JP2012095254A - Volume adjustment device, volume adjustment method, volume adjustment program and acoustic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a volume adjustment technique capable of appropriate volume adjustment.SOLUTION: A volume adjustment device includes: means for imparting, to sound signals, characteristic correction corresponding to characteristic change received after the sound signals are inputted to a sound output part until they are outputted as echo components from a sound collection part which collects surrounding sound; means for dividing the characteristic-corrected sound signals into a plurality of frequency bands; means for respectively detecting the strengths of the respective divided signals; means for dividing sound collection signals outputted from the sound collection part into the same respective frequency bands as the band division; means for respectively detecting the strengths of the respective divided signals for which the sound collection signals are divided; means for comparing the strengths of the respective divided signals of the characteristic-corrected sound signals with the strengths of the respective divided signals of the sound collection signals for each of the same frequency band; and volume change means for changing the volume of the sound signals on the basis of the comparison result.

Description

  The present invention relates to a technique for adjusting sound volume.

  In the following Patent Documents 1 to 4, devices for adjusting the output volume of a speaker in consideration of ambient noise are proposed. For example, Patent Literature 3 below discloses a signal level (noise level) of the above-described predetermined frequency band of a collected sound signal that is emitted from a speaker and collected (collected) from a broadcast area, with an audio signal from which only the predetermined frequency band has been removed. Has been proposed, and the volume of the speaker is automatically adjusted according to the noise level.

  Such an automatic volume control technique can obtain a particularly high effect when applied to an audio output device placed in an environment where manual operation is difficult. For example, currently there are music playback devices and video output devices that can be brought into the bathroom, but it is effective if the automatic volume control technology is applied to such audio output devices. This is because there are many scenes where volume adjustment is desired because there are loud noise sources such as shower sounds in the bathroom, but on the other hand, manual operation is often difficult.

JP 2008-228184 A Japanese Patent Laid-Open No. 06-310962 Japanese Patent Laid-Open No. 06-334457 Japanese Patent Laid-Open No. 10-056346

  In the automatic volume control technique as described above, it is important to detect a noise component with high sensitivity from a collected signal picked up by a macrophone. Since the sound collection signal includes an echo component of the sound output from the sound output device, it is desired that the automatic sound volume adjustment technique accurately detect only the noise component in consideration of the echo component.

  An object of the present invention is to provide a volume adjustment technique that enables appropriate volume adjustment.

  Each aspect of the present invention employs the following configurations in order to solve the above-described problems.

  A 1st aspect is related with the volume control apparatus which adjusts the volume of the audio | voice output from an audio | voice output part. The volume control device according to the first aspect is subject to a characteristic change that is received from when a sound signal is input to the sound output unit to when the sound signal is output as an echo component from the sound collecting unit that collects ambient sound. Characteristic correction means for applying a corresponding characteristic correction to the audio signal, output-side band dividing means for dividing the audio signal whose characteristic is corrected by the characteristic correction means into a plurality of frequency bands, and division by the output-side band dividing means Output side intensity detecting means for detecting the intensity of each divided signal, input side band dividing means for dividing the collected sound signal output from the sound collecting section into the same frequency bands as the output side band dividing means, and The input side intensity detecting means for detecting the intensity of each divided signal divided by the input side band dividing means, and the intensity of each divided signal detected by the output side intensity detecting means and the input side intensity detecting means Ri comprises a comparing intensity comparing means and intensity of the detected respective divided signals for each same frequency band, based on a comparison result by the intensity comparing means, and volume changing means for changing the volume of the audio signal.

  A 2nd aspect is an audio equipment provided with the said volume control apparatus, the said sound collection part, and the said audio | voice output part.

