comprises output means for outputting the same reproduced sound signal as the reproduced sound signal input to the sound quality evaluating means to the sound emitting device.

According to the present invention, in the above invention, a first storage unit that stores a plurality of data of a structure indicating the structure of the vehicle interior, and a second storage unit that stores data of acoustic characteristics of members disposed in the vehicle interior. Modeling means for selecting the structure data and acoustic characteristic data and modeling the vehicle interior; and a sound receiving position setting means for setting the position of the sound receiving point in the modeled vehicle interior; And the position of the sound receiving point can be adjusted by the sound receiving position setting means based on the evaluation result by the sound quality evaluating means .

  Further, the present invention is characterized in that, in the above invention, the system further comprises third storage means for storing a plurality of the second impulse responses for each reference acoustic environment, and reference acoustic environment setting means for selecting the reference acoustic environment. .

  In the invention described above, the sound field correction generation unit corrects the first impulse response so as to approach the second impulse response.

According to the present invention, in the above-described invention, fourth storage means for preliminarily storing driving noise data generated when the vehicle is traveling, and air-conditioner ventilation generated when an air conditioner provided in the vehicle is operating. Fifth storage means for preliminarily storing sound data, and the noise adding means adds the reproduced sound signal to the reproduced sound signal based on the traveling noise data, or the traveling noise data and the air conditioner blowing sound data. A noise signal is added.

  Further, the present invention is the above invention, wherein the acoustic effect adding means includes: loudness, correction of frequency characteristics according to the noise signal, and active noise control for the reproduced sound signal to which the noise signal is added. It is characterized by adding at least one of the acoustic effects.

  Further, the present invention is the above invention, wherein the output means outputs the reproduced sound signal according to the frequency characteristics of the sound emitting device so that the frequency level of the sound reproduced by the sound emitting device is substantially uniform. Characteristic correction means for correcting is provided.

  Further, the present invention is the above invention, wherein the output means includes crosstalk cancellation means for performing correction for the reproduction signal to prevent crosstalk that occurs when sound is reproduced by the sound emitting device. Features.

In the invention described above, the sound field correction generation unit may calculate a reference evaluation sound signal by a convolution operation between the second impulse response and the evaluation sound signal of the M-sequence code, and the corrected second sound signal may be calculated. The reproduced sound signal is generated by a convolution operation of one impulse response and the evaluation sound signal, and the sound quality evaluation means generates a third impulse response based on a cross-correlation function between the evaluation sound signal and the reproduced sound signal. It is calculated as a characteristic value.

  Further, the present invention is characterized in that, in the above-mentioned invention, the sound quality evaluation means calculates a transmission frequency characteristic formed by Fourier transform of the third impulse response as a characteristic evaluation value.

  Further, the present invention is the above invention, wherein the sound quality evaluation means is an objective sound quality evaluation value (Objective Difference Grade) according to a PEAQ (Perceived Evaluation of Audio Quality) method based on the reproduced sound signal and the reference evaluation sound signal. ) As the characteristic value.

  Also, in the present invention according to the above invention, when the evaluation sound signal is an uncompressed music signal, the sound quality evaluation means performs the reproduction based on a cross-correlation between the reproduction sound signal and the reference evaluation sound signal. A signal synchronization between the sound signal and the reference evaluation sound signal is performed, and the objective sound quality evaluation value that is maximum when the signal level of the reference evaluation sound signal is changed is calculated.

In order to achieve the above object, according to the present invention, there is provided an acoustic simulation program for simulating acoustics in a vehicle interior of a vehicle , wherein a computer is used to model a vehicle interior in which the structure and acoustic characteristics of the vehicle interior are modeled. Means for calculating a first impulse response from a sounding point to a sound receiving point, based on a second impulse response of an acoustic environment that is a reference acoustic environment reproduced in the vehicle interior and is ideal as an acoustic environment for viewing sound; Means for correcting a first impulse response, and generating a reproduced sound signal indicating a reproduced sound at a sound receiving point in the vehicle interior based on the corrected first impulse response; a noise signal for the reproduced sound signal; means for adding, and said noise signal based on the additional reproduction sound signal, means for calculating a characteristic value that indicates the quality of the reproduced sound in the sound receiving point Based on the evaluation result of the sound quality evaluation unit, characterized in that to function as a means for enabling adjusting the position or positions of said sound receiving point of the sound emitting point.

  Further, the present invention is a computer-readable recording medium on which the acoustic simulation program is recorded.

  According to the present invention, it is possible to accurately simulate the sound in the passenger compartment where noise exists.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a functional configuration of an acoustic simulation apparatus 1 according to the present embodiment. Note that the acoustic simulation apparatus 1 includes an acoustic simulation according to the present embodiment in a computer (electronic computer) including a control unit such as an MPU, a storage unit such as a hard disk drive, an input unit such as a keyboard, and a display unit such as a display. By executing the program for the above, various functions described below are realized.

