JP2008228198A - Reproduction sound adjustment device and reproduction sound adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reproduction sound adjusting device capable of adjusting a reproduction sound so that the reproduction sound and the ambient sound can be easily distinguished without being masked by the reproduction sound.
A microphone detects an ambient sound and generates an ambient sound signal. The Fourier transform processing unit 15 obtains the frequency characteristics of the ambient sound signal by performing Fourier transform on the generated ambient sound signal. Based on the frequency characteristics of the acquired ambient sound signal, the frequency band specifying unit 16 selects at least one of the predetermined n frequency bands BW1 to BWn as a target frequency band related to the characteristics of the ambient sound. Specify as BWk. The correction parameter setting unit 17 and the multiband equalizer 11 change the gain in the specified target frequency band BWk for the audio signal reproduced as the reproduced sound so that the reproduced sound and the ambient sound can be distinguished.
[Selection] Figure 1

Description

  The present invention relates to a reproduction sound adjustment device and a reproduction sound adjustment method for adjusting a reproduction sound to be reproduced and output based on ambient sounds including sounds emitted in the surroundings, and in particular, a television, a DVD player, a radio, and a CD player. The present invention relates to a reproduction sound adjustment device and a reproduction sound adjustment method that are connected to an MP3 player, a telephone, and the like and adjust reproduction sound output from these devices.

  One conventionally known adjustment device of this type adjusts the reproduced sound so that the volume from the speaker increases as the ambient noise increases (see Patent Document 1). That is, this adjustment device is reproduced by a speaker according to a microphone that collects ambient noise, a circuit that detects the steady noise level that is collected, and the detected noise level. And a circuit for changing the amplification factor of the audio signal. According to this apparatus, the larger the noise level is, the higher the amplification rate of the audio signal is set, thereby increasing the volume of the reproduced sound from the speaker. In addition, a telephone that masks ambient sounds by providing a close-contact circuit in which a pair of microphones is arranged on the front and back of the telephone and both microphone inputs are input to the differential input terminals of the differential amplifier (see Patent Document 2). There is also a proposal.

JP-A-11-261355 Japanese Patent Laid-Open No. 61-214852

  However, in the reproduction sound adjusting device according to the conventional patent document 1, when the noise is large, the sound volume from the speaker is increased. Therefore, when a sound that needs to be distinguished from the reproduction sound is emitted from the vicinity of the device, For example, even if another person in the vicinity of this device talks to a person who is listening to music played through the playback sound adjustment device, the sound emitted around the device is likely to be loud from the speaker. It may be masked by the adjusted playback sound. In addition, the sound adjustment device found in Patent Document 2 is a technique for masking ambient sounds in order to prioritize conversation and playback sounds.

  It is an object of the present invention to distinguish between sounds emitted from the surroundings and reproduced sounds without masking the sounds emitted in the surroundings without completely masking the sounds emitted in the surroundings. To provide a reproduction sound adjustment device and a reproduction sound adjustment method capable of adjusting the reproduction sound so as to be easy.

