Sound control device, sound control method and sound control program

Abstract

To provide a sound control device that can appropriately perform frequency characteristic adjustment or the like to perform sound emission of music while removing acoustic influence in an in-vehicle space.SOLUTION: A sound control device comprises: a frequency characteristics analyzing section 1 that determines whether or not an adjustment value which is used for adjustment of frequency characteristics of sound data in performing sound emission is updated on the basis of at least one of sound data corresponding to sound to be emitted and sound collection data corresponding to the sound collected by a microphone MC that collects sound in an in-vehicle space where the sound is emitted; and an equalizer value setting section 2 that updates the adjustment value when it is determined that the updating is performed, and causes the sound corresponding to the sound data, in which the frequency characteristics is adjusted, to emit from a speaker SP using the adjustment value after the updating.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present application relates to the technical fields of a sound control device, a sound control method, and a sound control program. More specifically, the present application relates to the technical fields of a sound control device and a sound control method for controlling a sound adjustment mode, and a sound control program used in the sound control device. [Background technology]

[0002] For example, an audio device is installed in a vehicle, and music is enjoyed while traveling. Here, the acoustic characteristics due to the shape of the interior space of the vehicle (hereinafter, the interior space is simply referred to as the "vehicle interior space") vary depending on the vehicle model, as well as the number of passengers in the vehicle, their riding positions, or the influence of sounds caused by the travel environment (for example, so-called wind noise, road noise, or sounds caused by weather conditions such as rain). Therefore, in order to enjoy music corresponding to the original sound even when the acoustic characteristics change, it is necessary to adjust the frequency characteristics, etc. when emitting the original sound into the vehicle interior space, including correcting them to correspond to the acoustic characteristics of the vehicle interior space. When making such adjustments including corrections, conventionally, a predetermined test sound is emitted into the vehicle interior space while the vehicle is stopped, and the acoustic characteristics are evaluated. However, in this case, adjustments including corrections that reflect the travel environment of the vehicle and the riding positions of the passengers cannot be made. Therefore, it is being considered to make adjustments including corrections to the frequency characteristics, etc., using music emitted into the vehicle interior space while traveling. An example of a prior art related to such considerations is the technology described in Patent Document 1 below. The technology described in Patent Document 1 is configured to correct and adjust the frequency characteristics and the like according to the music being played while the vehicle is moving. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-299957 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using the technology described in Patent Document 1, there was a problem that adjustments including corrections could not be made appropriately when, for example, the influence of the moving environment was large or the frequency characteristics of the source sound to be emitted itself were biased, and the measurement conditions specified for adjustments including corrections were not provided.

[0005] Therefore, the present application has been made in consideration of the above-mentioned problems, and one example of the objective is to provide a sound control device and sound control method that are capable of emitting music by appropriately adjusting frequency characteristics, etc. while eliminating the acoustic influences in the vehicle interior space, as well as a sound control program for use in the sound control device. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 comprises a determination means for determining whether or not to perform an update process for updating an adjustment value used to adjust the frequency characteristics of the original sound information when emitting the original sound, based on at least one of original sound information corresponding to the original sound to be emitted and sound collection information corresponding to the sound collected by a sound collection means that collects sound in the space in which the original sound is emitted, and an update means for updating the adjustment value when it is determined that the update process is to be performed, and for emitting from the sound emission means the original sound corresponding to the original sound information whose frequency characteristics have been adjusted using the updated adjustment value.

[0007] In order to solve the above problem, the invention described in claim 9 comprises a speed information acquisition means for acquiring speed information indicating the speed of movement in the space in which the original sound is emitted, a determination means for determining whether or not to perform an update process for updating an adjustment value used to adjust the frequency characteristics of original sound information corresponding to the original sound when emitting the original sound based on the acquired speed information, and an update means for updating the adjustment value when it is determined that the update process is to be performed, and for emitting the original sound corresponding to the original sound information whose frequency characteristics have been adjusted using the updated adjustment value from the sound emission means.

[0008] In order to solve the above problem, the invention described in claim 10 provides a sound control method that is executed in a sound control device that includes a judgment means and an update means and is connected to a sound collection means and a sound emission means, and includes a judgment step in which the judgment means judges whether or not to perform an update process for updating an adjustment value used to adjust the frequency characteristics of the original sound information when emitting the original sound, based on at least one of original sound information corresponding to the original sound to be emitted and sound collection information corresponding to the sound collected by the sound collection means that collects the sound of the space in which the original sound is emitted, and an update step in which, when it is determined that the update process is to be performed, the update means updates the adjustment value, and the sound emission means emits the original sound corresponding to the original sound information whose frequency characteristics have been adjusted using the updated adjustment value.