  A 3rd aspect is related with the volume adjustment method of adjusting the volume of the audio | voice output from an audio | voice output part. The volume adjustment method according to the third aspect is characterized in that a change in characteristics received from when a sound signal is input to the sound output unit to when the sound signal is output as an echo component from a sound collecting unit that collects ambient sound. Is applied to the sound signal, the sound signal whose characteristics are corrected is divided into a plurality of frequency bands, and the intensity of each of the divided signals is detected and output from the sound collecting unit. The collected sound signal is divided into the same frequency bands as the band division, the intensity of each divided signal obtained by dividing the collected sound signal is detected, and the intensity of each divided signal of the sound signal whose characteristics are corrected and the collected signal are detected. This includes comparing the intensity of each divided signal of the sound signal for each same frequency band, and changing the volume of the sound signal based on the comparison result.

  Note that another aspect of the present disclosure may be a volume control program that causes a computer to realize the above-described configurations or processes, or a computer-readable storage medium that records such a volume control program. Also good.

  According to each aspect described above, it is possible to provide a volume adjustment technique that enables appropriate volume adjustment.

It is a conceptual diagram which shows the structural example of the audio equipment to which the volume control apparatus in this embodiment was applied. It is a conceptual diagram which shows the structural example of a volume control apparatus. It is a figure which shows the example of the characteristic of a band division filter. It is a figure which shows the structural example of an output side zone | band division | segmentation part.

  Hereinafter, a volume control device according to an embodiment of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate. Further, the following embodiments are exemplifications, and the present invention is not limited to the configurations of the following embodiments.

[Embodiment]
FIG. 1 is a conceptual diagram illustrating a configuration example of an audio device to which the volume adjusting device according to the present embodiment is applied. The volume adjusting device 10 in the present embodiment adjusts the volume of the sound output from the acoustic device 1 as in the example of FIG. The volume adjusting device 10 constitutes the acoustic device 1 together with the microphone 3, the speaker 5, and the like. Here, the acoustic device 1 is configured to output sound from a mobile phone, a portable music device, a sound reproducing device such as a compact disc (CD) player, a broadcast receiving device such as a television or a radio, a musical instrument such as a piano. Means the device to output.

  The microphone 3 picks up surrounding sound and converts this sound into an electric signal. The microphone 3 is generally called a sound collection unit. Hereinafter, a signal collected and converted by the microphone 3 is referred to as a collected signal. The microphone 3 sends the collected sound signal to the volume adjusting device 10. Although this embodiment does not limit the performance and specific configuration of the microphone 3 such as directivity, sensitivity, and frequency band, the microphone 3 is preferably a microphone 3 that covers a wide frequency band with high sensitivity.

  The speaker 5 converts an electrical signal into sound and outputs the converted sound. The speaker 5 is generally called an audio output unit. Hereinafter, an electrical signal sent to the speaker 5 is referred to as an output audio signal. The present embodiment does not limit the performance and specific configuration of the speaker 5.

  The volume adjusting device 10 receives an audio signal (hereinafter referred to as an input audio signal) from a processing unit that generates audio to be output from the acoustic device 1, such as a decoder or a broadcast receiver. Adjust the volume. The volume control device 10 adjusts the volume according to the noise component included in the collected sound signal obtained from the microphone 3. The volume adjusting device 10 sends the volume-adjusted audio signal to the speaker 5 as an output audio signal.

  The volume adjusting device 10 includes a characteristic correction unit 11 that applies characteristic correction corresponding to a characteristic change received between the output audio signal reaching the speaker 5 and being output as an echo component from the microphone 3 to the input audio signal. , An output side band dividing unit 12 that divides the sound signal whose characteristics are corrected by the characteristic correcting unit 11 into a plurality of frequency bands, and each output side that detects the intensity of each divided signal divided by the output side band dividing unit 12 The intensity detection unit 13, the input side band division unit 22 that divides the collected sound signal output from the microphone 3 into the same frequency bands as the output side band division unit 12, and each division divided by the input side band division unit 22 Each input side intensity detector 23 for detecting the intensity of each signal, and each divided signal intensity detected by the output side intensity detector 13 and detected by the input side intensity detector 23 Includes a strength comparison unit 14 and the intensity of each split signal is compared every the same frequency band that is based on the comparison result by the strength comparator 14, and the volume changing unit for changing the volume of the input speech signal.