A reproduction sound adjusting device according to the present invention adjusts reproduction sound to be reproduced and output based on ambient sound, and includes ambient sound detection means, ambient sound characteristic acquisition means, frequency band specifying means, and sound adjustment. Means. The ambient sound referred to here mainly includes sounds emitted around the reproduction sound adjusting device.
The ambient sound detection means detects the ambient sound and generates an ambient sound signal, and the ambient sound characteristic acquisition means acquires the frequency characteristic of the generated ambient sound signal. The frequency band specifying means specifies at least one frequency band of a plurality of predetermined frequency bands as a target frequency band related to the characteristics of the ambient sound based on the frequency characteristics of the acquired ambient sound signal. The sound adjusting means changes the gain of the sound signal reproduced as the reproduced sound in the specified target frequency band.
In the reproduction sound adjusting apparatus, the sound adjusting unit may include a correction parameter setting unit and an equalizer. The correction parameter setting means sets a correction parameter for correcting the gain of the audio signal in the target frequency band specified by the frequency band specifying means. The equalizer increases or decreases the gain in the specified target frequency band based on the set correction parameter.
Further, (1) In the reproduction sound adjusting apparatus in which the sound adjusting means includes a correction parameter setting means and an equalizer, the frequency band specifying means may be configured as follows. That is, the frequency band specifying unit specifies a frequency band including a frequency at which the intensity of the ambient sound is maximum or minimum as the target frequency band. In addition, in this reproduction sound adjusting device, the correction parameter setting means reduces the gain of the audio signal in the target frequency band including the frequency at which the intensity of the ambient sound is maximized, and the intensity of the ambient sound is minimized. The correction parameter may be set so that the gain of the audio signal is increased in the target frequency band including the frequency.
In the reproduction sound adjusting apparatus of (1), the correction parameter setting means uses the ambient sound signal acquired by the ambient sound characteristic acquisition means as the correction parameter in the target frequency band specified by the frequency band specifying means. It may be set using the intensity of the ambient sound in the target frequency band obtained based on the frequency characteristic and the auditory characteristic value in the target frequency band obtained based on the auditory characteristic of the person specified in advance.
In addition, (2) the reproduction sound adjusting device in which the sound adjustment unit includes a correction parameter setting unit and an equalizer, a reproduction sound characteristic acquisition unit may be provided, and the frequency band specifying unit may be configured as follows. That is, the reproduction sound characteristic acquisition unit acquires the frequency characteristic of the audio signal. The frequency band specifying means, as the target frequency band, based on the frequency characteristics of the audio signal acquired by the reproduction sound characteristic acquisition means and the frequency characteristics of the ambient sound signal acquired by the ambient sound characteristics acquisition means, A frequency band including a frequency at which the difference between the intensity of the sound and the intensity of the reproduced sound by the audio signal is maximized or minimized is specified. In the reproduction sound adjusting device, the correction parameter setting means reduces the gain of the audio signal in a target frequency band including a frequency where the difference obtained by subtracting the intensity of the reproduction sound based on the audio signal from the intensity of the ambient sound is maximized. The correction parameter may be set so that the gain is increased in the target frequency band including the frequency at which the difference is minimal.
In the reproduction sound adjusting apparatus of (2), the correction parameter setting means uses the ambient sound signal acquired by the ambient sound characteristic acquisition means as the correction parameter in the target frequency band specified by the frequency band specifying means. A comparison of the intensity of ambient sound in the target frequency band obtained based on the frequency characteristics of the sound and the intensity of the reproduced sound by the audio signals in the target frequency band obtained based on the frequency characteristics of the audio signal obtained by the reproduction sound characteristic obtaining means. The characteristic comparison value obtained in this way and the auditory characteristic value in the target frequency band obtained based on the human auditory characteristic specified in advance may be used.
The reproduction sound adjustment method according to the present invention adjusts reproduction sound to be reproduced and output, and includes a detection step, a first acquisition step, a specifying step, and a change step. To do. The ambient sound referred to here mainly includes sounds emitted around the reproduction sound adjusting device.
In the detection step, the ambient sound is detected and an ambient sound signal is generated. In the first acquisition step, the frequency characteristic of the generated ambient sound signal is acquired. In the specifying step, at least one frequency band of a plurality of predetermined frequency bands is specified as a target frequency band related to the characteristics of the ambient sound based on the frequency characteristics of the acquired ambient sound signal. In the changing step, the gain of the audio signal reproduced as the reproduced sound is changed in the specified target frequency band.
This reproduction sound adjustment method may include a second acquisition step, and the specific step may be configured as follows. In the second acquisition step, the frequency characteristic of the audio signal is acquired. Based on the frequency characteristics of the audio signal acquired in the second acquisition step and the frequency characteristics of the ambient sound signal acquired in the first acquisition step in the specific step, reproduction based on the intensity of the ambient sound and the audio signal A frequency band including a frequency at which the difference from the sound intensity is maximum or minimum is specified as the target frequency band.