  As shown in FIG. 1, the acoustic simulation device 1 is roughly classified into a sound field simulation unit 10, a sound field tuning unit 20, a noise addition unit 30, an acoustic effect addition unit 40, and a sound field reproduction unit 50. The sound quality evaluation unit 60 is provided.

  The sound field simulation unit 10 models the interior of a vehicle to be designed (hereinafter referred to as “vehicle interior”), and calculates the impulse response in the modeled vehicle interior, as shown in FIG. , A member sound database unit 101, a listening position setting unit 102, a vehicle interior modeling unit 103, and a simulation execution unit 104.

  The member sound database unit 101 stores, for example, a database of characteristics (for example, sound absorption coefficient and sound reflection angle) of various members existing in a vehicle interior such as a speaker device, a window glass, and a seat. It has storage means such as a drive. The listening position setting unit 102 sets the listening position (sound receiving point) of the test listener in the passenger compartment. More specifically, the listening position setting unit 102 stores space shape data (frame shape, seat shape and position thereof, speaker shape and position position, etc.) indicating the structure of the passenger compartment, Input means for receiving the input of the listening position of the test listener in the vehicle interior, and when the listening position is input, the listening position and the space shape data are associated with each other and output to the vehicle interior modeling unit 103. The listening position setting unit 102 stores a plurality of different space shape data in advance, and the user can appropriately select these space shape data and design different vehicle interiors. In addition, it is good also as a structure which a user can correct or change those space shape data suitably.

  The vehicle interior modeling unit 103 reads out the acoustic characteristics of various members arranged in the vehicle interior from the member acoustic database unit 101 when the space shape data and listening position in the vehicle interior are input, The vehicle interior is modeled in association with each other and output to the simulation execution unit 104.

  The simulation execution unit 104 simulates the acoustic characteristics between the speaker (sounding point) and the listening position (sound receiving point) in the vehicle interior modeled by the vehicle interior modeling unit 103 and uses the sound field tuning unit 20 as an impulse response. Is output. Specifically, the simulation execution unit 104 is based on a geometric analysis method such as a sound ray method or a virtual image method, a numerical analysis method such as a finite element method or a boundary element method, or an analysis method combining both of these. Then, computer simulation is executed on the vehicle interior modeled by the vehicle interior modeling unit 103, and an impulse response between the speaker and the listening position is calculated.

  Here, in this embodiment, a 4-door sedan type vehicle is set as the vehicle, and the left ear EL and the right ear ER of the dummy head are set as listening positions. As speakers, a speaker FL installed at the lower part of the left front door, a speaker FR installed at the lower part of the right front door, a speaker RL installed at the lower part of the left rear door, and a speaker RR installed at the lower part of the right rear door. The four speakers are set. Under such setting, the simulation execution unit 104 starts four impulse responses FLEL, FREL, RLEL, RREL (hereinafter referred to as “four impulse responses”) between each of the four speakers FL, FR, RL, RR and the dummy head left ear EL. Collectively “impulse response Ip1”) and four impulse responses FLER, FERR, RLER, RRR between each of the four speakers FL, FR, RL, RR and the right ear ER of the dummy head (hereinafter collectively referred to as “impulse response Ip1”). "Impulse response Ip2") is output.

  The sound field tuning unit 20 corrects the impulse responses Ip1 and Ip2 output from the sound field simulation unit 10 and then listens by performing a convolution operation between the corrected impulse responses Ip1 ′ and Ip2 ′ and the evaluation sound. As shown in FIG. 3, a reference sound database unit 201, a target characteristic setting unit 202, a sound field correction unit 203, and a reference evaluation sound generation unit 204 are generated. And.

  The reference sound database unit 201 stores an impulse response Ip3 of an ideal sound environment (for example, an audio room, a listening room, etc.) as a sound environment for listening to sound as a database, and stores storage means such as a hard disk drive, for example. It is configured. The target characteristic setting unit 202 reads out the impulse response Ip3 of any acoustic environment stored in the reference acoustic database unit 201 and outputs the impulse response Ip3 to the sound field correction unit 203 and the reference evaluation sound generation unit 204. An input means for the user to input an instruction for the acoustic space is provided.

  The sound field correction unit 203 uses, for example, a least square method so that the impulse responses Ip1 and Ip2 output from the sound field simulation unit 10 approach the characteristics of the impulse response Ip3 output from the target characteristic setting unit 202. And the corrected impulse responses FLEL ′, FREL ′, RLEL ′, RREL ′ (hereinafter collectively referred to as “impulse response Ip1 ′”) and the corrected impulse responses FLER ′, FERR ′. , RLER ′, RRR ′ (hereinafter, these are collectively referred to as “impulse response Ip2 ′”).