  According to this aspect, the audio signal whose characteristic is corrected by the characteristic correcting unit 11 becomes a signal that is the same as or approximates to the echo component that is transmitted from the speaker 5 and collected by the microphone 3. The audio signal whose characteristic is corrected by the characteristic correcting unit 11 can be called a pseudo echo signal. Thereby, when there is no sound other than the sound output from the speaker 5 around the microphone 3 (no noise), the sound collection signal output from the microphone 3 and the sound whose characteristics are corrected by the characteristic correcting unit 11 It is the same or approximate to the signal. Here, approximating means that the intensity of each audio signal in each frequency band falls within a predetermined range, and this predetermined range is appropriately set according to the characteristics of the microphone 3, the speaker 5, and the volume control device 10. Information to get.

  In the above aspect, the pseudo echo signal generated by the characteristic correction unit 11 and the sound collection signal obtained from the microphone 3 as described above are placed in the same frequency band by the output side band division unit 12 and the input side band division unit 22. The intensity of the divided signals in each frequency band is detected by each output-side intensity detector 13 and each input-side intensity detector 23. Then, the intensity comparison unit 14 compares the intensity of each divided signal for each frequency band.

  As a result, when there is no noise around the microphone 3, the intensity of each divided signal is the same or approximate. On the other hand, when there is noise in the surroundings, the intensity of the divided signal of the collected sound signal is larger than the intensity of the pseudo echo signal in at least one frequency band. Here, if there is a frequency band in which the echo component is larger than the noise component in the collected sound signal, there is a possibility that the noise cannot be correctly recognized because the noise component is buried in the echo component. However, according to the above aspect, even in such a case, ambient noise can be detected with high sensitivity by comparing the intensity in each of a plurality of frequency bands.

  In the above aspect, the volume of the audio signal is changed based on the result of the intensity comparison in each frequency band as described above. Therefore, according to the above aspect, it is possible to detect ambient noise with high sensitivity and appropriately adjust the volume according to the detected noise level. Moreover, according to the said aspect, the above effects are acquired by simple structure which equips the input side and the output side with the same zone | band division | segmentation part (12 and 22) and the same intensity | strength detection part (13 and 23), respectively. be able to.

〔Device configuration〕
Hereinafter, the configuration of the above-described volume adjusting device 10 will be described in more detail.
FIG. 2 is a conceptual diagram illustrating a configuration example of the volume adjusting device 10. As shown in FIG. 2, the volume adjusting device 10 includes a characteristic correcting unit 11, an output side band dividing unit 12, a plurality of output side intensity detecting units 13, an intensity comparing unit 14, a gain calculating unit 15, a gain shaping unit 16, It includes an amplifying unit 18, a shared memory 20, an input side band dividing unit 22, a plurality of input side intensity detecting units 23, and the like. The gain calculation unit 15, the gain shaping unit 16, and the volume amplification unit 18 can also be generally called a volume change unit.

  Each of these processing units includes a processing unit that handles a collected sound signal obtained from the microphone 3 (hereinafter may be referred to as an input side processing unit), and a processing unit that handles an output audio signal sent to the speaker 5 (hereinafter, output). And a side processing unit). The input side processing unit includes an input side band dividing unit 22 and an input side intensity detecting unit 23, and the output side processing unit includes a characteristic correcting unit 11, an output side band dividing unit 12, an output side intensity detecting unit 13, An intensity comparison unit 14, a gain calculation unit 15, a gain shaping unit 16, and a volume amplification unit 18 are included. The shared memory 20 is used by both the input side intensity detection unit 23 that is an input side processing unit and the intensity comparison unit 14 that is an output side processing unit.

  Each of these processing units may be realized individually or in combination and realized as a hardware component, a software component, or a combination of a hardware component and a software component. May be. A hardware component is a hardware circuit such as a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a gate array, a combination of logic gates, a signal processing circuit, an analog circuit, etc. is there. A software component is realized by executing data (program) on one or more memories by one or more processors (for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), etc.). Software parts (fragments) such as tasks, processes and functions.