  According to the present invention, based on the frequency characteristics of the ambient sound, the frequency characteristics of the reproduced sound, etc., the frequency band related to the characteristics of the ambient sound is specified as the target frequency band among the predetermined frequency bands, and the reproduced sound is And the ambient sound are easily distinguished from each other, the gain in the specified target frequency band is changed with respect to the audio signal of the reproduced sound. As an example, this target frequency band is specified as a frequency band including a frequency at which the difference obtained by subtracting the intensity of the reproduced sound by the audio signal from the intensity of the ambient sound output from the microphone is maximized, and the gain of the audio signal Is changed so as to decrease the gain in the frequency band where the difference in intensity between the two sounds becomes maximum. For this reason, it is possible to avoid the inconvenience that the ambient sound is masked by the high volume reproduced sound as in the conventional apparatus, and the ambient sound that needs to be recognized cannot be heard.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 shows a first embodiment of a reproduction sound adjusting apparatus according to the present invention. The reproduction sound adjusting device 1 reproduces the adjusted reproduction sound while adjusting the reproduction sound based on the sound emitted in the surroundings. In FIG. 1, the functions of the units 11, 13, 15 to 17 excluding the speaker 12 and the microphone 14 can be realized by a program. In this case, the reproduction sound adjusting device 1 includes a microprocessor, a RAM, a ROM, and an input / output. The device includes an interface and the like. All or a part of each of the units 11, 13, 15 and the like can be configured by a digital circuit or the like.

  The multiband equalizer 11 can change the gain in each of n (n is an integer of 2 or more) frequency bands BW1 to BWn with respect to an audio signal reproduced as reproduced sound. Here, the audio signal is a digital signal having a predetermined number of bits, and a graphic equalizer is used as the multiband equalizer 11. For example, in the multiband equalizer 11, 25 Hz to 20 kHz is divided into 30 frequency bands BW1 to BW30 for each predetermined frequency, and the gain can be changed for each frequency band. A parametric equalizer may be used as the multiband equalizer 11. In the reproduction sound adjustment apparatus 1, the gain adjustment for each frequency band in the multiband equalizer 11 is performed by using the frequency characteristics of the reproduction sound (audio signal) and the surrounding including the sound emitted around the reproduction sound adjustment apparatus 1. This is automatically performed based on the frequency characteristics of the sound (ambient sound signal). The speaker 12 appropriately amplifies the audio signal whose gain in each frequency band is adjusted by the multiband equalizer 11 and outputs a reproduced sound.

  The Fourier transform processing unit 13 acquires the frequency characteristics of the sound signal by performing (discrete) Fourier transform on the sound signal that is the reproduced sound. The microphone 14 detects the ambient sound of the reproduction sound adjusting device 1 and generates an ambient sound signal, and the Fourier transform processing unit 15 performs Fourier transform on the ambient sound signal, thereby adjusting the frequency characteristics of the ambient sound signal. get. The ambient sound referred to here mainly includes a sound component emitted around, but also includes a reproduced sound component emitted from the speaker 12 after adjustment by the reproduction sound adjusting apparatus 1.

  The frequency band specifying unit 16 uses the multiband equalizer 11 based on the frequency characteristics of the audio signal acquired by the Fourier transform processing unit 13 and the frequency characteristics of the ambient sound signal acquired by the Fourier transform processing unit 15. At least one frequency band among all frequency bands BW1 to BWn in which the gain can be changed is specified as a target frequency band BWk (k is an integer from 2 to n) related to the characteristics of the ambient sound. The correction parameter setting unit 17 sets a correction parameter Pk for correcting the gain of the audio signal in the specified target frequency band BWk. Since the multiband equalizer 11 increases or decreases the gain of the audio signal by the correction parameter Pk in the target frequency band BWk, the frequency band specifying unit 16 and the multiband as these audio adjusting means are used. Due to the operation of the equalizer 11, the reproduced sound and the ambient sound can be distinguished.

  FIG. 2 is a diagram for explaining the specification of the target frequency band in the frequency band specifying unit 16 and the setting of the correction parameter in the correction parameter setting unit 17. 2A and 2B, the solid line schematically shows the intensity of the reproduced sound after the Fourier transform, and the broken line schematically shows the intensity of the ambient sound after the Fourier transform. It is assumed that the reproduced sound emitted from the speaker 12 is attenuated to some extent and included in the ambient sound. In FIG. 2B, the alternate long and short dash line indicates the intensity of the reproduced sound after the gain is adjusted. In the reproduced sound adjusting apparatus 1, as shown in FIG. 2B, the gain of the audio signal in each frequency band is adjusted by the correction parameter so that the ambient sound is separated from the reproduced sound.