[0009] In order to solve the above problem, the invention described in claim 11 is configured to cause a computer connected to a sound collection means and a sound emission means to function as a sound control device described in any one of claims 1 to 9. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a schematic configuration of a sound control device according to an embodiment; [Diagram 2] 1 is a block diagram showing a schematic configuration of a sound field adjustment device according to an embodiment; [Diagram 3] 5 is a flowchart showing a sound field adjustment process according to the embodiment. [Figure 4]5A to 5C are conceptual diagrams illustrating details of a sound field adjustment process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing a schematic configuration of a sound control device according to the embodiment.

[0012] As shown in FIG. 1, the sound control device S of the embodiment is configured to include a determination means 1 connected to a sound collection means MC such as a microphone, and an update means 2 connected to a sound emission means SP such as a speaker.

[0013] In this configuration, the judgment means 1 judges whether or not to perform an update process for updating an adjustment value used to adjust the frequency characteristics of the original sound information when emitting the original sound, based on at least one of original sound information corresponding to the original sound to be emitted and sound collection information corresponding to the sound collected by a sound collection means MC that collects the sound of the space into which the original sound is emitted.

[0014] Then, when it is determined that the update process is to be performed, the update means 2 updates the adjustment value, and causes the sound emission means SP to emit the original sound corresponding to the original sound information whose frequency characteristics have been adjusted using the updated adjustment value.

[0015] As described above, according to the operation of the sound control device S of the embodiment, a determination is made based on at least one of the original sound information and the sound collection information as to whether or not to perform an update process for updating the adjustment value used to adjust the frequency characteristics of the original sound information when emitting the original sound.Therefore, based on the sound collection information, etc., the frequency characteristics of the original sound information can be appropriately adjusted and emitted while eliminating the influence of the space into which the original sound is emitted. EXAMPLES

[0016] Next, a specific example corresponding to the above-mentioned embodiment will be described with reference to Figs. 2 to 4. The example described below is an example in which the present application is applied to a sound field adjustment device that, when playing back a sound such as music from a car audio device mounted in a vehicle, sets a frequency characteristic adjustment value corresponding to the shape of the interior space of the vehicle, the number and positions of passengers, or the influence of disturbance sounds generated during travel, and adjusts the frequency characteristics of sound data corresponding to the sound to be played back according to the frequency characteristic adjustment value. In this case, examples of the disturbance sounds include road noise, wind noise, and engine noise generated during travel, and sounds caused by weather conditions such as the rain sound. The "frequency characteristic adjustment value" is an adjustment value for realizing a so-called equalizer characteristic, and specifically, an adjustment value for adjusting the sound pressure for each frequency band of the sound data. Furthermore, the interior space of the vehicle corresponds to an example of the "space" according to the present application.

[0017] Fig. 2 is a block diagram showing the general configuration of a sound field adjustment device according to an embodiment, Fig. 3 is a flowchart showing a sound field adjustment process according to an embodiment, and Fig. 4 is a conceptual diagram explaining details of the sound field adjustment process according to an embodiment. In Fig. 2, the same component numbers as those of the respective components in the sound control device S according to the embodiment shown in Fig. 1 are used for the respective components of the embodiment.