  The characteristic correcting unit 11 imparts to the input audio signal characteristic correction corresponding to a characteristic change received from when the input audio signal reaches the speaker 5 until it is output as an echo component from the microphone 3. Giving this characteristic correction to the input audio signal means performing signal processing that imitates the characteristic change. In a specific example, the signal processing includes a filter that imitates the characteristics of the speaker 5 and the microphone 3, a volume process corresponding to attenuation, a delay process that imitates a delay caused by the distance between the speaker 5 and the microphone 3, and the like. . The signal processing may include volume change processing equivalent to the volume change finally applied by the volume amplification unit 18.

  The characteristic change may be set in advance in consideration of the environment in which the acoustic device 1 is used, or by analyzing the test sound and the echo component by outputting the test sound in the absence of noise. , May be set automatically.

  The output side band dividing unit 12 is realized as a set of a plurality of band dividing filters. 2 shows an example in which the output side band dividing unit 12 divides the input audio signal into three frequency bands. The same number of output side intensity detection units 13 as the number of divisions of the output side band division unit 12 are provided.

  In the present embodiment, the number of divisions, the division frequency band, and the like are not limited. However, since the scales of the output-side band dividing unit 12 and the output-side intensity detecting unit 13 are determined according to the number of divisions, the number of divisions is related to the device scale and cost. The number of divisions and the division frequency band are also related to the noise component detection accuracy. This is because, as described above, there may be a frequency band that is not detected because the noise component is buried in the echo component. Therefore, it is desirable that the number of divisions, the division frequency band, and the like be appropriately determined in consideration of such a viewpoint.

  3A and 3B are diagrams illustrating an implementation example of the output-side band dividing unit 12. FIG. 3A is a diagram illustrating an example of the characteristics of the band division filter, and FIG. 3B is a diagram illustrating a configuration example of the output side band division unit 12. As shown in FIG. 3A, the band division filter includes a low-pass filter (hereinafter referred to as LPF) and a high-pass filter (hereinafter referred to as HPF). The LPF suppresses frequency components higher than the division frequency and passes frequency band components lower than the division frequency. The HPF suppresses frequency components lower than the division frequency and passes frequency band components higher than the division frequency.

  In the example of FIG. 3B, a configuration example in which the output side band dividing unit 12 divides the input audio signal into four frequency bands is shown. In this example, the output side band dividing unit 12 includes band dividing filters 40, 43 and 46. The band division filter 40 divides the input signal into a subband signal having a frequency component lower than the division frequency 1-2 (first band output) and a subband signal having a frequency component higher than the division frequency 1-2. The band division filter 43 converts a subband signal having a frequency component higher than the division frequency 1-2 into a subband signal (second band output) having a frequency component lower than the division frequency 2-3 and a frequency component higher than the division frequency 2-3. Into subband signals. The band division filter 46 converts a subband signal having a frequency component higher than the division frequency 2-3 into a subband signal (third band output) having a frequency component lower than the division frequency 3-4 and a frequency component higher than the division frequency 3-4. And subband signals (fourth band output). According to the example of FIG. 3B, the output side band dividing unit 12 divides the input signal into four frequency bands.

  Further, it is desirable that the frequency band to be divided is divided in a band where the characteristics of the frequency characteristics of the speaker 5 appear. For example, if the speaker 5 cannot output a frequency equal to or lower than f0, f0 is set as the division frequency.

  In the example of FIG. 2, there are three output side intensity detectors 13 (13 (# 1), 13 (# 2), and 13 (# 3)) according to the number of divisions of the output side band divider 12. . Since the output side intensity detectors 13 (# 1), 13 (# 2), and 13 (# 3) are the same, they are collectively referred to as the output side intensity detector 13 unless particularly distinguished. The The output-side intensity detector 13 receives any one of the divided signals from the output-side band divider 12 and measures the intensity (level value) at regular intervals (for example, 20 milliseconds (ms)) of this divided signal. . For measuring the intensity, there are methods using a peak value, an effective value (RMS), and the like. The intensity of each divided signal detected by the output side intensity detector 13 is sent to the intensity comparator 14.