  That is, the ambient sound intensity is maximum (peaks and peaks) near the frequencies fA and fC, and the ambient sound intensity is minimal (valley and peaks down) near the frequency fB. It has become. The frequency band specifying unit 16 extracts the characteristics of the ambient sound or the characteristics of the ambient sound with respect to the reproduced sound, and specifies the frequency band including the characteristic frequency as the target frequency band. Specifically, the correction parameter setting unit 17 gains the reproduced sound in the frequency band including the frequency fA and the frequency band including the frequency fC so that the characteristics of the ambient sound are separated from the reproduced sound and emphasized. The correction parameter for adjusting the gain is set so that the gain of the reproduced sound is increased in the frequency band including the frequency fB.

  In particular, in FIG. 2, the intensity of the reproduced sound is minimal in the vicinity of the frequencies fA and fC where the ambient sound intensity is maximum, and in the vicinity of the frequency fB where the ambient sound intensity is minimal. Although the intensity of the reproduced sound is maximal, the multiband equalizer 11 can separate the ambient sound and the reproduced sound even in other situations. That is, for example, the multiband equalizer 11 is also used in the situation where the intensity of the reproduced sound does not take an extreme value near the frequency at which the intensity of the ambient sound is maximized and the intensity of the reproduced sound is maximized. Can separate the ambient sound and the reproduced sound by adjusting the gain of the reproduced sound so that the difference between the ambient sound and the reproduced sound does not become excessively large.

  Details of an example of processing for specifying the target frequency band related to the characteristics of such ambient sounds will be described. FIG. 3 is a diagram for explaining this process. Here, a function representing a difference obtained by subtracting the intensity of the reproduced sound from the intensity of the ambient sound is set as a characteristic comparison function B (f) having the frequency f as an argument, and the one-dot chain line in FIG. Represents the function B (f). The characteristic comparison value by the characteristic comparison function B (f), that is, the difference obtained by subtracting the intensity of the reproduced sound from the intensity of the ambient sound is maximal at the frequencies fA1 and fC1, and is minimal at the frequency fB1. . The frequency band specifying unit 16 extracts extreme values of these characteristic comparison values. That is, the frequency band specifying unit 16 obtains a frequency at which the differential value of the difference obtained by subtracting the intensity of the reproduced sound from the intensity of the ambient sound is zero. Depending on whether the differential value of the difference changes from positive to negative or from negative to positive, it is determined whether the corresponding difference value is a maximum value or a minimum value. And the frequency band specific | specification part 16 specifies the frequency band corresponding to these extreme values. The frequency band specifying unit 16 outputs data specifying the target frequency band, data indicating the intensity of the ambient sound, data indicating the intensity of the reproduced sound, and the like to the correction parameter setting unit 17 for the specified target frequency band. .

  The correction parameter setting unit 17 sets, as the correction parameter PA1, the gain of the reproduced sound to be reduced in the target frequency band including the frequency fA1 at which the characteristic comparison value is maximum, and the target frequency including the frequency fC1 at which the characteristic comparison value is maximum. The gain of the playback sound to be reduced in the band is set as the correction parameter PC1. Further, the gain of the reproduced sound to be increased in the target frequency band including the frequency fB1 at which the characteristic comparison value is minimized is set as the correction parameter PB1. The correction parameter can be set based on the center frequency of the target frequency band whose gain is to be increased / decreased, the intensity of the ambient sound, and the intensity of the reproduced sound.

  More specifically, the correction parameter setting unit 17 calculates a correction function G (f) using the frequency (or the center frequency of each of the frequency bands BW1 to BWn) f as an argument based on the following equation (1). Any one of the correction parameters Pk in the frequency bands BW1 to BWn corresponding to the frequency f may be set by the correction function G (f).

ここで、kはゲイン調整の基準とする所定の定数である。関数A(f)及び関数B(f)は、それぞれ、所定のテーブル上にてfとの対応関係が記述されている。補正パラメータ設定部１７は、適宜これらのテーブルを参照して補正関数G(f)を算出する。

Here, k is a predetermined constant used as a reference for gain adjustment. The function A (f) and the function B (f) each have a correspondence relationship with f on a predetermined table. The correction parameter setting unit 17 calculates the correction function G (f) with reference to these tables as appropriate.