[0018] As shown in Fig. 2, the sound field adjustment device SS according to the embodiment is connected to a smartphone SM on which sound data of the sound to be reproduced is recorded in various file formats, and the car audio device 16 connected to a speaker SP as an example of the sound emission means SP of the embodiment. A so-called music player may be connected instead of the smartphone SM. The sound field adjustment device SS according to the embodiment is composed of a microphone MC as an example of the sound collection means MC according to the embodiment, a frequency characteristic analysis unit 1 as an example of the determination means 1 according to the embodiment, an equalizer value setting unit 2 as an example of the update means 2 according to the embodiment, a communication unit 10 connected to the smartphone SM by wire or wirelessly, an audio decoder 11, an acceleration sensor 12, a frequency characteristic adjustment unit 13, an audio encoder 14, and a communication unit 15 connected to the car audio device 16 by wire or wirelessly. In this case, the frequency characteristic analysis unit 1, the equalizer value setting unit 2, the audio decoder 11, the frequency characteristic adjustment unit 13 and the audio encoder 14 may be realized in hardware by hardware logic circuits such as a CPU, a RAM (Random Access Memory) and a ROM (Read Only Memory) (not shown) provided in the sound field adjustment device SS, or may be realized in software by storing a program corresponding to a flowchart showing the sound field adjustment process according to the embodiment described later in the ROM or the like and reading and executing the program by the CPU or the like. Also, as shown by the dashed lines in Fig. 2, the frequency characteristic analysis unit 1 and the equalizer value setting unit 2 constitute an example of the sound control device S according to the embodiment. Furthermore, the frequency characteristic analysis unit 1 corresponds to an example of the "speed information acquisition means" and the "sound emission determination means" according to the present application.

[0019] In the above configuration, as described above, sound data such as music to be played is pre-recorded in the smartphone SM, and the sound data is output to the communication unit 10 of the sound field adjustment device SS by a playback start operation or the like on the smartphone SM. This music to be played corresponds to an example of the "original sound" according to the present application. As a result, the communication unit 10 performs a preset input interface process on the sound data input from the smartphone SM and outputs the sound data to the audio decoder 11. The audio decoder 11 then performs a decoding process on the output sound data based on a preset decoding method, and outputs the sound data to the frequency characteristic analysis unit 1 and the frequency characteristic adjustment unit 13 as sound data in a format capable of detecting the sound pressure for each predetermined frequency band as the frequency characteristic (for example, sound data in a PCM (Pulse Code Modulation) format).

[0020] On the other hand, the acceleration sensor 12 detects the magnitude and direction of the acceleration applied to the vehicle equipped with the sound field adjustment device SS, generates acceleration data indicating the detected acceleration, and outputs it to the frequency characteristic analysis unit 1. The acceleration data is integrated in the frequency characteristic analysis unit 1 as described later, converted into speed data indicating the speed of the vehicle, and is used for the sound field adjustment process according to the embodiment. At this time, the acceleration sensor 12 may be configured to integrate the acceleration data itself and output it to the frequency characteristic analysis unit 1 as the speed data. On the other hand, the microphone MC collects sounds in the interior space of the vehicle equipped with the sound field adjustment device SS, and outputs the collected sound data to the frequency characteristic analysis unit 1 in a format that allows detection of sound pressure for each predetermined frequency band as the frequency characteristic. The sounds collected by the microphone MC include sounds such as music emitted from the speaker SP according to the embodiment as described later, as well as the disturbance sounds when the vehicle is moving.

[0021] Next, the frequency characteristic analysis unit 1 mainly executes the frequency characteristic analysis process in the sound field adjustment process according to the embodiment based on the sound data from the audio decoder 11, the speed data corresponding to the acceleration data detected by the acceleration sensor 12, and the sound collection data from the microphone MC. At this time, if the acceleration data is output from the acceleration sensor 12, the frequency characteristic analysis unit 1 integrates it to generate the speed data and subject it to the frequency characteristic analysis process. The result of the frequency characteristic analysis process is output to the equalizer value setting unit 2. As a result, the equalizer value setting unit 2 sets a correction value in the sound field adjustment process according to the embodiment for updating the frequency characteristic adjustment value used to adjust the frequency characteristic (i.e., the sound pressure for each of the predetermined frequency bands) of the sound data emitted through the speaker SP based on the result of the frequency characteristic analysis process, and outputs it to the frequency characteristic adjustment unit 13.

[0022] On the other hand, the frequency characteristic adjustment unit 13 stores in advance in a memory (not shown) frequency characteristic data (hereinafter, the frequency characteristic data will be referred to as "type-specific frequency characteristic data") that indicates frequency characteristics as optimal sound data when sound is emitted into the vehicle interior space for each type of music to be played (for example, "rock", "classical", "pops", etc.) in accordance with the original size and shape of the vehicle interior space when the vehicle is stopped (i.e., the size and shape of the vehicle interior space when no passengers are on board and no luggage is loaded). This type-specific frequency characteristic data is, for example, frequency characteristic data corresponding to the frequency characteristic adjustment value selected or set in advance by the user for each type of music. In addition to this, a frequency characteristic adjustment value arbitrarily set by the user regardless of the type of music, the size of the vehicle, etc. may be stored in advance in the memory (not shown).