  The input side band dividing unit 22 is the same as the above output side band dividing unit 12 except for the signal to be processed. The input side band dividing unit 22 divides the collected sound signal by the same number of divisions as the output side band dividing unit 12 and the frequency band to be divided.

  The input side intensity detector 23 is the same as the output side intensity detector 13 except for the signal to be processed. The input side intensity detecting unit 23 stores the detected intensity (level value) of each divided signal in the shared memory 20.

  The shared memory 20 stores the intensity of each divided signal sent from each input-side intensity detector 23 in a predetermined area. The intensity of each divided signal may be overwritten each time it is measured by each input-side intensity detector 23, or may be accumulated for a predetermined time. The strength stored in the shared memory 20 is read by the strength comparison unit 14. Note that the timing of writing and reading may not be synchronized, and may be performed at arbitrary timings.

  The intensity comparison unit 14 reads the intensity of each divided signal on the input side from the shared memory 20, the intensity of each read divided signal, the intensity of each divided signal sent from each output side intensity detecting unit 13, Are compared for each frequency band, and the difference is calculated.

  Here, the frequency bands of the signals handled by the output side intensity detector 13 (# 1) and the input side intensity detector 23 (# 1) are the same, and the output side intensity detector 13 (# 2) and the input side The frequency band of the signal handled by the intensity detector 23 (# 2) is the same, and the frequency band of the signal handled by the output side intensity detector 13 (# 3) and the input side intensity detector 23 (# 3) Are the same. In this case, the intensity comparison unit 14 calculates a value obtained by subtracting the signal intensity sent from the output side intensity detection unit 13 (# 1) from the signal intensity detected by the input side intensity detection unit 23 (# 1). A value obtained by subtracting the signal intensity sent from the output side intensity detector 13 (# 2) from the signal intensity detected by the side intensity detector 23 (# 2) is calculated, and the input intensity detector 23 (# 3) A value obtained by subtracting the signal intensity sent from the output-side intensity detector 13 (# 3) is calculated.

  The intensity comparison unit 14 subtracts 0 or more of the calculated subtraction values, that is, the signal intensity detected by the input side intensity detection unit 23 is greater than the signal intensity detected by the output side intensity detection unit 13. The subtraction values calculated for a large frequency band are integrated, and the integrated value is output as a comparison result. Here, each frequency band is denoted by i, the divided signal of the frequency band i stored in the shared memory 20 is denoted by Pt [i], and the divided signal of the frequency band i output from the output side intensity detector 13 is Pr. When represented by [i], the processing of the intensity comparison unit 14 is represented by the following equation.

D = Σramp (Pt [i] −Pr [i])
“ramp (x)” represents a ramp function, and is a function in which “ramp (x)” = x when x is 0 or more, and “ramp (x) = 0” when x is less than 0. That is, if at least one of the divided signals has the intensity of the divided signal on the input side larger than the intensity of the divided signal on the output side, the intensity comparing unit 14 outputs a positive value (D).

  The gain calculator 15 calculates a gain value according to the comparison result (difference integrated value: D) output from the intensity comparator 14. For example, the gain calculation unit 15 calculates the gain value by multiplying the difference integrated value by a predetermined proportional coefficient. The predetermined proportionality coefficient may be set in advance according to the characteristics of the sound volume amplifying unit 18, noise generated in the environment in which the audio device 1 is used, or may be set in a manually adjustable state. May be. For example, the predetermined proportionality coefficient is set based on a value manually adjusted by the user so that the sound volume is appropriate in a state where a certain noise is generated (for example, in a showering state). May be.