  The sound field correction unit 203 is input with 2-channel music data or evaluation 2-channel data composed of M-sequence codes or the like as evaluation sounds SL and SR. Performs a convolution operation between the evaluation sounds SL and SR and the corrected impulse responses Ip1 ′ and Ip2 ′ to reproduce 2-channel data reflecting the acoustic characteristics of the vehicle interior space at the design stage in the evaluation sounds SL and SR Output as sounds CL and CR. The generation of the reproduced sounds CL and CR will be described in detail. As shown in FIG. 4, the sound field correction unit 203 includes eight corrected impulse responses FLEL ′, FREL ′, RLEL ′, RREL ′, and FLER ′. , FERR ′, RLER ′, RERR ′, one convolution operation circuit 206 is provided, and an impulse response which is an impulse response after correction between the speakers FL, RL and the listening positions EL, ER arranged on the left side of the vehicle interior Each of FLEL ', FLER', RREL ', RLER' and the left channel evaluation sound SL are subjected to a convolution operation, and between the speakers FR, RR and the listening positions EL, ER arranged on the right side of the vehicle interior Each of impulse responses FREL ', FERR', RREL ', RERR', which are impulse responses after correction, and evaluation of the right channel Convolving the SR is performed. The sound field correction unit 203 is provided with two adders 207a and 207b. Sounds reaching the left ear (listening position) EL of the dummy head are added together by the adder 207a and output as a reproduced sound CL. At the same time, sounds reaching the right ear (listening position) ER of the dummy head are added by the adder 207b and output as a reproduced sound CR.

  The sound field correction unit 203 has an IIR (Infinite Impulse Response) filter, and a parametric equalizer that corrects the frequency domain amplitude of the reproduced sounds CL and CR, and four speakers FL, FR, RL, and RR. There is provided time alignment correction means for correcting the delay of the reproduced sounds CL and CR based on the arrival times of the reproduced sounds CL and CR from the respective listening positions EL and ER. In addition, it replaces with a parametric equalizer and a time alignment correction means, has a FIR (Finite Impulse Response) filter, and the sound field correction | amendment part 203 is provided with the reverse filter which has a characteristic contrary to the acoustic characteristic of the modeled vehicle interior It is also good. The convolution operation circuit 206, the adders 207a and 207b, and the filter circuits described above may be realized by hardware, and functions equivalent to these may be realized by software and the reproduced sounds CL, CR may be calculated by calculation. It is good also as a structure which calculates | requires.

  With the above configuration, for example, in the target characteristic setting unit 202, when the impulse response Ip3 of the audio room is set as the reference acoustic environment, the impulse responses Ip1 and Ip2 in the vehicle interior are corrected so as to approach the impulse response Ip3. Further, if the amplitude and delay (including phase) of the reproduced sounds CL and CR are completely corrected, the sound field when the reproduced sounds CL and CR are actually output into the vehicle interior is the sound of the audio room. It is equivalent to a field, so that an ideal acoustic environment can be realized in the passenger compartment.

  Here, in the sound field correction in the vehicle interior, it is difficult to completely correct the amplitude and delay (including phase) of the reproduced sounds CL and CR over the entire frequency range of the audible range. Therefore, in the present embodiment, based on the sound quality evaluation of the reproduced sounds CL and CR in the sound quality evaluation unit 60 described later, the parametric equalizer, the time alignment correction means, the filter coefficients of the inverse filter, and the like are adjusted, and the sound in the vehicle interior The field is made as close as possible to the ideal acoustic environment.

  The reference evaluation sound generation unit 204 performs a convolution operation between the impulse response Ip3 of the reference acoustic environment set in the target characteristic setting unit 202 and the evaluation sounds SL and SR, thereby reproducing the reproduced sounds CL and CR. Reference evaluation sounds RL and RR for comparison are generated and output to a sound quality evaluation unit 60 described later.

  The noise adding unit 30 superimposes a noise signal to add noise to the reproduced sounds CL and CR output from the sound field tuning unit 20, and as shown in FIG. A sound database unit 302, a noise setting unit 303, and a synthesis unit 304 are provided. The traveling noise database unit 301 stores, for example, noise generated as the vehicle travels, such as engine sounds, tire sounds, and wind noises, in a database, and includes storage means such as a hard disk drive. Yes. The blower sound database unit 302 stores the air conditioner blown sound as a database, and includes storage means such as a hard disk drive.

  The noise setting unit 303 is for setting the noise to be added to the reproduced sounds CL and CR. The noise setting unit 303 includes input means for receiving the setting of the noise, and the traveling noise database unit 301 is based on the input noise setting. And the noise and the air conditioner blowing sound are read from the blowing sound database unit 302 and output to the combining unit 304.