[0023] When the correction value is not output from the equalizer value setting unit 2, the frequency characteristic adjustment unit 13 adjusts the frequency characteristics of the sound data using the type-specific frequency characteristic data corresponding to the sound data output from the audio decoder 11, and outputs the sound data after the frequency characteristic adjustment to the audio encoder 14. On the other hand, when the correction value is output from the equalizer value setting unit 2, the frequency characteristic adjustment unit 13 updates the frequency characteristic adjustment value of the type-specific frequency characteristic data corresponding to the sound data output from the audio decoder 11 using the correction value from the equalizer value setting unit 2 while the output is continuing, and outputs the sound data whose frequency characteristics have been adjusted using the updated frequency characteristic adjustment value to the audio encoder 14.

[0024] Thereafter, the audio encoder 14 performs encoding processing on the sound data output from the frequency characteristic adjustment unit 13 in an encoding format corresponding to the decoding format of the decoding processing in the audio decoder 11, and outputs the encoded sound data to the communication unit 15. The communication unit 15 then performs preset output interface processing on the encoded sound data output from the audio encoder 14, and outputs the data to the car audio device 16. As a result, the car audio device 16 performs preset amplification processing and the like on the encoded sound data, and emits the sound into the vehicle interior through the speaker SP.

[0025] Next, the sound field adjustment process according to the embodiment will be described more specifically with reference to FIGS.

[0026] As shown in the corresponding flowchart in FIG. 3, the sound field adjustment process of the embodiment is started, for example, by turning on a so-called ACC (Accessory) switch of a vehicle in which the sound field adjustment device SS of the embodiment is installed.

[0027] When the sound field adjustment process according to the embodiment is started, first, the frequency characteristic analysis unit 1 judges whether or not sound data whose frequency characteristics should be adjusted (i.e., sound data such as music to be played at that time) has been input from the smartphone SM (step S1). More specifically, the frequency characteristic analysis unit 1 detects, for example, the operation content on the smartphone SM or the selection operation of a playback target on the car audio device 16, and judges whether or not the sound data to be played has been input to the frequency characteristic analysis unit 1 based on the detection result. In the judgment of step S1, if the sound data to be played has not been input to the frequency characteristic analysis unit 1 (step S1: NO), the frequency characteristic analysis unit 1 proceeds to step S9 described later. This step S1 prevents the sound field adjustment process according to the embodiment from being applied to sound data whose frequency characteristics are not to be adjusted (for example, when the car audio device 16 selects to play sound data received via radio broadcast).

[0028] On the other hand, if the sound data to be reproduced is input to the frequency characteristic analysis unit 1 in the judgment of step S1 (step S1: YES), the frequency characteristic analysis unit 1 then analyzes the frequency characteristics of the input sound data and temporarily stores the analysis result in, for example, the RAM (step S2). Then, the frequency characteristic analysis unit 1 judges whether the frequency characteristics analyzed in step S2 are appropriate for performing the sound field adjustment processing according to the embodiment (step S3). Specifically, in this step S3, for example, the frequency characteristic analysis unit 1 judges whether the frequency characteristics analyzed in step S2 are equal to or higher than a preset sound pressure threshold over the entire audible frequency band, and judges that the frequency characteristics are appropriate if the frequency characteristics are equal to or higher than the sound pressure threshold over the entire band. Alternatively, the frequency characteristic analysis unit 1 judges whether the frequency characteristics analyzed in step S2 are biased in a specific frequency band, and judges that the frequency characteristics are appropriate if there is no bias.

[0029] If it is determined in step S3 that the frequency characteristics analyzed in step S2 are not appropriate for performing the sound field adjustment process according to the embodiment (step S3: NO), the frequency characteristic analysis unit 1 proceeds to step S9 described below. On the other hand, if it is determined in step S3 that the frequency characteristics analyzed in step S2 are appropriate for performing the sound field adjustment process according to the embodiment (step S3: YES), the frequency characteristic analysis unit 1 next acquires the above-mentioned sound collection data from the microphone MC (step S4), and further calculates a correlation coefficient γ between the frequency characteristics of the acquired sound collection data and the frequency characteristics of the above-mentioned sound data (step S5).