  The gain shaping unit 16 shapes the gain value obtained by the gain calculating unit 15 so that the volume changes naturally. Since the signal strength stored in the shared memory 20 and the signal strength detected by the output-side strength detector 13 are values measured at predetermined intervals, they vary with time. As a result, the gain value calculated based on such signal intensity also varies with time. The gain shaping unit 16 shapes the waveform so that such time variation of the gain value becomes a natural volume change for the user.

  Waveform shaping by the gain shaping unit 16 is realized by using at least one of the following methods, for example. First, there is a technique in which the output is not changed until the gain value calculated by the gain calculation unit 15 exceeds a predetermined threshold value. Second, there is a technique for keeping the output change rate constant. Third, there is a technique in which the output is not changed for a predetermined time after the output is changed.

  The volume amplifying unit 18 amplifies the volume of the input audio signal according to the waveform shaped gain sent from the gain shaping unit 16.

[Action and effect]
In the specific embodiment described above, the value obtained by subtracting the intensity of the divided signal of the input audio signal from the intensity of the divided signal of the collected sound signal in the intensity comparing unit 14 is equal to or greater than 0 for each frequency band. Is accumulated for the target. The gain calculation unit 15 calculates a gain value based on the integrated value, the gain shaping unit 16 shapes the gain value, and the volume amplification unit 18 adjusts the volume of the input audio signal according to the shaped gain. Adjusted.

  In such a manner, even if there is a frequency band in which the noise component is buried in the echo component, the noise component can be detected in another frequency band. Therefore, according to this aspect, a noise component can be detected with high sensitivity.

  In this aspect, the signal intensity of only the noise component (the integrated value of the values obtained by subtracting the intensity of the divided signal of the input voice signal from the intensity of the divided signal of the collected sound signal) is accurately detected, and amplified based on this value. A rate (gain) is determined. Therefore, according to this aspect, it is possible to perform appropriate automatic volume adjustment according to the level of ambient noise.

  Furthermore, in this aspect, the comparison result of the signal intensity including the time variation is waveform-shaped by the gain shaping unit 16, so that sudden and intense volume change can be prevented and the volume change natural to the user can be achieved. Moreover, since only the volume of the input audio signal is changed and output as an output audio signal, the characteristics of the output audio can be improved.

[Modification]
In the configuration example shown in FIGS. 1 and 2 described above, the volume adjusting device 10 and the microphone 3 are shown separately, but the volume adjusting device 10 may include the microphone 3.

  Further, although the effect of natural volume change cannot be obtained, the gain shaping unit 16 may be omitted in the configuration example shown in FIG. 2 and a gain value that is not waveform-shaped may be sent to the volume amplification unit 18. In the example of FIG. 2, the shared memory 20 is clearly shown. However, the shared memory 20 may be eliminated, and the intensity of each divided signal may be sent directly from the input side intensity detection unit 23 to the intensity comparison unit 14.

In addition, the intensity comparison unit 14 may output an integrated value obtained by multiplying the difference value of each frequency band by a weight (W [i]) corresponding to each frequency band as a comparison result.
D = Σ (W [i] × ramp (Pt [i] −Pr [i]))
Further, the intensity comparison unit 14 outputs the number of frequency bands in which the intensity of the divided signal of the collected sound signal is greater than the intensity of the divided signal of the input audio signal as a comparison result, although the accuracy of the gain value is reduced. May be. In this case, the processing of the intensity comparison unit 14 is expressed by the following equation.
D = Σ (W [i] × step (Pt [i] −Pr [i]))
step (x) represents a step function, which is step (x) = 1 when x is 0 or more, and step (x) = 0 when x is less than 0.