  The function A (f) is an auditory characteristic function determined in consideration of human auditory characteristics. That is, the auditory characteristic function A (f) is adjusted according to human hearing characteristics in the low frequency region, the medium frequency region, and the high frequency region by experiment or simulation. The argument of this auditory characteristic function A uses the absolute value Df of the difference between the intensity of the ambient sound and the intensity of the reproduced sound in addition to the frequency, so that the ambient sound is less likely to be masked by the reproduced sound. The auditory characteristic value in the function A can be set in advance. For example, when the absolute value Df is smaller than a predetermined lower limit value, the auditory characteristic function A (f) is set to 0, and when the absolute value Df is larger than the predetermined upper limit value, the auditory characteristic function A (f) is set to a constant value. It can be a predetermined value. According to such setting of the auditory characteristic function A (f), the correction parameter can be corrected more appropriately according to the human auditory characteristic. The function B (f) is a function representing a difference obtained by subtracting the intensity of the reproduced sound from the intensity of the ambient sound as described above, but other predetermined characteristic comparison used for comparing the ambient sound and the reproduced sound. A function may be set.

  Then, the correction parameter setting unit 17 sets the correction parameter so that the gain is adjusted as follows in the adjacent frequency band adjacent to the identified target frequency band. FIG. 4 is a diagram for explaining the setting of the correction parameter. For example, with reference to the gain reduction width g of the target frequency band BWk including the frequency fA, the reference gain reduction width g is 90 in the adjacent frequency bands BWk-1 and BWk + 1 on both sides of the target frequency band BWk. Decrease gain by%. Further, for the adjacent frequency bands BWk-2 and BWk + 2 on both sides, the gain is reduced by 80% of the reference gain reduction width g, and these are repeated. That is, from the central target frequency band BWk that changes the gain to the maximum, to the adjacent frequency bands BWk-1, BWk-2,... On the low frequency side, and adjacent frequency bands BWk + 1, BWk + 1 on the high frequency side. Further, the correction parameter setting unit 17 sets the correction parameter so that the change in gain becomes gentle. Thereby, the sound quality of the reproduced sound before adjustment is maintained as much as possible.

  According to the reproduced sound adjusting apparatus 1, the target frequency band related to the characteristics of the ambient sound relative to the reproduced sound is specified based on the frequency characteristics of the reproduced sound and the frequency characteristics of the ambient sound, and the reproduced sound and the ambient sound can be easily distinguished. Thus, the gain of the audio signal is increased or decreased in the specified target frequency band. For this reason, it is possible to avoid the inconvenience that the ambient sound is masked by the reproduction sound having a large volume as in the conventional apparatus, and this makes it impossible to hear the ambient sound.

  For example, when an announcer is reading news on TV news, a person in front of the TV talks to a person watching this TV. Usually, in such a situation, the voice of the announcer and the voice of the person in front of the television overlap in similar frequency bands, and it may be difficult to distinguish either voice. According to this playback sound adjustment device 1, the sound quality of the announcer's voice is adjusted according to the voice of the person in front of the television so that the voice of the person in front of the television and the voice of the announcer are separated and can be distinguished. Is done.

(Second Embodiment)
Next, a second embodiment of the reproduction sound adjusting apparatus according to the present invention will be described. The present embodiment is different from the first embodiment in that the Fourier transform processing unit 13 is not provided. FIG. 5 is a diagram for explaining processing for specifying a frequency band related to the characteristics of ambient sounds. Configurations and operations related to processing other than the processing described here are the same as those in the first embodiment. The intensity of the ambient sound is maximum at the frequencies fA2 and fC2, and is minimum at the frequency fB2. The frequency band specifying unit 16 extracts these extreme values. The correction parameter setting unit 17 reduces the gain of the reproduced sound by a predetermined gain in a frequency band including the frequency fA2 where the intensity of the ambient sound is maximum and a frequency band including the frequency fC2 where the intensity is maximum. Further, the correction parameter is set so that the gain of the reproduced sound is increased by a predetermined gain in the frequency band including the frequency fB2 where the intensity of the ambient sound is minimized. In particular, the reproduction sound adjusting apparatus does not require the Fourier transform of the reproduction sound as in the Fourier transform processing unit 13 because the frequency characteristic of the reproduction sound is not used when setting the correction parameter.

  According to the reproduction sound adjusting device, the target frequency band related to the characteristics of the ambient sound is identified based on the frequency characteristics of the ambient sound, and the identified target frequency band is identified so that the reproduction sound and the ambient sound can be easily distinguished. The gain of the reproduced audio signal is increased or decreased. Although the present apparatus has a simpler configuration than the first embodiment described above, it is also possible to avoid the disadvantages caused by the conventional apparatus.

