JP2015147516A - Method and device for calculating additional sound volume of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additional sound volume calculating system capable of greatly reducing tuning man hour for an additional sound volume from an active type effective sound generator.SOLUTION: A method includes calculating a sound volume of effective sound output from speakers in a cabin with an active type effective sound generator on-vehicle and added to real engine acceleration sound. There are included: a cabin engine acceleration sound extracting device (2) for extracting order components according to a rotation frequency about engine acceleration sound measured in the cabin; an ideal acceleration sound creating device (3) for creating ideal acceleration sound close to real engine acceleration sound, based on the order components of the engine acceleration sound; a binaural measuring device (1) for outputting sound from a reference sound source from the speakers and recording so as to calculate transfer characteristic of each of the speakers; and a speaker reproduction sound calculating device (4) for calculating a sound volume of reproduction sound output from the speakers as effective sound, based on the ideal acceleration sound and the transfer characteristic of each of the speakers.

Description

  The present invention relates to an additional sound volume calculation method and an additional sound volume calculation device for a vehicle, and in particular, is generated from a plurality of speakers in a vehicle interior and added to an actual engine acceleration sound by an active sound effect generator mounted on the vehicle. The present invention relates to a method and apparatus for calculating the volume of a sound effect.

  While vehicle noise is required to be quieter due to outside noise regulations, driving noise (sound effect), which is one of the attractive qualities for passengers, is output from the audio speaker to the vehicle interior to produce actual engine acceleration sound. Patent Document 1 discloses an active sound effect generator (also referred to as Active Sound Control System) that allows a more dynamic running sound to be experienced without being restricted by outside noise regulations. Etc. are proposed.

JP 2012-162143 A

  However, in a system represented by Patent Document 1, in order to determine an appropriate additional sound volume output from a speaker as a sound effect (acceleration sound), it is necessary to repeat an actual running test for sensory evaluation, It is not preferable because tuning of the additional volume of the acceleration sound requires a huge amount of time.

  For example, in consideration of adding the number of audio speakers arranged in the passenger compartment as an additional sound volume and adding an N-order component of a frequency corresponding to the engine rotation, combinations of several tens to several hundreds are conceivable. It takes a lot of time to tune the additional volume.

  The target sound at the occupant's ear position can be reproduced with a speaker using a technique called MISO. Although this technique can reproduce the ideal acceleration sound at the assumed seating position, However, if the seating position is shifted, the ideal acceleration sound may not be reproduced, and it is not preferable as a method for reproducing the target sound in the passenger compartment where various seating positions can be selected. Furthermore, in the most common passenger cars, people can naturally sit in the passenger seat and the rear seat, and in that case, it would be different from the ideal running sound (sound effect), which is not preferable. .

  The present invention has been made paying attention to such a problem, and in order to further optimize the additional volume produced and added by the active sound effect generator, particularly the tuning man-hour for the added volume has been greatly increased. An additional sound volume calculation method that can be reduced is provided.

  The present invention provides a method for calculating the volume of sound effects produced and added from a plurality of speakers in a vehicle interior by an active sound effect generator mounted on the vehicle, and the engine speed for engine acceleration sounds measured in the vehicle interior. A vehicle interior engine acceleration sound extraction process for extracting the order component according to the engine acceleration, an ideal acceleration sound generation process for generating an ideal acceleration sound close to the actual engine acceleration sound based on the order component of the engine acceleration sound, and speaker transmission characteristics The sound from the reference sound source for measurement is output from each speaker and binaural recorded, and then the binaural measurement process for calculating the transfer characteristics of each speaker, and from each speaker based on the ideal acceleration sound and the transfer characteristics of each speaker. And a speaker playback sound calculation step for calculating the volume of the playback sound to be sounded and added.