DESCRIPTION OF SYMBOLS 1 Audio equipment 3 Microphone 5 Speaker 10 Volume control apparatus 11 Characteristic correction part 12 Output side band division part 13 Output side intensity | strength detection part 14 Intensity comparison part 15 Gain calculation part 16 Gain shaping part 18 Volume amplification part 20 Shared memory 22 Input side band Dividing unit 23 Input side intensity detecting unit 40, 43, 46 Band division filter

Claims (7)

In a volume adjustment device that adjusts the volume of sound output from the audio output unit,
Gives the sound signal a characteristic correction corresponding to a characteristic change received from when the sound signal is input to the sound output unit until the sound signal is output as an echo component from the sound collecting unit that collects the surrounding sound. Characteristic correction means for
Output-side band dividing means for dividing the audio signal whose characteristics are corrected by the characteristic correcting means into a plurality of frequency bands;
Output-side intensity detecting means for detecting the intensity of each divided signal divided by the output-side band dividing means;
Input-side band dividing means for dividing the collected sound signal output from the sound collecting section into the same frequency bands as the output-side band dividing means;
Input side intensity detecting means for detecting the intensity of each divided signal divided by the input side band dividing means;
An intensity comparing means for comparing the intensity of each divided signal detected by the output side intensity detecting means and the intensity of each divided signal detected by the input side intensity detecting means for each same frequency band;
Volume change means for changing the volume of the audio signal based on the comparison result by the intensity comparison means;
A volume control device comprising:   The intensity comparing means relates to a frequency band in which the signal intensity detected by the input side intensity detecting means is greater than the signal intensity detected by the output side intensity detecting means among the plurality of frequency bands. 2. The volume adjusting apparatus according to claim 1, wherein an integrated value of a value obtained by subtracting the signal intensity detected by the output side intensity detecting means from the signal intensity detected by the detecting means is output as a comparison result. The volume changing means is
Gain calculating means for calculating a gain value according to the comparison result by the intensity comparing means;
Gain shaping means for shaping the waveform of the gain value at predetermined intervals calculated by the gain calculating means;
Volume amplification means for amplifying the volume of the audio signal in accordance with the gain shaped by the gain shaping means;
The volume control device according to claim 1, wherein the volume control device includes:   The gain shaping means includes a technique that does not change the output until the gain value calculated by the gain calculation means exceeds a predetermined threshold, a technique that keeps the output change rate constant, and a predetermined time after the output is changed. 4. The volume adjusting apparatus according to claim 3, wherein waveform shaping of the gain value is performed using at least one of methods that do not change the output. A volume control device according to any one of claims 1 to 4,
The sound collection unit;
The audio output unit;
An acoustic device comprising: In the volume adjustment method for adjusting the volume of the audio output from the audio output unit,
Gives the sound signal a characteristic correction corresponding to a characteristic change received from when the sound signal is input to the sound output unit until the sound signal is output as an echo component from the sound collecting unit that collects the surrounding sound. And
Dividing the characteristic-corrected audio signal into a plurality of frequency bands;
Detecting the intensity of each of the divided divided signals,
Dividing the sound collection signal output from the sound collection unit into the same frequency band as the band division,
Detecting the intensity of each divided signal obtained by dividing the collected sound signal;
Comparing the intensity of each divided signal of the characteristic-corrected audio signal and the intensity of each divided signal of the collected sound signal for each same frequency band,
Changing the volume of the audio signal based on the comparison result;
Volume adjustment method including that. In a volume adjustment program executed by a computer that adjusts the volume of audio output from the audio output unit,
The computer,
Gives the sound signal a characteristic correction corresponding to a characteristic change received from when the sound signal is input to the sound output unit until the sound signal is output as an echo component from the sound collecting unit that collects the surrounding sound. Characteristic correction means for
Output-side band dividing means for dividing the audio signal whose characteristics are corrected by the characteristic correcting means into a plurality of frequency bands;
Output-side intensity detecting means for detecting the intensity of each divided signal divided by the output-side band dividing means;
Input-side band dividing means for dividing the collected sound signal output from the sound collecting section into the same frequency bands as the output-side band dividing means;
Input side intensity detecting means for detecting the intensity of each divided signal divided by the input side band dividing means;
An intensity comparing means for comparing the intensity of each divided signal detected by the output side intensity detecting means and the intensity of each divided signal detected by the input side intensity detecting means for each same frequency band;
Volume change means for changing the volume of the audio signal based on the comparison result by the intensity comparison means;
Volume control program characterized by functioning.

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