(Other embodiments, etc.)
As mentioned above, although this invention was demonstrated by specific embodiment, this invention is not limited to the said embodiment, It can change and implement in the range which does not deviate from the summary of this invention. In the above embodiment, it is assumed that the frequency range in which a person can feel sound is divided into n frequency bands, and the multiband equalizer 11 changes the gain in all these frequency bands. On the other hand, the gain may be changed only within a specific frequency band specified in advance. For example, when the reproduction sound adjusting device is mounted on an automobile, the gain can be changed only in a specific frequency band range corresponding to the characteristics of the ambulance siren sound (warning sound). According to this device, if an ambulance siren sounds while playing music, the sound quality of the music being played is adjusted according to the siren sound, so the driver can easily notice the siren sound. it can. In addition, a predetermined input unit and a setting unit may be provided, and the setting unit may set the specific frequency band range based on a user input received by the input unit.

  In the above embodiment, the reproduction sound adjusting device has the speaker 12 that outputs the reproduction sound whose gain is changed in a part of the frequency band, and outputs the reproduction sound from the headphones or the earphones. Also good. In this case, when the microphone 14 is provided on the back side of the headphone or the earphone (the side opposite to the side where the head is applied to the ear), the reproduced sound output from the headphone or the like is not mixed with the ambient sound picked up by the microphone 14. rare. In addition, the microphone 14 does not pick up the reproduced sound from the speaker 12, that is, the ambient sound does not include the reproduced sound as much as possible (for example, the distance from the television which is the viewing distance of the television is about 2 to 3 m). The directivity of the microphone 14 and the arrangement of the speaker 12 and the microphone 14 can be set. Even in these cases, it is effective to use a function representing a difference obtained by subtracting the intensity of the reproduced sound from the intensity of the ambient sound as the characteristic comparison function B (f) in the above equation (1). Furthermore, for example, terms added to the characteristic comparison function B (f) are based on the output characteristics of the speaker, the input characteristics of the microphone, the acoustic characteristics of the listening room, and the characteristics of the sound generated by the vibration of the reproduction sound adjusting device. May be set. More detailed correction parameters can be set by additional terms based on these characteristics.

  Further, the frequency characteristic comparison unit 16 increases or decreases the gain of the reproduced sound by the difference between the intensity of the ambient sound and the intensity of the reproduced sound in the first embodiment, and by the intensity of the ambient sound in the second embodiment. The frequency band to be used (the above-mentioned frequency band BW (k)) was specified. The ambient sound intensity and the playback sound intensity can be used by other methods, that is, an arbitrary function can be constructed from the ambient sound intensity and the playback sound intensity, and the frequency band can be specified based on the characteristics of this function. it can. The function for specifying the frequency band can be a function similar to the correction parameter or a different function.

  In the above embodiment, the correction parameter setting unit 17 gently reduces the gain change of the reproduced sound by a predetermined gain in the frequency band where the intensity of the ambient sound is maximum as shown in FIG. The correction parameters were set as follows. On the other hand, in order to simplify the control, the correction parameter setting unit 17 may set the correction parameter so that the gain of the reproduced sound becomes 0 in this frequency band.

It is a block diagram which shows the structure of the reproduction | regeneration sound adjustment apparatus as the 1st Embodiment of this invention. 6 is a diagram for explaining operations of a frequency band specifying unit 16 and a correction parameter setting unit 17. FIG. 6 is a diagram for explaining details of processing in a frequency band specifying unit 16; FIG. It is a figure for demonstrating the setting of the correction parameter with respect to the adjacent frequency band by the correction parameter setting part. It is a figure for demonstrating the detail of the process in the frequency band specific | specification part 16 in the reproduction | regeneration sound adjustment apparatus of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reproduction sound adjustment apparatus 11 ... Multiband equalizer 12 ... Speaker 13 ... Fourier-transform processing part (reproduction sound characteristic acquisition means)
14 ... Microphone (Ambient sound detection means)
15 ... Fourier transform processing unit (ambient sound characteristic acquisition means)
16: Frequency band specifying unit 17: Correction parameter setting unit

Claims (10)