[0030] Here, the correlation coefficient γ calculated in step S5 is the correlation coefficient γ expressed by the following formula (1), for example, when the sound pressure as the frequency characteristic of the sound data in each target frequency band is defined as "parameter x" and the sound pressure as the frequency characteristic of the sound collection data in each target frequency band is defined as "parameter y." In the following formula (1), "Sxy" is the covariance of parameter x and parameter y, "Sx" is the standard deviation of parameter x, and "Sy" is the standard deviation of parameter y. Furthermore, "n" is the total number of pairs of parameter x and parameter y for the same frequency band (i.e., the number of divided frequency bands), "xi" is the individual sound pressure as parameter x, and "yi" is the individual sound pressure as parameter y, TIFF2025026751000002.tif67 is the average value of parameter x, TIFF2025026751000003.tif67 is the average value of parameter y.

[0031]

number

[0032] Here, the correlation coefficient γ defined in the above formula (1) is described in detail in, for example, the URL "https: / / sci-pursuit.com / math / statistics / correlation-coefficient.html" on the Internet. When the correlation coefficient γ is equal to or greater than a preset correlation threshold, it means that there is a correlation between the parameter x (i.e., sound pressure as the frequency characteristic of the sound data) and the parameter y (i.e., sound pressure as the frequency characteristic of the sound collection data). When this is applied to the sound field adjustment process according to the embodiment, the existence of the correlation means that the sound collection data "has a volume suitable for the sound field adjustment process according to the embodiment" and "the noise such as the disturbance sound is not so large as to impede the sound field adjustment process."

[0033] Therefore, the frequency characteristic analysis unit 1 judges whether the correlation coefficient γ calculated in step S5 is equal to or greater than the correlation threshold (step S6). If the calculated correlation coefficient γ is less than the correlation threshold in the judgment of step S6 (step S6: NO), the frequency characteristic analysis unit 1 proceeds to step S9 described later. On the other hand, if the calculated correlation coefficient γ is equal to or greater than the correlation threshold in the judgment of step S6 (step S6: YES), the frequency characteristic analysis unit 1 next judges whether the acceleration detected by the acceleration sensor 12 or the speed corresponding to the acceleration is equal to or greater than a preset speed threshold (step S7). Here, as a specific example of the speed threshold, for example, when the sound field adjustment process according to the embodiment is performed in a state in which the vehicle equipped with the sound field adjustment device SS according to the embodiment is not running, the speed threshold is set to, for example, 5 kilometers per hour. Also, when the sound field adjustment process according to the embodiment is performed in a state in which the vehicle is running at a low speed and there is little disturbance sound such as road noise, the speed threshold is set to, for example, 30 kilometers per hour. When the acceleration data is output from the acceleration sensor 12, the frequency characteristic analysis unit 1 integrates the acceleration data and uses it for the judgment in step S7, and when the speed data obtained by integrating the acceleration data is output from the acceleration sensor 12, the speed data is used as it is for the judgment in step S7. This step S7 is a judgment for not performing the sound field adjustment process according to the embodiment, since it is predicted that the disturbance sound is large when the speed of the vehicle on which the sound field adjustment device SS is mounted is greater than the speed threshold. When the speed of the vehicle is greater than the speed threshold in the judgment in step S7 (step S7: NO), the frequency characteristic analysis unit 1 proceeds to step S9 described later. On the other hand, when the speed of the vehicle is equal to or less than the speed threshold in the judgment in step S7 (step S7: YES), the frequency characteristic analysis unit 1 outputs the frequency characteristic data of the sound data and the sound collection data to the equalizer value setting unit 2.

[0034] Next, assuming that all of the conditions for performing the sound field adjustment processing of the embodiment (see steps S1, S3, S6 and S7) are met, the equalizer value setting unit 2 calculates the correction value for updating the frequency characteristic adjustment value of the type-specific frequency characteristic data corresponding to the sound data output from the audio decoder 11 (step S8).