  The synthesizer 304 adds the noise input from the noise setting unit 303 to the reproduced sounds CL and CR to generate reproduced sounds CL ′ and CR ′ on which the noise is superimposed, and outputs the reproduced sounds CL ′ and CR ′ to the acoustic effect adding unit 40. To do.

  The sound effect adding unit 40 has a function of correcting the loudness based on general human auditory characteristics with respect to the reproduced sounds CL ′ and CR ′ on which noise is superimposed, and a traveling noise, an air conditioner blowing sound, and the like. Equipped with an auto volume function that corrects the frequency of the playback sounds CL 'and CR' according to the noise, and an active noise control function that dynamically removes noise from the playback sounds CL 'and CR'. It is added to CL ′ and CR ′ and output to the sound field reproducing unit 50. Note that various algorithms relating to the acoustic signal processing can be verified by changing, adding, or deleting the acoustic effect given to the reproduced sounds CL ′ and CR ′ in the acoustic effect adding unit 40.

  The sound field reproducing unit 50 corrects the reproduced sounds CL ′ and CR ′ input from the sound effect adding unit 40 according to the characteristics of the headphones or the frequency characteristics of the speakers, and outputs them to these headphones or speakers. As shown in FIG. 6, a headphone characteristic correction unit 501, a speaker characteristic correction unit 502, and a crosstalk cancellation unit 503 are provided.

  When the reproduced sounds CL ′ and CR ′ are output from the headphones, the headphone characteristic correcting unit 501 reproduces the reproduced sound CL so that the frequency level of the sound is substantially uniform (flat) in the frequency domain. ', CR' is corrected according to the frequency characteristics of the headphones, and output to the headphones as headphone playback sounds HCL, HCR. On the other hand, the speaker characteristic correction unit 502 reproduces the reproduced sounds CL ′ and CR ′ so that the frequency levels in the frequency domain of the sound are substantially uniform (flat) when the reproduced sounds CL ′ and CR ′ are output from the speaker. Sounds CL ′ and CR ′ are corrected in accordance with the frequency characteristics of the speaker and output to the speaker via the crosstalk canceling unit 503.

  As shown in FIG. 7, the crosstalk cancellation unit 503 arranges two speakers SP1 and SP2 in front of the listener U, which are a speaker SP1 that outputs L channel sound and a speaker SP2 that outputs R channel sound. In order to suppress crosstalk (a phenomenon in which the sound from the speakers SP1 and SP2 of each channel wraps around to the opposite side) that occurs when the reproduced sounds CL ′ and CR ′ are reproduced from the speakers SP1 and SP2 Filter processing is applied to ', CR' and output to the speaker as speaker reproduction sounds SCL, SCR.

  As a result, the sound field in the vehicle interior modeled by the sound field simulation unit 10 can be auditioned using headphones or a speaker, and the test listener U can evaluate the sound field by hearing. In the sound field reproducing unit 50, the reproduced sounds CL and CR output from the sound field tuning unit 20 or the reproduced sounds CL ′ and CR ′ output from the noise adding unit 30 can be individually auditioned. Also good.

  The sound quality evaluation unit 60 is for evaluating the reproduced sounds CL ′ and CR ′. As shown in FIG. 8, the sound quality evaluation unit 60 is a processing unit 601, an IR (Impulse Response) characteristic display unit 602, and f (frequency). ) A characteristic display unit 603 and an objective sound quality evaluation value display unit 604 are provided.

  The processing unit 601 performs arithmetic processing for comparing the reproduced sounds CL ′ and CR ′ input from the sound field reproducing unit 50 with the evaluation sounds SL and SR and the reference evaluation sounds RL and RR. The result is output to each of the IR characteristic display unit 602, the f characteristic display unit 603, and the objective sound quality evaluation value display unit 604.

  More specifically, when the evaluation sounds SL and SR are M-sequence code data, the processing unit 601 obtains a cross-correlation function between the reproduced sounds CL ′ and CR ′ and the evaluation sounds SL and SR by calculation. The impulse response Ip4 in the transmission path of the evaluation sounds SL and SR including the sound field tuning unit 20, the noise adding unit 30, and the acoustic effect adding unit 40 is calculated and output to the IR characteristic display unit 602. The impulse response Ip3 of the reference acoustic environment set by the sound field tuning unit 20 is also input to the IR characteristic display unit 602. The IR characteristic display unit 602 includes an impulse response Ip4 and an impulse response Ip3. Display in a comparable manner. Furthermore, the processing unit 601 performs a Fourier transform process on each of the impulse responses Ip4 and Ip3, generates respective transmission frequency characteristics, and outputs them to the f characteristic display unit 603. The f characteristic display unit 603 displays these transmission frequency characteristics so that they can be compared.

