JP6186470B2 - Acoustic device, volume control method, volume control program, and recording medium - Google Patents

Description

  The present application relates to a technical field of a method for correcting an output sound volume in an acoustic device in a moving body such as an automobile.

  When a user who rides on a moving body listens to sound such as music using an audio device, the user generates, for example, road noise, engine sound, etc. in addition to the sound output from the speaker of the audio device I hear noise. Therefore, when the noise volume increases, it becomes difficult for the user to listen to the sound from the sound device. Therefore, conventionally, a technique for correcting the output volume of the acoustic device is known as a countermeasure against such noise.

  For example, Patent Document 1 describes a technique in which a sound correction level is determined in accordance with a sound level detected from a sound signal from a car audio and a vehicle speed, and the correction level is decreased as the sound level increases. Further, Patent Document 1 describes that a volume volume value adjusted by a volume control unit or the like may be used as the tone level instead of the tone level of the actual tone signal.

JP 2004-228937 A

  By the way, when the correction level of the sound volume is determined according to the sound level of the sound to be heard by the user as in the technique described in Patent Literature 1, the sound volume is set so that the user can easily listen to the sound even if the original sound volume is small. Can be corrected. However, the change in sound volume actually heard by the user tends to be poor. Therefore, it is difficult to reproduce the original sound volume change.

  On the other hand, when the volume correction level is determined according to the amplification level set by the user by volume operation, etc., the correction level is determined regardless of the size of the original sound volume. can do. However, when the original sound volume is low and the noise volume is high, it is difficult for the user to listen to the sound.

  As described above, when the sound correction level is determined using only one of the sound level of the sound and the amplification level set by the user, the balance between the ease of listening to the sound and the reproducibility of the change in the original sound volume. It is difficult to take

  The present application has been made in view of the above points, and an example of the problem is a volume corresponding to noise generated in a moving body while balancing the ease of listening to the sound and the change in the original volume of the sound. An object of the present invention is to provide an audio device, a sound volume control method, a sound volume control program, and a recording medium that enable correction.

  In order to solve the above-described problem, in one aspect of the present application, a control unit that controls a correction amount determined based on a noise level around a moving body, and a correction unit that corrects an output volume with the controlled correction amount. The control unit includes the sound level or the sound level so that the range that can be taken by the sound level of the sound signal output from the sound source matches the range that can be taken by the amplification level specified by the operation unit. It is an acoustic device that controls at least one of the amplification levels and controls the correction amount based on adding the acoustic level corresponding to the conversion and the amplification level.

  In another aspect of the present application, there is provided a volume control method for controlling a volume output from an acoustic device, a control step of controlling a correction amount determined based on a noise level around a moving body, and the controlled correction amount. And a correction step of correcting the output sound volume in the control step, wherein the control step matches the range that the acoustic level of the acoustic signal output from the sound source can take and the range that the amplification level specified by the operation unit can take Thus, it is a volume control method for performing the conversion of at least one of the acoustic level or the amplification level, and controlling the correction amount based on adding the acoustic level corresponding to the conversion and the amplification level. It is characterized by that.

  In still another aspect of the present application, the volume control method is a volume control program that is executed by a computer.

  In still another aspect of the present application, the present invention is a computer-readable recording medium storing the volume control program.

It is a block diagram which shows an example of schematic structure of the car audio apparatus S which concerns on one Embodiment. It is a graph which shows an example of the correction level with respect to a frequency. It is a figure which shows an example of conversion of a sound level, and calculation of a user setting volume value.

  Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. In addition, embodiment described below is embodiment at the time of applying this application with respect to the car audio apparatus mounted in a motor vehicle.

[1. Configuration of Car Audio Device S]
First, the configuration of the car audio apparatus S according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a block diagram showing an example of a schematic configuration of a car audio apparatus S according to the present embodiment.