[0035] Here, the calculation of the correction value in step S8 will be specifically described with reference to Fig. 4. First, in the above step S7, frequency characteristic data as sound data (see step S2) having the frequency characteristic shown in Fig. 4 and frequency characteristic data as collected sound data having the frequency characteristic shown in Fig. 4 are output. Here, the frequency characteristic of the collected sound data reflects the frequency characteristic of the original sound data itself, the original frequency characteristic of the in-vehicle space in which the sound corresponding to the sound data is emitted (i.e., the frequency characteristic corresponding to the size and shape of the in-vehicle space in a state where the vehicle is stopped, no passengers are on board, and no luggage is loaded), and the frequency characteristic of the in-vehicle space when the sound corresponding to the sound data is actually emitted (i.e., the frequency characteristic of the in-vehicle space in a state where a passenger is on board, luggage is loaded, and the above-mentioned disturbance sound is present). Therefore, in step S8, the equalizer value setting unit 2 subtracts the frequency characteristics of the sound data from the frequency characteristics of the collected sound data for each of the predetermined frequency bands, and calculates difference data as a result of the subtraction process (see the bottom of FIG. 4). In the bottom of FIG. 4, the upper differences for each frequency band are indicated by dashed lines, and the frequencies where the difference is zero are indicated by dashed arrows. The frequency characteristics corresponding to this difference data reflect at least three factors: the frequency characteristics indicated by the type-specific frequency characteristic data (hereinafter referred to as "sound emission type-specific frequency characteristic data") used when the sound data of the frequency characteristics shown in the top of FIG. 4 is emitted, the original frequency characteristics of the vehicle interior space, and the frequency characteristics of the vehicle interior space when the sound corresponding to the sound data is actually emitted. After that, the equalizer value setting unit 2 calculates the correction value for updating the frequency characteristic adjustment value of the sound emission type-specific frequency characteristic data so that the frequency characteristics as the difference data become the frequency characteristics indicated by the sound emission type-specific frequency characteristic data.More specifically, for example, when the type corresponding to the type-specific frequency characteristic data (i.e., the above-mentioned sound emission type-specific frequency characteristic data) set at that time is "lock", the equalizer value setting unit 2 calculates the above-mentioned correction value for update so that the frequency characteristic as the difference data shown in the lower part of FIG. 4 becomes the frequency characteristic indicated by the frequency characteristic adjustment value of the type-specific frequency characteristic data for lock. By correcting the sound emission type-specific frequency characteristic data by updating using this correction value for update, it is possible to eliminate the influence of the frequency characteristic as the vehicle interior space when the sound corresponding to the above-mentioned sound data is actually emitted (i.e., the original frequency characteristic of the above-mentioned vehicle interior space and the frequency characteristic as the vehicle interior space when the sound corresponding to the above-mentioned sound data is actually emitted). Then, the equalizer value setting unit 2 outputs the calculated correction value to the frequency characteristic adjustment unit 13.

[0036] As a result, as described above, when the correction value is not output from the equalizer value setting unit 2 (FIG. 3 step S1: NO, step S3: NO, step S6: NO, or step S7: NO), the frequency characteristic adjustment unit 13 adjusts the frequency characteristics of the sound data using the type-specific frequency characteristic data corresponding to the sound data output from the audio decoder 11 (i.e., the original type-specific frequency characteristic data without updating the frequency characteristic adjustment value), and outputs the sound data after the frequency characteristic adjustment to the audio encoder 14 (step S9). On the other hand, when the update correction value is output from the equalizer value setting unit 2, while the output is continuing, the frequency characteristic adjustment unit 13 updates the frequency characteristic adjustment value of the type-specific frequency characteristic data using the correction value from the equalizer value setting unit 2, and outputs the sound data whose frequency characteristics have been adjusted using the updated correction value to the audio encoder 14 (step S9).

[0037] Thereafter, the sound field control device SS judges whether or not to end the sound field adjustment process according to the embodiment by, for example, detecting that the ACC switch of the vehicle in which the sound field control device SS according to the embodiment is mounted has been turned off (step S10). If the sound field adjustment process according to the embodiment is to be continued in the judgment of step S10 (step S10: NO), the sound field control device SS returns to the above step S1 and repeats the above-described process. On the other hand, if the sound field adjustment process according to the embodiment is to be ended in the judgment of step S10 (step S10: YES), the sound field control device SS ends the sound field adjustment process as it is.

[0038] As described above, according to the sound field adjustment process of the embodiment, based on at least one of the sound data of the sound emitted into the vehicle interior space and the collected sound data, it is determined whether or not to update the adjustment value used to adjust the frequency characteristics of the sound data when emitting the sound (see steps S8 and S9 in FIG. 3) (see steps S1, S3, S6, and S7 in FIG. 3), so that the frequency characteristics of the sound data can be appropriately adjusted and emitted while eliminating the influence of the vehicle interior space based on the collected sound data, etc. Note that, according to the sound field adjustment process of the embodiment, as a result, it is possible to eliminate not only the influence of the vehicle interior space, but also the influence on the frequency characteristics of the acoustic circuit itself and the structure of the speaker SP included in the car audio device 16, for example.