  On the other hand, when the evaluation sounds SL and SR are music data, the processing unit 601 uses the BS. Objective sound quality evaluation values ODG (Objective Difference Grade) of reproduced sounds CL ′ and CR ′ are calculated according to the PEAQ (Perceived Evaluation of Audio Quality) standardized in 1387-1, and the calculation results are obtained as objective sound quality. The result is output to the evaluation value display unit 604. The objective sound quality evaluation value display unit 604 displays the objective sound quality evaluation value ODG.

  Here, the PEAQ method is a method for evaluating the subjective sound quality of human beings with objective numerical values, and is generally used for sound quality evaluation of compressed audio. However, in the passenger compartment, the amplitude characteristics and phase characteristics of the reproduced sounds CL ′ and CR ′ vary due to the frequency characteristics and directivity characteristics of the speakers, and the initial reflected sound, reverberation sound, and the like. That is, uncompressed music data is used as evaluation sounds SL and SR compared to music data compressed with a predetermined compression codec such as MP3 (MPEG1 Audio Layer-3) and WMA (Windows (registered trademark) Media Audio). In this case, since information indicating the current playback position, volume (signal level), etc. is not added, the synchronization between the playback sounds CL ′ and CR ′ and the reference evaluation sounds RL and RR and the signal level are shifted. In this case, accurate sound quality evaluation by the PEAQ method becomes difficult.

  Therefore, in the present embodiment, when the processing unit 601 performs the sound quality evaluation by the PEAQ method, the synchronization and the signal level of the reproduced sounds CL ′ and CR ′ and the reference evaluation sounds RL and RR are performed as follows. To match.

  That is, as shown in FIG. 9, the processing unit 601 first cuts out the reproduced sounds CL 'and CR' and the reference evaluation sounds RL and RR for a predetermined period (step S101). Then, the processing unit 601 calculates the cross-correlation of each of the extracted reproduced sounds CL ′ and CR ′ and the reference evaluation sounds RL and RR, and calculates the reproduced sound CL based on the peak position of the cross-correlation. A synchronization point A that is highly likely to be synchronized between ', CR' and the reference evaluation sounds RL, RR is obtained (step S102).

  Subsequently, the processing unit 601 executes processing for obtaining a more accurate synchronization point B in the vicinity of the synchronization point A. That is, the processing unit 601 sequentially calculates the objective sound quality evaluation value ODG while delaying the extracted reference evaluation sounds RR and RL in the forward / backward direction of the time axis by a predetermined time interval from the synchronization point A (step S103). (Step S104). Then, the processing unit 601 calculates an objective sound quality evaluation value ODG over the entire cut-out predetermined period (step S105: YES), and obtains an accurate synchronization point B as follows.

  That is, as shown in FIG. 10, the objective sound quality evaluation value ODG changes in accordance with the delay amount of the reference evaluation sounds RL and RR with respect to the reproduced sounds CL ′ and CR ′, and the reproduced sounds CL ′ and CR ′. And the reference evaluation sounds RL and RR are maximized by a delay amount synchronized with each other. Therefore, the processing unit 601 obtains the maximum point based on the objective sound quality evaluation value ODG obtained in steps S103 to S105, and uses the local maximum point as an accurate synchronization point B, and the reproduced sounds CL ′, CR ′, The reference evaluation sounds RL and RR are resynchronized (step S106).

  Next, the processing unit 601 performs a process for matching the signal levels of the reproduced sounds CL ′ and CR ′ with the reference evaluation sounds RL and RR. That is, the processing unit 601 sequentially calculates the objective sound quality evaluation value ODG while changing the signal levels of the reference evaluation sounds SL and SR cut out in step S101 by predetermined levels (step S107). Then, the processing unit 601 calculates the objective sound quality evaluation value ODG in the predetermined level range (step S109), and then performs the final objective sound quality evaluation value ODG in the vehicle interior modeled this time as follows. Ask for.

  That is, as shown in FIG. 11, the objective sound quality evaluation value ODG changes its value according to the signal levels of the reference evaluation sounds RL and RR with respect to the signal levels of the reproduced sounds CL ′ and CR ′, and the reproduced sound CL ′. , CR ′ and the reference evaluation sounds RL, RR are maximized when the signal levels match. Therefore, the processing unit 601 obtains the maximum point C based on the objective sound quality evaluation value ODG obtained in steps S107 to S109, and the objective sound quality evaluation value ODG at the maximum C is modeled this time. The final objective sound quality evaluation value ODG in the passenger compartment is output to the objective sound quality evaluation value display unit 604 (step S110), and this process is terminated.

  Through the above processing, even when uncompressed music is used as the evaluation sounds SL and SR, the objective sound quality evaluation value ODG based on the PEAQ method can be accurately obtained for the reproduced sounds CL ′ and CR ′.

  Next, the overall operation of the present embodiment will be described.