  As shown in FIG. 1, the car audio apparatus S includes a sound source unit 1, an equalizer 2, an electronic volume 3, a fader 4, an operation unit 5, a storage unit 6, an acoustic correction unit 7, an amplifier 8, a speaker 9, a microphone 10, noise A level detection unit 11, a stabilization processing unit 12, a correction step determination unit 13, a user volume calculation unit 14, an acoustic level detection unit 15, an acoustic level conversion unit 16, a correction volume calculation unit 17, and a correction step correction unit 18 are provided. . Here, the correction step determination unit 13 is an example of a noise acquisition unit of the present application. The acoustic correction unit 7 is an example of a correction unit of the present application. The sound level conversion unit 16, the correction volume calculation unit 17, and the correction step correction unit 18 are examples of the control unit of the present application. The operation unit 5 is an example of the operation unit of the present application.

  The sound source unit 1 is a sound source that outputs an acoustic signal corresponding to the sound to be heard by the user. The sound source unit 1 includes, for example, an optical disc player, a radio tuner, a television tuner, and the like. The equalizer 2 adjusts the frequency characteristic of the acoustic signal output from the sound source unit 1. Specifically, the equalizer 2 adjusts the signal level of the acoustic signal for each frequency in accordance with a setting made by a passenger's operation on the operation unit 5. The electronic volume 3 adjusts the signal level of the acoustic signal whose frequency characteristics are adjusted by the equalizer 2 according to the volume value (amplification level) set according to the operation of the passenger on the operation unit 5. The fader 4 adjusts the signal level of the acoustic signal output from the electronic volume 3 for each channel in accordance with a setting operation such as a left / right balance by the passenger with respect to the operation unit 5. The operation unit 5 is used to perform various operations on the car audio device S. The operation unit 5 includes, for example, buttons, knobs, touch panels, and the like.

  The storage unit 6 is a non-volatile memory such as a ROM (Read Only Memory) or an EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 6 stores various data used for controlling the car audio device S. The values of various data stored in the storage unit 6 are determined by the designer of the car audio device S, for example.

  The acoustic correction unit 7 corrects the acoustic signal output from the fader 4 as a countermeasure against noise generated by driving the automobile. Specifically, the acoustic correction unit 7 adjusts the signal level of the acoustic signal for each frequency at a correction level corresponding to the correction step value output from the correction step correction unit 18. FIG. 2 is a graph showing an example of a correction level with respect to frequency at each correction step value. As shown in FIG. 2, the higher the correction step value, the higher the correction level. That is, the higher the correction step value, the more the acoustic signal is amplified. Also, the minimum and maximum correction step values are 0 and 10. Therefore, the number of steps is 11. When the correction step value is 0, the correction level is 0 dB in the entire area. The number of steps may be other than 11.

  The storage unit 6 stores a correction amount determination table indicating the correspondence between the frequency and the correction level for each correction step value. The acoustic correction unit 7 acquires a correction level for each frequency from the correction amount determination table corresponding to the correction step value. Then, the acoustic correction unit 7 performs correction at the acquired correction level. In FIG. 2, the correction level increases as the frequency decreases. That is, the bass is amplified. However, the acoustic correction unit 7 may be configured to perform, for example, high-frequency correction or whole-area correction.

  The amplifier 8 amplifies the acoustic signal corrected by the acoustic correction unit 7. The speaker 9 outputs the acoustic signal amplified by the amplifier 8 as a sound wave. The microphone 10 collects sound including noise around the automobile such as road noise and engine sound that accompanies traveling of the automobile, and outputs the collected sound as a microphone sound signal. The noise level detector 11 detects the signal level of the microphone sound signal output from the microphone 10 and outputs the detected signal level as a noise level. The stabilization processing unit 12 performs stabilization processing such as smoothing and delaying on the noise level signal output from the noise level detection unit 11.