[0039] In addition, since the above-mentioned update is a process of updating the frequency characteristic adjustment value corresponding to the original type-specific frequency characteristic data so that the frequency characteristics of the sound collection data become the frequency characteristics indicated by the type-specific frequency characteristic data, the adjustment can be performed more appropriately based on the frequency characteristics of the sound collection data, etc.

[0040] Furthermore, since the type-specific frequency characteristic data is frequency characteristic data of frequency characteristics selected or set by the user, it is possible to adjust the frequency characteristics appropriately in accordance with the preferences of the user.

[0041] Furthermore, the above update is performed when the frequency characteristics of the sound data are appropriate in the audible frequency band (in other words, when the frequency band is above a predetermined sound pressure threshold; see step S3 in Figure 3), thereby allowing the frequency characteristics to be adjusted more appropriately.

[0042] In addition, since it is determined whether or not to perform the above-mentioned update based on the correlation coefficient γ corresponding to the similarity between the frequency characteristics of the sound collection data and the frequency characteristics of the sound data (see steps S5 and S6 in FIG. 3), it is possible to adjust the frequency characteristics more appropriately.

[0043] Furthermore, whether or not to perform the above-mentioned update is determined based on the sound collection data acquired when the speed of movement within the vehicle interior space where the sound is emitted is below a predetermined speed threshold (see step S7 in Figure 3), thereby allowing the frequency characteristics to be adjusted more appropriately.

[0044] Furthermore, since the determination as to whether or not to perform the above-mentioned update is made is made using the collected sound data acquired when it is indicated that the sound to be played (music, etc.) is being emitted into the vehicle interior (see step S1 in Figure 3), the frequency characteristics can be adjusted more appropriately.

[0045] In the above-described embodiment, the frequency characteristic adjustment value is set to be flat across the entire frequency band, and the frequency characteristic adjustment value is updated so that the difference data shown in the lower part of Figure 4 becomes zero decibels across the entire frequency band, thereby making it possible to hear the sound to be reproduced with frequency characteristics that correspond to the original sound of the sound to be reproduced.

[0046] In the above-mentioned embodiment, the significance of using the correlation coefficient γ is that it is used to determine whether the collected sound data "has a volume suitable for the sound field adjustment process according to the embodiment" and "the noise such as the disturbance sound is not loud enough to impede the sound field adjustment process." However, if the significance is limited to only "determining that the noise such as the disturbance sound is not loud enough to impede the sound field adjustment process," the determination may be made using only the acceleration data from the acceleration sensor 12 without using the correlation coefficient γ, and the acceleration sensor 12 itself may be made unnecessary by using the correlation coefficient γ to "determine that the noise such as the disturbance sound is not loud enough to impede the sound field adjustment process."

[0047] Furthermore, when a device on the speaker SP side as viewed from the sound field adjustment device SS in the embodiment (for example, the car audio device 16 in the embodiment) is capable of switching the sound source of the sound to be reproduced and the sound field adjustment device SS is unable to obtain information indicating the current sound source, there is a problem in that the sound field adjustment process in the embodiment cannot be performed appropriately when a different sound source is being reproduced. However, by using the correlation coefficient γ in the embodiment, it is also possible to determine whether the sound source of the sound to be reproduced has been switched in the device on the speaker SP side (i.e., whether the sound to be reproduced, such as music, is being reproduced).

[0048] [Variations] Next, modifications corresponding to the above-described embodiment will be described.

[0049] First, as a first modification, in the above embodiment, whether or not to update the correction value of the frequency characteristic of the sound data is determined in steps S1, S3, S6, and S7 shown in Fig. 3, but whether or not to adjust the frequency characteristic of the sound data itself may be determined in step S1, etc. Even in this case, the frequency characteristic of the sound data can be more appropriately adjusted and emitted while eliminating the influence of the interior space of the vehicle.