  According to the present invention, in order to further optimize the additional sound volume generated and added by the active sound effect generator, the appropriate additional sound volume is considered in consideration of the difference in the transfer function from the sound source position depending on the seating position in the vehicle interior. Can be obtained by automatic calculation, thereby greatly reducing the number of tuning steps for the additional volume of the acceleration sound.

1 is a schematic explanatory diagram of an entire system for an additional sound volume calculation method according to the present invention. The functional block diagram which shows the detail of the vehicle interior engine acceleration sound extraction apparatus in FIG. The functional block diagram which shows the detail of the ideal acceleration sound production apparatus in FIG. The functional block diagram which shows the detail of the binaural measuring device of the vehicle interior speaker transmission characteristic in FIG. The functional block diagram which shows the detail of the speaker reproduction sound calculation apparatus in FIG. Explanatory drawing which shows the example of arrangement | positioning of the speaker in a vehicle-mounted audio system.

  1 to 6 show a more specific form for carrying out the additional sound volume calculation method according to the present invention. In particular, FIG. 1 shows a schematic configuration of the entire additional sound volume calculation system, and FIGS. 2 to 5 show each part in FIG. Details of each function are shown.

  The system shown in FIG. 1 is roughly divided into a binaural measurement device 1 for vehicle interior speaker transmission characteristics, a vehicle interior engine acceleration sound extraction device 2, an ideal acceleration sound creation device 3, and a speaker reproduction sound calculation device 4. The As the speakers, as shown in FIG. 6, for example, speakers 5R and 5L and 6R and 6L arranged in pairs on the left and right front doors and rear doors of the vehicle are assumed as stereo output devices of the in-vehicle audio device. Yes. The system shown in FIG. 1 includes, for example, a general-purpose personal computer including elements of a binaural measurement device 1, a vehicle interior engine acceleration sound extraction device 2, an ideal acceleration sound creation device 3, and a speaker reproduction sound calculation device 4. Built with

  The vehicle interior engine acceleration sound extraction device 2 in FIG. 1 measures the current (actual) engine acceleration sound in the vehicle interior and performs an order ratio analysis, so that the engine acceleration sound corresponding to the engine speed during vehicle acceleration is calculated. It has a function of extracting the order component.

  The ideal acceleration sound creating device 3 in FIG. 1 creates an ideal acceleration sound during acceleration by the order ratio component volume adding device based on the order component of the acceleration sound extracted and created by the vehicle interior engine acceleration sound extracting device 2. It has the function to do. The ideal acceleration sound created by the ideal acceleration sound creation device 3 is compared and confirmed with the actual engine acceleration sound. If the error is large, it is automatically corrected as needed by inputting the additional volume at the target rotation order, and more actual engine acceleration is achieved. It is completed as an ideal acceleration sound close to sound.

  Similarly, the binaural measuring device 1 for the vehicle interior speaker transmission characteristic of FIG. 1 is for determining the vehicle interior speaker transmission characteristic as the name suggests, and the vehicle interior in which the reference sound source for measuring the transmission characteristic is shown in FIG. Are output from the respective speakers 5R, 5L and 6R, 6L, binaurally recorded on the so-called dummy type measuring device main body imitating a human body, and then transmitted from the speakers 5R, 5L and 6R, 6L. It has a function to calculate characteristics. The dummy type measuring device main body will be described later.

  Further, the speaker reproduction sound calculation device 4 in FIG. 1 calculates the difference in sound pressure level between the current (actual) engine acceleration sound and the ideal acceleration sound created by the ideal acceleration sound creation device 3, and this sound pressure difference. By using the calculated values and the transfer characteristics of the speakers 5R, 5L and 6R, 6L, the ideal sound is output from the order ratio component volume adding device. In this case, in consideration of the case where the seating positions are finally different (for example, before and after seating, left and right or up and down positions), the frequency characteristics are smoothed as will be described later, whereby each speaker 5R, 5L. And the additional sound volume from 6R and 6L is determined.