  As shown in FIG. 12, in the sound field simulation unit 10, the vehicle interior of the vehicle to be designed is modeled, and when the listening positions EL and ER in the vehicle interior are set, the sound field simulation unit 10 The simulation execution unit 104 calculates the impulse responses Ip1 and Ip2 between the listening positions EL and ER and the speakers FL, FR, RL, and RR, and outputs them to the sound field tuning unit 20 (step S201). At this time, the number of impulse responses output from the simulation execution unit 104 is M × N, where M is the number of listening positions and N is the number of speakers.

  Next, an ideal acoustic environment (for example, a listening room) to be reproduced in the passenger compartment is set in the sound field tuning unit 20, and when the impulse responses Ip1 and Ip2 are input to the sound field tuning unit 20, The sound field tuning unit 20 adjusts the sound field in the vehicle interior (sound field tuning), and outputs the reproduced sounds CL and CR reproduced in the adjusted sound field to the noise adding unit 30 (step S202). ). More specifically, in this step S202, the sound field correction unit 203 of the sound field tuning unit 20 corrects the impulse responses Ip1 and Ip2 so as to approach the impulse response Ip3 of the ideal acoustic environment, and the impulse response Ip1. 'And Ip2 are generated, and the impulse responses Ip1' and Ip2 'are convolved with the evaluation sounds SL and SR to generate reproduced sounds CL and CR. Next, the sound field correction unit 203 performs parametric equalizer processing on the reproduced sounds CL and CR so that the sound field in the vehicle interior reproduced by the reproduced sounds CL and CR is brought closer to the sound field of an ideal acoustic environment. Then, time alignment correction (or inverse filter correction) is performed, and the amplitude in the frequency domain, the arrival time from the speaker to the listening position, and the amplitude and phase in the time domain are corrected. At this time, the correction amount is varied by adjusting a parametric equalizer, a filter coefficient used for time alignment correction, etc., and the sound field tuning is performed by adjusting the sound field in the vehicle interior to approach the sound field of an ideal acoustic environment. .

  When the reproduction sounds CL and CR are input and the noise in the passenger compartment is set, the noise adding unit 30 superimposes the set noise on the reproduction sounds CL and CR, and generates the reproduction sounds CL and CR. It produces | generates and outputs to the acoustic effect addition part 40 (step S203). As a result, the reproduction sounds CL 'and CR' to be auditioned by the listener when the air-conditioning fan noise and noise generated during vehicle running are present in the passenger compartment.

  Next, when the reproduced sounds CL ′ and CR ′ are input to the sound effect adding unit 40, the sound effect adding unit 40 applies loudness correction, auto volume correction, active noise to these reproduced sounds CL ′ and CR ′. Various acoustic effects such as control correction are added and output to the sound field reproducing unit 50 (step S204). As a result, when the reproduced sounds CL and CR to which various acoustic effects are applied are reproduced in the vehicle interior where noise is present, the reproduced sounds CL 'and CR' to be auditioned by the listener are reproduced. That is, by changing the acoustic effect added by the acoustic effect adding unit 40, the reproduced sounds CL and CR reproduced in the vehicle interior where the noise is present are changed. Based on the reproduced sounds CL and CR at this time Can adjust the optimal sound effect.

  When the reproduced sounds CL ′ and CR ′ to which various acoustic effects are applied by the acoustic effect adding unit 40 are input to the sound field reproducing unit 50, the sound field reproducing unit 50 outputs the reproduced sounds CL ′ and CR ′. After correcting the reproduction sounds CL ′ and CR ′ so as to cancel the characteristics of the output device (speaker, headphones, etc.), the reproduction sounds CL ′ and CR ′ are output to the device (step S205). As a result, it is possible to audition the sound reproduced in the vehicle interior that is modeled this time, without the difference in the sampled sound depending on the device that reproduces the reproduced sounds CL ′ and CR ′.

  When the reproduced sounds CL ′ and CR ′ output from the acoustic effect adding unit 40 are input to the sound quality evaluation unit 60, the sound quality evaluation unit 60 selects the reproduced sounds CL ′ and CR ′, the evaluation sound SL, Based on the SR and the reference evaluation sounds RL and RR, the impulse response Ip4, the transmission frequency characteristic, and the objective sound quality evaluation value ODG are obtained by calculation, and the IR characteristic display unit 602, the f characteristic display unit 603 and the objective are respectively obtained. It is displayed on the sound quality evaluation value display unit 604 and can be compared with the reference evaluation sounds RL and RR (step S206).

  When the impulse response Ip4, the transmission frequency characteristic, and the objective sound quality evaluation value ODG are equal to or lower than a predetermined level (step S207: NO), the processing procedure returns to step S201, and each unit 10-60 Various parameter settings are changed. Specifically, the sound field simulation unit 10 changes the number of speakers, speaker positions, and the like, and the sound field tuning unit 20 changes tuning parameters such as filter coefficients of various filters, filter types, and the like. In the adding unit 40, the algorithm of the acoustic effect to be given to the reproduced sounds CL ′ and CR ′ is changed. Note that such various parameter changes may be performed by the control unit of the acoustic simulation apparatus 1 based on a predetermined algorithm, or may be changed by a user or the like.