  The correction step determination unit 13 determines a correction step value corresponding to noise generated in the automobile. Specifically, the correction step determination unit 13 determines a higher correction step value as the noise level is higher, based on the noise level that has been stabilized by the stabilization processing unit 12. Then, the correction step determination unit 13 outputs the determined correction step value. Note that the information used to determine the correction step value by the correction step determination unit 13 is not limited to the actual noise volume. The correction step determination unit 13 may determine the correction step value using information related to noise generated in the automobile. For example, the correction step determination unit 13 may use the vehicle speed or information indicating the open / closed state of the window of the automobile. Moreover, the correction step determination unit 13 may use a plurality of pieces of information.

  The user volume calculation unit 14 calculates the amplification level set by the user. Specifically, the user volume calculation unit 14 determines the frequency adjustment level set for the equalizer 2, the amplification level set for the electronic volume, and the adjustment level for each channel set for the electronic volume 3. Are combined to calculate the final amplification level set by the user. Then, the user volume calculation unit 14 outputs the calculated amplification level as a user set volume value. The sound level detection unit 15 detects the signal level of the sound signal output from the sound source unit 1. And the sound level detection part 15 outputs the detected signal level as a sound level.

  The sound level conversion unit 16 converts the sound level output from the sound level detection unit 15 so that it can be easily compared with the user set volume value output from the user volume calculation unit 14. The car audio device S corrects the sound correction level determined in accordance with the noise generated in the car according to the sound volume. The reason is that in order to make it easier for the user to listen to the sound, it is necessary to correct the sound so that the sound is amplified as the sound volume decreases. On the other hand, when the sound volume is high, the amplification level may be reduced or may not be amplified. However, if correction is performed based only on the original sound volume, the sound is easy to hear, but the reproducibility of the change in the original sound volume is reduced. On the other hand, if the correction is performed based only on the volume value set by the user, the reproducibility of the change in the original sound volume becomes high, but the sound becomes difficult to hear when the sound volume is low. Therefore, it becomes a problem to balance the ease of listening to the sound with the reproducibility of the change in the original sound volume. Therefore, the sound level conversion unit 16, the correction volume calculation unit 17, and the correction step correction unit 18 are configured to adjust the sound level of the sound signal output from the sound source unit 1 and the user set volume value specified by the operation unit 5. Based on this, the correction amount by the acoustic correction unit 7 is controlled. In order to balance the reproducibility of the change in the original sound volume, first, it is preferable to convert the original sound volume and the volume value set by the user so that they can be easily compared with each other. The sound level represents the original sound volume. On the other hand, the user set volume value represents a volume value set by the user. In designing an audio device, the range of the signal level of an acoustic signal that can be output from a sound source generally does not match the range of volume values that can be set by the user. Therefore, in order to enable comparison, the sound level conversion unit 16 sets the sound level or the user set volume value so that the range that the sound level can take and the range that the user set volume value can take are in a predetermined relationship. Convert at least one of In the present embodiment, the sound level is converted.

  Specifically, the sound level conversion unit 16 converts the detected sound level so that the range that the converted sound level can take matches the range that the user-set volume value can take. That is, the sound level conversion unit 16 performs scale conversion of the sound level. Here, it is assumed that the sound level before conversion is So. Further, the maximum value and the minimum value of the sound level of the sound signal that can be output from the sound source unit 1 are Smax and Smin. Further, the maximum value and the minimum value of the user setting volume value that can be set by the user operation are Umax and Umin. In this case, the converted sound level Sd is calculated by the following equation.

S1 = So-Smin Formula 1
S2 = S1 × (Umax−Umin) / (Smax−Smin) Equation 2
Sd = S2 + Umin Formula 3
That is, the sound level when the minimum value is 0 is calculated by the sound level shift according to Equation 1. Next, according to Equation 2, the sound level is expanded and contracted so that the sound level scale (the difference between the maximum value and the minimum value) matches the scale of the user-set volume value. Then, the sound level when the minimum value is Umin is calculated by the sound level shift according to Equation 3. Note that, depending on the maximum value and the minimum value of the sound level and the user-set volume value, it does not mean that all of the equations 1 to S3 must be calculated. For example, if the sound level scale and the user-set volume value scale are the same, only Equation 1 and Equation 3 need be calculated. In this case, S2 = S1. Further, for example, if the minimum value of the sound level is the same as the minimum value of the user setting volume value, only Expression 2 may be calculated. In this case, S1 = So and Sd = S2.