  FIG. 2 shows details of the vehicle interior engine acceleration sound extraction device 2 in FIG. As shown in FIG. 2 (A), acceleration sound associated with actual vehicle travel is collected by recording or the like in the vehicle interior, and the acceleration sound in the current vehicle interior is input to a predetermined file to obtain a vehicle interior acceleration sound file. (Step S1). Since the acceleration sound in the passenger compartment includes sounds other than the acceleration sound accompanying the engine rotation, in order to extract only the engine acceleration sound due to the engine rotation, the engine-specific order to be extracted is determined. After the determination (step S2), the analysis by the order ratio analyzer 7 is executed (step S3). By the analysis processing by the order ratio analyzer 7, only the order component acceleration sound resulting from the engine rotation, that is, the engine acceleration sound is extracted, and is output and recorded in a predetermined file (step S4).

  FIG. 2B shows details of the order ratio analyzer 7 in step S2 of FIG. 2A. The order ratio analyzer 7 includes an FFT device 8, a rotational speed calculator 9, and an order component. It is comprised with the extraction apparatus 10. FIG. As a process in each of these elements, a file equivalent to the file in step S1 in FIG. 2A is input as a sound source file (step S5), and the order of the target engine speed is input. (Step S6), the FFT device 8, the rotation speed calculation device 9 and the order component extraction device 10 sequentially perform predetermined calculations (steps S7 to S9), so that the target engine speed of the engine acceleration sound is determined. Only the order component is extracted and output (step S10).

  In this case, as a matter of course, since the order of the target engine speed is not single, there are a plurality of orders, so the above calculation starting from the input of the order of the target engine speed is repeated a plurality of times, Finally, as in step S4 of FIG. 2A, acceleration sounds of a plurality of order components resulting from engine rotation are extracted as engine acceleration sounds, which are output to a predetermined file and recorded. The In the following description, the engine acceleration sound acquired here is abbreviated as the current acceleration sound.

  FIG. 3 shows details of the ideal acceleration sound creating apparatus 3 in FIG. As shown in FIG. 2A, the ideal acceleration sound generation device 3 inputs the engine acceleration sound file acquired in step S4 of FIG. 2A (step S11) and (B) of FIG. ) Is input in the same manner as in step S6 (step S12), and is added in accordance with the preset order of the target engine speed as a process in step S13. Enter the volume. And as a process in step S14, an ideal sound, that is, an ideal engine acceleration sound is formed by executing the process in the order ratio component volume adding device 11.

  Further, in the subsequent step S15, whether the ideal sound is confirmed or not (OK / NG determination) is determined (OK / NG determination) as confirmation of the formed ideal sound. Is output and recorded (step S16), and if “NG”, each process from step S13 is repeated until the ideal sound is completed in step S16.

  In the following description, the completed ideal sound acquired here is abbreviated as “ideal acceleration sound”. In addition, whether or not the ideal sound is good or bad in step S15 is confirmed as a sound source file once on a desk regardless of whether it is “OK” or “NG”. Therefore, the determination of the quality of the ideal sound here is based on the premise that the image of the target sound (ideal sound) can be grasped in advance.

  FIG. 3B shows the details of the order ratio component volume adding device 11 in step S14 of FIG. 3A. The order ratio component volume adding device 11 here is an FFT device 12, a rotation speed calculating device. 13. In addition to the order component extraction device 14 and each order component waveform confirmation device 15, each order component volume addition device 16, inverse FFT device 17 and sound source file creation device 18 are provided. In steps S17 and S18, as the processing in steps S11 and S13 in FIG. 5A, the engine acceleration sound file is input and the order of the target engine speed is input, and the FFT device 12, the rotation speed is input. The processing of the calculation device 13, the order component extraction device 14, and each order component waveform confirmation device 15 is executed (steps S19 to S22).