In a reproduction sound adjustment device that adjusts a reproduction sound that is reproduced and output based on ambient sounds including sounds emitted in the surroundings,
Ambient sound detection means for detecting the ambient sound and generating an ambient sound signal;
Ambient sound characteristic acquisition means for acquiring frequency characteristics of the generated ambient sound signal;
A frequency band specifying means for specifying at least one frequency band of a plurality of predetermined frequency bands as a target frequency band related to the characteristics of the ambient sound, based on the frequency characteristics of the acquired ambient sound signal;
Audio adjusting means for changing a gain of an audio signal reproduced as the reproduced sound in the identified target frequency band;
A reproduction sound adjusting device comprising: The sound adjusting means is
Correction parameter setting means for setting a correction parameter for correcting the gain of the audio signal in the target frequency band specified by the frequency band specifying means;
The reproduction sound adjusting apparatus according to claim 1, further comprising: an equalizer that increases or decreases the gain in the specified target frequency band based on the set correction parameter. The frequency band specifying means includes
The reproduction sound adjusting apparatus according to claim 2, wherein a frequency band including a frequency at which the intensity of the ambient sound is maximum or minimum is specified as the target frequency band. The correction parameter setting means includes
The gain of the audio signal is reduced in a target frequency band including a frequency where the intensity of the ambient sound is maximum, and the gain of the audio signal is increased in a target frequency band including a frequency where the intensity of the ambient sound is minimum. The reproduction sound adjusting apparatus according to claim 3, wherein the correction parameter is set so as to be increased. The correction parameter setting means includes
The correction parameter in the target frequency band specified by the frequency band specifying unit is the intensity of the ambient sound in the target frequency band obtained based on the frequency characteristic of the ambient sound signal acquired by the ambient sound characteristic acquiring unit. The reproduction sound adjusting device according to claim 3 or 4, wherein the reproduction sound adjusting device is set using an auditory characteristic value in the target frequency band obtained based on a human auditory characteristic specified in advance. Reproduction sound characteristic acquisition means for acquiring the frequency characteristic of the audio signal,
The frequency band specifying means includes
Based on the frequency characteristic of the audio signal acquired by the reproduction sound characteristic acquisition unit and the frequency characteristic of the ambient sound signal acquired by the ambient sound characteristic acquisition unit as the target frequency band, the intensity of the ambient sound The reproduction sound adjusting device according to claim 2, wherein a frequency band including a frequency at which a difference between the intensity of the reproduction sound and the intensity of the reproduction sound by the audio signal is maximized or minimized is specified. The correction parameter setting means includes
Targets that reduce the gain of the audio signal in a target frequency band including a frequency at which the difference obtained by subtracting the intensity of the reproduced sound by the audio signal from the intensity of the ambient sound includes a frequency at which the difference is minimized The reproduction sound adjusting apparatus according to claim 6, wherein the correction parameter is set so that the gain is increased in a frequency band. The correction parameter setting means includes
The correction parameter in the target frequency band specified by the frequency band specifying means, the intensity of the ambient sound in the target frequency band obtained based on the frequency characteristics of the ambient sound signal acquired by the ambient sound characteristic acquisition means, And a characteristic comparison value obtained by comparing the intensity of the reproduced sound by the audio signal in the target frequency band obtained based on the frequency characteristic of the audio signal acquired by the reproduced sound characteristic acquiring means, and designated in advance The reproduction sound adjusting device according to claim 6 or 7, wherein the reproduction sound adjusting device is set using an auditory characteristic value in the target frequency band obtained based on a human auditory characteristic. In a reproduction sound adjustment method for adjusting a reproduction sound to be reproduced and output based on ambient sounds including sounds emitted in the surroundings,
A detection step of detecting the ambient sound and generating an ambient sound signal;
A first acquisition step of acquiring a frequency characteristic of the generated ambient sound signal;
A specifying step of specifying at least one frequency band of a plurality of predetermined frequency bands as a target frequency band related to the characteristics of the ambient sound based on the frequency characteristics of the acquired ambient sound signal;
A changing step of changing a gain of an audio signal reproduced as the reproduced sound in the specified target frequency band;
A playback sound adjustment method comprising: A second acquisition step of acquiring a frequency characteristic of the audio signal;
In the specifying step, based on the frequency characteristics of the audio signal acquired in the second acquisition step and the frequency characteristics of the ambient sound signal acquired in the first acquisition step, the ambient sound intensity and the The reproduction sound adjustment method according to claim 9, wherein a frequency band including a frequency at which a difference from the intensity of the reproduction sound by the audio signal is maximized or minimized is specified as the target frequency band.

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