  The correction volume calculation unit 17 calculates a volume value (sound level) used for correcting the correction step value determined by the correction step determination unit 13. This volume value is referred to as a correction volume value. Specifically, the correction volume calculation unit 17 calculates the correction volume value by adding the sound level converted by the sound level conversion unit 16 and the user setting volume value calculated by the user volume calculation unit 14. To do. Thus, the correction volume calculation unit 17 balances the ease of listening to the sound with the reproducibility of the change in the original sound volume. In order to make it possible to set whether and how much importance is given to the ease of listening to the sound and the reproducibility of the change in the original sound volume, the storage unit 6 stores the sound level and the user-set volume value. The weighting factors C1 and C2 for each are stored. Therefore, the correction volume calculation unit 17 calculates the following equation using the weighting coefficient.

Correction volume value =
C1 × conversion acoustic level + C2 × user set volume value Equation 4
The designer can arbitrarily set each weighting factor. For example, the designer may set within a range of 0 to 1 so as to satisfy C1 + C2 = 1. For example, if both the ease of listening to the sound and the reproducibility of the change in the original volume of the sound are regarded as equally important, C1 = C2 may be set. In this case, a weighting factor is not necessary. The correction volume calculation unit 17 may simply add the converted sound level and the user set volume value. In addition, if importance is placed on the ease of listening to the sound, C1> C2 may be satisfied. If importance is attached to the reproducibility of the change in the original sound volume, C1 <C2. The noise level used by the correction step correction unit 18 to determine the correction step value is a noise level that has been subjected to stabilization processing by the stabilization processing unit 12. The change in the noise level that has been subjected to the stabilization process is delayed with respect to the change in the volume of the noise that actually occurs. Therefore, when the acoustic correction is performed using the determined correction step value, the acoustic correction is performed with a delay from the actual change in the noise volume.

  Further, the sound level detection unit 15 may stabilize the sound signal from the sound source unit 1 and detect the level of the sound signal. In such a case, for example, when the original sound volume changes so as to increase suddenly from a substantially silent state, the correction is delayed, so that the sound correction is performed based on a large correction step value. A loud sound may be instantaneously output from the speaker 9. When it is desired to avoid such a situation, C1 <C2 may be set with emphasis on the reproducibility of the change in the original sound volume.

  A specific example of sound level conversion by the sound level conversion unit 16 and calculation of a user-set volume value by the correction volume calculation unit 17 will be described below. FIG. 3 is a diagram illustrating an example of sound level conversion and user-set volume value calculation. As shown in FIG. 3, the maximum value and the minimum value of the sound level are 50 dB and 0 dB. On the other hand, the maximum value and the minimum value of the user set volume value are 0 dB and −100 dB. Here, it is assumed that 30 dB is detected as the sound level. Further, it is assumed that the user setting volume value is −20 dB. Also assume that C1 = C2 = 0.5. In this case, the acoustic level conversion unit 16 converts the acoustic level of 30 dB into −40 dB. Then, the correction volume calculation unit 17 calculates −30 dB as the correction volume value. When C1 = C2 = 0.5, the correction volume value is an average value of the sound level and the user set volume value.

  In contrast, for example, it is assumed that the sound level and the user-set volume value are simply added without converting the sound level. In this case, 30 dB-20 dB = 10 dB. This value of 10 dB is considered to correspond to the sound level when the sound level is detected from the sound signal output from the fader 4. In other words, this is a result of the original sound volume being adjusted by user settings. If C1 = C2 = 0.5 is added, 5 dB is obtained. However, this value is not an average value of the sound level and the user set volume value. The reason is that the range of the sound level is different from the range of the user set volume value in the first place. This makes it impossible to balance the ease of listening to the sound with the reproducibility of the change in the original sound volume. Balance can be achieved by scale conversion by the sound level converter 16.