  As described above, according to the present embodiment, noise is added to the reproduced sounds CL and CR generated by the sound field tuning unit 20, and the reproduced sounds CL ′ and CR ′ to which the noise is added are added. Therefore, the sound quality of the reproduced sounds CL ′ and CR ′ at the listening positions EL and ER is evaluated. Therefore, it is possible to accurately simulate the sound in the vehicle interior with noise.

  Further, according to the present embodiment, an acoustic effect is added to the reproduced sounds CL ′ and CR ′ to which the noise is added, and based on the reproduced sounds CL ′ and CR ′ after the acoustic effect is added. Therefore, it is possible to accurately simulate the sound when the reproduced sound CL, CR is reproduced with an acoustic effect and reproduced in a noisy vehicle interior.

  In addition, according to the present embodiment, since the same reproduction sound as the reproduction sounds CL ′ and CR ′ to be subjected to the sound quality evaluation is output to the sound emitting device such as a speaker or a headphone, the user can hear the reproduction sound by hearing. Can be evaluated.

  In addition, according to the present embodiment, the travel noise generated when the vehicle is traveling and the air-conditioning sound generated when the air conditioner provided in the vehicle is operating are made into a database, and these travels are performed. Since the noise and the air-conditioning sound can be appropriately selected as noise, it is possible to simulate the sound of the vehicle interior with various noises.

  Further, according to the present embodiment, since the impulse response Ip4, the transmission frequency characteristic, and the objective sound quality evaluation value ODG are obtained as sound quality evaluation, the sound quality of the reproduced sounds CL ′ and CR ′ is quantitatively evaluated. Based on the evaluation results, various parameters such as the acoustic effect, listening position (sound receiving point), speaker (sounding point) position, directivity, and various correction parameters can be adjusted. Therefore, the acoustic environment in the vehicle interior can be easily optimized, and the acoustic design in the vehicle interior and the development period can be shortened.

  Note that the above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified within the scope of the present invention. For example, in the embodiment described above, the acoustic simulation apparatus is configured to be realized by causing a computer to execute a program for acoustic simulation. However, the present invention is not limited to this, and each unit may be configured by dedicated hardware.

It is a block diagram which shows the functional structure of the acoustic simulation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of a sound field simulation part. It is a block diagram which shows the functional structure of a sound field tuning part. It is a figure for demonstrating the production | generation of the reproduction sound in a sound field tuning part. It is a block diagram which shows the functional structure of a noise addition part. It is a block diagram which shows the functional structure of a sound field reproducing part. It is a figure for demonstrating operation | movement of a crosstalk cancellation part. It is a block diagram which shows the functional structure of a sound quality evaluation part. It is a flowchart which shows the calculation procedure of the objective sound quality evaluation value. It is a figure for demonstrating the calculation procedure of the objective sound quality evaluation value. It is a figure for demonstrating the calculation procedure of the objective sound quality evaluation value. It is a flowchart which shows the whole operation | movement of an acoustic simulation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sound simulation apparatus 10 Sound field simulation part 20 Sound field tuning part 30 Noise addition part 40 Sound effect addition part 50 Sound field reproduction part 60 Sound quality evaluation part

Claims (16)