  Further, in step S23, as the processing of step S13 in FIG. 9A, an additional volume corresponding to the target engine speed order set in advance is input, and each order component volume adding device 16, Processing in the inverse FFT device 17 and the sound source file creation device 18 is executed (steps S24 to S26). Thereby, a volume added sound source file is formed in step S27, which corresponds to the completed ideal sound file in step S16 in FIG. 3A, that is, the ideal acceleration sound.

  FIG. 4 shows a system configuration for measurement by the binaural measuring device 1 shown in FIG. In the system configuration of FIG. 4, in addition to the binaural measurement device main body 19, in addition to the signal generation device 20, the in-vehicle audio amplifier 22 and the in-vehicle speakers 5R, 5L and 6R, 6L, an acoustic signal recording device 23 and a transfer characteristic calculation device 24 are provided. include. As is well known, the binaural measuring device main body 19 has a binaural recording microphone embedded in left and right ear equivalent parts of a dummy head simulating a human body, and can be used in any seat (seat) in a vehicle interior. ). The in-vehicle audio amplifier 22 is mounted on the vehicle as a main element of the in-vehicle audio system. Similarly, the in-vehicle speakers 5R, 5L and 6R, 6L are, for example, front and right front doors of the vehicle as shown in FIG. The rear doors are arranged in pairs.

  The signal generator 20, the sound signal recording device 23, and the transfer characteristic calculation device 24 in the system of FIG. 4 are the vehicle interior engine acceleration sound extraction device 2, the ideal acceleration sound creation device 3, and the speaker reproduction sound calculation shown in FIG. It may be constructed with a single personal computer together with the device 4 or the like, but the three of the signal generator 20, acoustic signal recording device 23 and transfer characteristic calculation device 24 in the system of FIG. 4 are constructed with a single personal computer. May be.

  In this binaural measurement, as shown in FIG. 4, the sound of a sound source prepared in advance for transfer characteristic measurement is generated by a signal generator 20 and amplified via an in-vehicle audio amplifier 22, and then each in-vehicle speaker. Output (reproduce) from 5R, 5L and 6R, 6L. The reproduced sound output from each of the in-vehicle speakers 5R, 5L and 6R, 6L is binaurally recorded by the acoustic signal recording device 23. Further, the transfer characteristic calculation device 24 of FIG. 4 receives a recording signal from the acoustic signal recording device 23 and performs a predetermined calculation to correspond to the left and right ears at the dummy seating positions from the on-vehicle speakers 5R, 5L and 6R, 6L. A transfer function (impulse response) up to the position is calculated, and the transfer functions for each of the in-vehicle speakers 5R, 5L and 6R, 6L are output and recorded in a predetermined file.

  Further, FIG. 5 shows details of the speaker reproduction sound calculation device 4 shown in FIG. As shown in the figure, the speaker reproduction sound calculation device 4 includes a difference value calculation device 27, an order ratio component volume addition device 28, a volume level smoothing device 29, and an inverse FFT device 30 in addition to the two FFT devices 25 and 26. Consists of. Then, the transfer function for each speaker 5R, 5L and 6R, 6L acquired by the binaural measuring device 1 of FIG. 4 is given to one FFT device 25, and the ratio of the output levels of the front and rear speakers 5R, 5L and 6R, 6L is the order. Each is input to the specific component volume adding device 28.

  In this case, not all the transfer functions for each of the speakers 5R, 5L and 6R, 6L acquired by the binaural measuring device 1 of FIG. 4 are directly input to one FFT device 25, but only the transfer function of the main transfer path. Shall be selected and entered. Here, for example, the transfer function from the right front speaker 5R to the right ear position in the vehicle interior, the transfer function from the left front speaker 5L to the left ear position, and the right rear speaker 6R to the right ear position. And the transfer function from the left rear speaker 6L to the left ear position are selected and input to one FFT device 25.