  The correction step correction unit 18 corrects the correction volume value determined by the correction step determination unit 13 based on the correction volume value calculated by the correction volume calculation unit 17. Specifically, the correction step correction unit 18 determines the correction coefficient C3 based on the correction volume value, and calculates the following equation.

Correction step value after correction = C3 × correction step value before correction Expression 5
The storage unit 6 stores a correction coefficient determination table that indicates the correspondence between the correction volume value and the correction coefficient. Specifically, in the correction coefficient determination table, for each correction volume value, a correction volume value and a correction coefficient C3 are set in association with each other. The correction step correction unit 18 determines the correction coefficient C3 with reference to the correction coefficient determination table. The correction coefficient C3 is set within a range of 0 to 1, for example. The setting content of the correction coefficient C3 is arbitrary, but basically, the correction coefficient C3 is set to be larger as the correction volume value is smaller. That is, the smaller the correction volume value, the higher the amplification level of the acoustic signal.

  Note that the correction step correction unit 18 may set C3 using a predetermined function using the correction volume value as a parameter.

[2. Operation of car audio device S]
Next, the operation of the car audio apparatus S according to the present embodiment will be described.

  The sound level conversion unit 16 converts the sound level output from the sound level detection unit 15. Specifically, the sound level conversion unit 16 calculates the sound level after conversion using Equations 1 to 3. Then, the sound level conversion unit 16 outputs the calculated sound level to the correction volume calculation unit 17.

  The correction volume calculation unit 17 calculates a correction volume value. Specifically, the correction volume calculation unit 17 includes the sound level output from the sound level conversion unit 16, the user set volume value output from the user volume calculation unit 14, and the weighting factors C <b> 1 and C <b> 2 stored in the storage unit 6. Is used to calculate Equation 4. Then, the correction volume calculation unit 17 outputs the calculated correction volume value to the correction step correction unit 18.

  The correction step correction unit 18 corrects the correction step value determined by the correction step determination unit 13 based on the correction volume value. Specifically, the correction step correction unit 18 acquires the correction coefficient C3 corresponding to the correction volume value from the correction coefficient determination table stored in the storage unit 6. Next, the correction step correction unit 18 calculates Equation 5. Then, the correction step correction unit 18 outputs the corrected correction step value to the acoustic correction unit 7.

  The sound correction unit 7 corrects the sound according to the correction step value corrected by the correction step correction unit 18. Specifically, the acoustic correction unit 7 performs correction for each frequency from the correction amount determination table corresponding to the correction step value output from the correction step correction unit 18 among the correction amount determination tables stored in the storage unit 6. Get the level. Then, the sound correction unit 7 corrects the sound signal output from the fader 4 with the correction level acquired for each frequency. Each unit repeats the processing described above.

  As described above, according to the present embodiment, the correction step determination unit 13 acquires the detected noise level around the automobile detected by the noise level detection unit 11, and the acoustic correction unit 7 acquires the detected detection. The output volume is corrected based on the noise level, and the sound level conversion unit 16, the correction volume calculation unit 17 and the correction step correction unit 18 specify the sound level of the sound signal output from the sound source unit 1 and the operation unit 5. The correction amount by the sound correction unit 7 is controlled based on the user set volume value. Therefore, it is possible to perform acoustic correction corresponding to noise generated in the automobile while balancing the ease of listening to the sound and the change in the original sound volume.

  In addition, the sound level conversion unit 16 converts at least one of the sound level and the user-set volume value so that the range that can be taken by the level of the sound signal and the range that can be taken by the user-set volume value have a predetermined relationship. The correction volume calculation unit 17 adds the one converted by the sound level conversion unit 16 and the other, so that the correction step correction unit 18 determines the correction amount by the sound correction unit 7. Therefore, it is possible to perform acoustic correction corresponding to noise generated in the automobile while balancing the ease of listening to the sound and the change in the original sound volume.