In an acoustic simulation device for simulating the acoustics of a vehicle interior of a vehicle ,
Impulse response calculation means for calculating a first impulse response from a sound generation point in the vehicle interior in which the vehicle interior structure and acoustic characteristics are modeled to a sound reception point ;
The first impulse response is corrected based on the second impulse response of the acoustic environment which is a reference acoustic environment reproduced in the vehicle interior and is ideal as an acoustic environment for viewing and listening to the sound, and based on the corrected first impulse response Sound field correction generating means for generating a reproduced sound signal indicating the reproduced sound at the sound receiving point in the vehicle interior;
Noise adding means for adding a noise signal of noise generated when the vehicle travels to the reproduced sound signal generated by the sound field correction generating means;
Sound quality evaluation means for calculating a characteristic value indicating the sound quality of the reproduced sound at the sound receiving point based on the reproduced sound signal to which the noise signal is added ,
An acoustic simulation apparatus characterized in that the position of the sounding point or the position of the sound receiving point can be adjusted based on the evaluation result by the sound quality evaluation means . An acoustic effect adding means for adding an acoustic effect to the reproduced sound signal to which the noise signal is added;
The sound quality evaluation means calculates a characteristic value indicating the sound quality of the reproduced sound at the sound receiving point, based on the reproduced sound signal after the acoustic effect is added ,
The acoustic simulation apparatus according to claim 1 , wherein the acoustic effect can be adjusted based on an evaluation result by the sound quality evaluation unit .   3. The acoustic simulation apparatus according to claim 1, further comprising output means for outputting the same reproduced sound signal as the reproduced sound signal input to the sound quality evaluating means to a sound emitting device. First storage means for storing a plurality of data of a structure indicating the structure of the vehicle interior;
Second storage means for storing data of acoustic characteristics of members disposed in the vehicle interior;
Modeling means for selecting data of the structure and data of acoustic characteristics and modeling the vehicle interior;
Sound receiving position setting means for setting the position of the sound receiving point in the modeled vehicle interior ,
4. The acoustic simulation apparatus according to claim 1 , wherein the position of the sound receiving point can be adjusted by the sound receiving position setting means based on an evaluation result by the sound quality evaluating means . Third storage means for storing a plurality of the second impulse responses for each reference acoustic environment;
The acoustic simulation apparatus according to claim 1, further comprising: a reference acoustic environment setting unit that selects the reference acoustic environment.   The acoustic simulation apparatus according to claim 1, wherein the sound field correction generation unit corrects the first impulse response so as to approach the second impulse response. Fourth storage means for storing in advance data of traveling noise generated when the vehicle is traveling;
A fifth storage means for storing in advance data of an air conditioner blowing sound generated when an air conditioner provided in the vehicle is operating;
7. The noise adding means adds the noise signal to the reproduction sound signal based on the running noise data, or the running noise data and the air conditioner blowing sound data. The acoustic simulation apparatus described in 1.   The sound effect adding means performs at least one sound effect of loudness, correction of frequency characteristics according to the noise signal, and active noise control on the reproduced sound signal to which the noise signal is added. An acoustic simulation apparatus characterized by being added. The output means includes
The characteristic correction means for correcting the reproduction sound signal according to the frequency characteristic of the sound emitting device so that the frequency level of the sound reproduced by the sound emitting device becomes substantially uniform. 3. The acoustic simulation apparatus according to 3. The output means includes
The acoustic simulation apparatus according to claim 3, further comprising a crosstalk canceling unit configured to perform correction for preventing the crosstalk generated when the sound is reproduced by the sound emitting device on the reproduction signal. . The sound field correction generation means calculates a reference evaluation sound signal by a convolution operation of the second impulse response and the evaluation sound signal of the M-sequence code ,
Generating the reproduced sound signal by a convolution operation of the corrected first impulse response and the evaluation sound signal;
The sound quality evaluation means is
The acoustic simulation apparatus according to claim 1, wherein a third impulse response is calculated as the characteristic value based on a cross-correlation function between the evaluation sound signal and the reproduced sound signal.   12. The acoustic simulation apparatus according to claim 11, wherein the sound quality evaluation unit calculates a transmission frequency characteristic obtained by performing a Fourier transform on the third impulse response as a characteristic evaluation value. The sound field correction generation means calculates a reference evaluation sound signal by a convolution operation of the second impulse response and the evaluation sound signal,
Generating the reproduced sound signal by a convolution operation of the corrected first impulse response and the evaluation sound signal;
The sound quality evaluation means is
When the evaluation sound signal is a music signal, an objective sound quality evaluation value (Objective Difference Grade) is calculated according to a PEAQ (Perceived Evaluation of Audio Quality) method based on the reproduction sound signal and the reference evaluation sound signal. The acoustic simulation apparatus according to claim 1, wherein the acoustic simulation apparatus is calculated as a characteristic value. The sound quality evaluation means is
When the evaluation sound signal is an uncompressed music signal, based on the cross-correlation between the reproduction sound signal and the reference evaluation sound signal, signal synchronization between the reproduction sound signal and the reference evaluation sound signal is performed, The acoustic simulation apparatus according to claim 13, wherein the objective sound quality evaluation value that is maximized when a signal level of the reference evaluation sound signal is changed is calculated. In an acoustic simulation program for simulating acoustics in a vehicle cabin, a computer is provided.
Means for calculating a first impulse response from a sound generation point in the vehicle interior to a sound reception point in which the structure and acoustic characteristics of the vehicle interior are modeled;
The first impulse response is corrected based on the second impulse response of an acoustic environment that is a reference acoustic environment reproduced in the vehicle interior and is ideal as an acoustic environment for viewing and listening to sound, and based on the corrected first impulse response Means for generating a reproduced sound signal indicating a reproduced sound at a sound receiving point in the vehicle interior;
Means for adding a noise signal to the reproduced sound signal; and
Means for calculating a characteristic value indicating sound quality of the reproduced sound at the sound receiving point based on the reproduced sound signal to which the noise signal is added ;
An acoustic simulation program that functions as means for enabling adjustment of the position of the sounding point or the position of the sound receiving point based on the evaluation result by the sound quality evaluation means .   The computer-readable recording medium which recorded the acoustic simulation program of Claim 15.

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