  Also, the ideal acceleration sound acquired by the ideal acceleration sound generation device 3 of FIG. 3 and the current acceleration sound acquired by the vehicle interior engine acceleration sound extraction device 2 of FIG. 2 are input to the other FFT device 26. . Further, it is assumed that a preset smoothing amount is input to the volume level smoothing device 29 in FIG. Then, in addition to the two FFT devices 25 and 26, the respective processes in the difference value calculating device 27, the order ratio component volume adding device 28, and the inverse FFT device 30 are executed.

  Here, after calculating the difference in sound pressure level between the current acceleration sound and the ideal acceleration sound, it is necessary for the ideal acceleration sound by using the sound pressure difference and the transfer characteristics of the speakers 5R, 5L and 6R, 6L. Finally, as shown in FIG. 5, the output volume from each speaker 5R, 5L and 6R, 6L corresponding to the additional volume is determined, and this is obtained from the inverse FFT device 30. Shall be output. That is, by using the transfer function for each speaker 5R, 5L and 6R, 6L acquired in advance, the difference between the current acceleration sound and the ideal acceleration sound is obtained by calculation, and the additional volume obtained from the transfer function is calculated backward. The method to ask for is taken. However, the phase component of the transfer function is ignored, and a predetermined calculation process is performed based only on the sound pressure.

  In this case, as the smoothing process in the sound volume level smoothing device 29 in FIG. 5, a smoothing process of frequency characteristics considering the case where the seating position in the passenger compartment is different (for example, before and after seating, left and right or up and down position). By doing so, an additional volume as a reproduction sound output from each speaker 5R, 5L and 6R, 6L is determined and output.

  In addition, as described above, when the frequency characteristics are calculated based only on the transfer functions of the speakers 5R, 5L and 6R, 6L, a frequency that becomes a so-called dip that is hardly transmitted even if it is output in a narrow space such as a passenger compartment. On the other hand, there is a frequency that can be easily transmitted even when sound pressure is applied from a small amount of speakers. If this characteristic is used as it is, an “ideal acceleration sound” may be realized only at the transfer function measurement position. Therefore, in order to achieve the “ideal acceleration sound” at other positions equally, as a part of the volume level smoothing process or as another correction process, the frequency characteristics of the transfer functions of the speakers 5R, 5L and 6R, 6L. It is desirable to add a waveform peak / dip mitigation process using a low-pass filter or the like.

  Furthermore, by providing a threshold at a specific level in the frequency characteristics, and adding control to supplement the data before and after the dip or peak, both when the frequency characteristics of the transfer function exceed the threshold and when it is less than the threshold, The sound that is far from the ideal acceleration sound is not heard, and tuning that reproduces the acceleration sound close to the ideal acceleration sound at any seating position becomes possible.

  Here, the advantages of the present embodiment other than those described above are listed as follows (a) to (e).

  (A) Since the sound pressure at the left and right ear positions can be calculated, the ideal acceleration sound localization can be changed by the left and right sound difference.

  (A) For the original sound that does not take into account the ideal acceleration sound, by actually adding the sound calculated in the calculation, it is possible to confirm the acceleration sound that would actually be heard on the desk.

  (C) By performing the above-described series of processing, the volume at each frequency to be output from each frequency is instantaneously calculated and listed, thereby reducing the number of tuning steps ranging from tens to hundreds.

  (D) By controlling only the sound pressure, it is possible to effectively avoid a trouble phenomenon that a sound image that is likely to be in a stereo sound source or the like is pinpointed and separated from an actual sound heard from the engine side.

  Furthermore, if an example of a series of processing procedures executed in the system shown in FIGS. 1 to 5 is rearranged in time series, the following (1) to (7) are obtained. However, it is of course possible to replace the subsequent part of some processing procedures within a range not departing from the gist of the present invention.

  (1) As shown in FIG. 5, a transfer function (impulse response) that is a frequency characteristic from each speaker 5R, 5L and 6R, 6L to a seating position in the vehicle is measured by a binaural measurement method.