  Further, the correction volume calculation unit 17 weights one and the other converted by the sound level conversion unit 16 with a weighting factor set in advance for each of the sound level and the user set volume value. Add together. Therefore, by setting the weighting factor in advance, the designer can arbitrarily determine whether and how much importance is given to the ease of listening to the sound and the change in the original sound volume. Can do.

  The car audio apparatus S includes a microprocessor such as a DSP (Digital Signal Processor), and the microprocessor reads out and executes a program stored in the storage unit 6 or the like, whereby the sound level conversion unit 16 and the correction volume calculation. The above-described processing may be performed as the unit 17 and the correction step correction unit 18. Further, the above-described program may be recorded on a recording medium such as an optical disk, and the program may be stored in the storage unit 6 from the recording medium by a disk drive device or the like.

  Moreover, in the said embodiment, the car audio apparatus S was comprised so that the direction of an acoustic level might be converted among an acoustic level and a user setting volume value. However, the car audio device S may be configured to convert the user-set volume value so that the range that the user-set volume value can take matches the range that the sound level can take. Further, the car audio device S may be configured to convert both the sound level and the user set volume value. In this case, the car audio device S converts both the sound level and the user-set volume value so that the range that can be taken by the converted sound level matches the range that can be taken by the user-set volume value after conversion. That's fine. And the car audio apparatus S should just add the converted sound level and the converted user setting volume value.

  In the above embodiment, the acoustic device of the present application is applied to a car audio device mounted on an automobile. For example, the audio device mounted on a moving body such as an airplane, a ship, a train, etc. An acoustic device may be applied.

S car audio apparatus 1 sound source unit 2 equalizer 3 electronic volume 4 fader 5 operation unit 6 storage unit 7 acoustic correction unit 8 amplifier 9 speaker 10 microphone 11 noise level detection unit 12 stabilization processing unit 13 correction step determination unit 14 user volume calculation unit 15 Sound Level Detection Unit 16 Sound Level Conversion Unit 17 Correction Volume Calculation Unit 18 Correction Step Correction Unit

Claims (7)

A control unit that controls a correction amount determined based on a noise level around the moving body;
A correction unit that corrects the output volume with the controlled correction amount,
The control unit has at least one of the acoustic level and the amplification level so that a range that can be taken by the acoustic level of the acoustic signal output from the sound source matches a range that can be taken by the amplification level specified by the operation unit. The correction amount is controlled based on adding the acoustic level corresponding to the conversion and the amplification level.
An acoustic device characterized by that. A noise acquisition unit for acquiring the noise level;
A determination unit that determines the correction amount for correcting the output volume based on the acquired noise level;
The control unit controls the correction amount determined by the determination unit;
The acoustic device according to claim 1. The control unit controls the correction amount to be smaller as the sum of the acoustic level corresponding to the conversion and the amplification level is larger.
The acoustic device according to claim 1, wherein the acoustic device is characterized. The control unit controls the correction amount based on weighting and adding each of the acoustic level and the amplification level corresponding to the conversion with a preset weight.
The acoustic device according to any one of claims 1 to 3, wherein A volume control method for controlling a volume output by an audio device,
A control process for controlling a correction amount determined based on a noise level around the moving body;
A correction step of correcting the output volume by the controlled correction amount,
In the control step, at least one of the acoustic level and the amplification level is set so that a range in which the acoustic level of the acoustic signal output from the sound source can be taken and a range in which the amplification level specified by the operation unit can be taken. The correction amount is controlled based on adding the acoustic level corresponding to the conversion and the amplification level.
A volume control method characterized by the above.   A sound volume control program that causes a sound volume control method according to claim 5 to be executed by a computer.   A computer-readable recording medium storing the volume control program according to claim 6.

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