[0050] Next, as a second modified example, in the above embodiment, whether or not to update the adjustment value is determined by using steps S1, S3, S6, and S7 shown in Fig. 3 in combination, but in addition to this, it may be configured to determine whether or not to update the adjustment value or adjust the frequency characteristic itself based only on speed data indicating the speed of movement of the vehicle (inside the vehicle) in which the sound field adjustment device SS is installed. Even in this case, it is possible to appropriately adjust the frequency characteristic of the sound data and emit the sound while eliminating the influence of the movement of the vehicle (inside the vehicle).

[0051] As a third modified example, in the above embodiment, the frequency characteristic of the sound data before the frequency characteristic adjustment and the frequency characteristic of the collected sound data are used to determine whether or not to update the frequency characteristic adjustment value. Alternatively, the frequency characteristic after adjustment by the frequency characteristic adjustment unit 13 (i.e., the frequency characteristic of the sound data immediately after output from the frequency characteristic adjustment unit 13) and the frequency characteristic of the collected sound data may be used to determine whether or not to update the frequency characteristic adjustment value or adjust the frequency characteristic itself. This is because the frequency characteristic after adjustment by the frequency characteristic adjustment unit 13 is also the frequency characteristic of the sound data corresponding to the sound to be emitted. According to the configuration of this third modified example, the frequency characteristic corresponding to the difference data shown in the lower part of FIG. 4 representatively reflects the original frequency characteristic of the vehicle interior space and the frequency characteristic of the vehicle interior space when the sound corresponding to the sound data is actually emitted. Therefore, by updating using the correction value according to the embodiment so that the magnitude of this difference data is reduced, the frequency characteristic of the sound emitted into the vehicle interior space can be brought closer to the desired frequency characteristic (so-called frequency characteristic as a reference).

[0052] Furthermore, as a fourth modified example, in the above-mentioned embodiment, the car audio device 16 and the smartphone SM as a sound source are connected to the sound field adjustment device SS according to the embodiment, but in addition to this, the sound field adjustment device may be configured to include a storage function of the sound source and a playback function of the corresponding sound data. In this case, the communication unit 10 and the communication unit 15 are not necessary. By configuring in this way, the embodiment can be applied to existing car audio products (more specifically, car navigation devices, audio devices that can be installed in vehicles, or players equipped with CD / DVD / BD / USB / tuners, etc.).

[0053] Furthermore, as a fifth modified example, the embodiment can be applied to a so-called smart speaker. More specifically, the car audio device 16 and the speaker SP according to the embodiment can be configured to be included in a sound field adjustment device.

[0054] As a sixth modification, in the above embodiment, the sound such as music is reproduced, but the frequency characteristic adjustment value or the correction value according to the embodiment may be set for a human voice to be reproduced. In this case, the calculation of the correlation coefficient γ may be limited to a frequency band included in the human voice.

[0055] Furthermore, as a sixth variant, in the above-described embodiment (see step S9 in Figure 3), when the frequency characteristic adjustment value is not updated), adjustment may be performed while continuing to use the previously updated frequency characteristic adjustment value, or adjustment by frequency characteristic adjustment unit 13 may not be performed at all (i.e., the function of frequency characteristic adjustment unit 13 is turned off, and the sound data output from audio decoder 11 is output as is to audio encoder 14 (i.e., passed through)).

[0056] Furthermore, a program corresponding to the flowchart shown in FIG. 3 can be recorded on a recording medium such as an optical disk or a hard disk, or obtained via a network such as the Internet, and then read out and executed by a general-purpose microcomputer or the like, thereby causing the microcomputer to function as the above-mentioned CPU of the sound field control device SS of the embodiment. [Explanation of symbols]

[0057] 1. Determination means (frequency characteristic analysis section) 2. Update means (equalizer value setting unit) 13 Frequency response adjustment section 16 Car audio equipment S Sound control device SS sound field adjustment device SP Sound emission means (speaker) MC Sound collection means (microphone) SM Smartphone

Claims

[Claim 1] a determination means for determining whether or not to perform an update process for updating an adjustment value used to adjust the frequency characteristics of the original sound information when emitting the original sound, based on at least one of original sound information corresponding to the original sound to be emitted and sound collection information corresponding to the sound collected by a sound collection means that collects sound in a space in which the original sound is to be emitted; an updating means for updating the adjustment value when it is determined that the updating process is to be performed, and for emitting from a sound emitting means the original sound corresponding to the original sound information whose frequency characteristics have been adjusted using the updated adjustment value; A sound control device comprising:

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