  (2) As shown in FIG. 3, the current acceleration sound in the passenger compartment is measured.

  (3) As shown in FIG. 4, an ideal acceleration sound is created.

  (4) As shown in FIG. 6, the difference between the sound pressure levels of the current acceleration sound and the ideal acceleration sound is calculated.

  (5) As shown in FIG. 6, based on the transfer function measured in (1), the main transfer components are determined from the speakers 5R, 5L and 6R, 6L.

  (6) As shown in FIG. 6, based on the main transmission component determined in (5), the frequency characteristics of the additional sound volume from the speakers 5R, 5L and 6R, 6L are calculated.

  (7) As shown in FIG. 6, the frequency characteristics calculated in (6) are smoothed as part of the volume level smoothing in consideration of different seating positions, and the speakers 5R, 5L and 6R, 6L are executed. Determine the additional volume from.

  Then, the algorithm for such a procedure can be converted into software and installed in, for example, a personal computer that is the base of the system shown in FIG. 1, so that the volume at each frequency can be instantaneously calculated and listed. As a result, it is possible to significantly reduce the number of tuning steps for combinations ranging from several tens to several hundreds as in the prior art.

1 ... Binaural measurement device for vehicle speaker transmission characteristics (transmission characteristic calculation means)
2 ... In-vehicle engine acceleration sound extraction device 3 ... Ideal acceleration sound creation device 4 ... Speaker reproduction sound calculation device 5R, 5L ... Speaker 6R, 6L ... Speaker 19 ... Binaural measurement device main body

Claims (4)

A method of calculating a volume of a sound effect output from a plurality of speakers in a vehicle interior and added to an actual engine acceleration sound by an active sound effect generator mounted on a vehicle,
A vehicle interior engine acceleration sound extraction step for extracting an order component corresponding to the engine speed from the engine acceleration sound measured in the vehicle interior;
An ideal acceleration sound creating step for creating an ideal acceleration sound close to the actual engine acceleration sound based on the order component of the engine acceleration sound;
A transfer characteristic calculation step of calculating the transfer characteristic of each speaker after outputting the sound from the reference sound source for measuring the transfer characteristic of the speaker from each speaker and recording it at the position corresponding to the ear of the passenger;
A speaker reproduction sound calculation step of calculating the volume of the reproduction sound output as a sound effect from each speaker based on the ideal acceleration sound and the transmission characteristics of each speaker;
The additional volume calculation method of the vehicle characterized by including.   The transfer characteristic calculation step is a binaural measurement step of calculating a transfer characteristic of each speaker after outputting a sound from a reference sound source for speaker transfer characteristic measurement from each speaker and binaural recording. 2. A method for calculating an additional volume of a vehicle according to 1. An apparatus for calculating a volume of a sound effect output from a plurality of speakers in a vehicle interior and added to an actual engine acceleration sound by an active sound effect generator mounted on the vehicle,
A vehicle interior engine acceleration sound extraction means for extracting an order component corresponding to the engine speed from the engine acceleration sound measured in the vehicle interior;
Ideal acceleration sound creating means for creating an ideal acceleration sound close to the actual engine acceleration sound based on the order component of the engine acceleration sound;
Transmission characteristics calculating means for calculating the transmission characteristics of each speaker after outputting the sound from the reference sound source for measuring the transmission characteristics of the speaker from each speaker and recording it at the position corresponding to the ears of the passenger;
Speaker playback sound calculation means for calculating the volume of the playback sound output as a sound effect from each speaker based on the ideal acceleration sound and the transfer characteristics of each speaker;
An additional sound volume calculation device for a vehicle, comprising:   The transfer characteristic calculation means is a binaural measurement device that calculates a transfer characteristic of each speaker after outputting sound from a reference sound source for speaker transfer characteristic measurement from each speaker and binaurally recording it. 4. The additional sound volume calculation device for a vehicle according to 3.

Images