JP3351742B2 - Adaptive sound quality volume control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound source signal to be loudspeaked in a sound field such as a vehicle interior, a listening room, and a public space. The present invention relates to an adaptive sound quality volume control device used for controlling a frequency characteristic and a volume of a sound.

[0002]

2. Description of the Related Art Conventionally, as this type of acoustic device, there are those disclosed in Japanese Patent Application Laid-Open Nos. 55-30240, 6-334457, and 9-14867. FIG. 3 shows an example of the configuration of a conventional audio device that reproduces sound while compensating for masking due to noise.

In FIG. 3, reference numeral 301 denotes a sound source such as a CD player, cassette tape, radio, or announcement;
302 is a microphone, 303 is microphone signal analysis means,
Reference numeral 311 denotes a sound source signal analyzing unit for calculating the level of each frequency band of the sound source signal, 304 denotes a noise signal calculating unit, 3
05 is a compensation amount calculating means, 306 is an adjustment amount updating means, 30
Reference numeral 7 denotes frequency characteristic adjusting means such as an equalizer, 308 denotes volume adjusting means such as a volume, 309 denotes an amplifier, 310 denotes a speaker, and 311 denotes sound source signal analyzing means. Reference numeral 312 denotes a control amount calculating means, and the microphone signal analyzing means 30
3, noise signal calculating means 304, compensation amount calculating means 305,
It comprises an adjustment amount updating unit 306 and a sound source signal analyzing unit 311.

Next, the operation of the above conventional example will be described. In FIG. 3, frequency characteristics of a sound source signal such as an announcement or a sound source output from a sound source 301 such as a CD are adjusted by changing gains of a plurality of frequency bands by a frequency characteristic adjusting unit 307 such as an equalizer, and a volume or the like is adjusted. The volume is adjusted by the volume adjusting means 308, amplified by the amplifier 309, and emitted to the space by the speaker 310. The output signal of the sound source 301 is also input to a sound source signal analysis unit 311, and the sound source signal level for each of one or more frequency bands is analyzed at regular time intervals, and the noise signal calculation unit 304 and the compensation amount calculation unit 311 are analyzed.
05 is one input.

[0005] In the space where the speaker 310 is installed, when the microphone 302 detects noise near the place where the sound output from the speaker 310 is received or at a high correlation with the ambient noise at the listening place, the signal becomes: The microphone signal level of one or more frequency bands is analyzed by the microphone signal analysis unit 303 at regular time intervals, and is input to the other input of the noise signal calculation unit 304. Since the microphone 302 often includes a sound source signal that is being reproduced or loudspeaked together with the ambient noise, the noise signal calculating unit 304 calculates the level of the microphone signal calculated by the microphone signal analyzing unit 303 for each frequency band. By subtracting the sound source signal level calculated by the sound source signal analyzing means 311, only the noise signal component level is calculated. When the noise signal level is calculated by subtracting the sound source signal level, the noise signal level is calculated in consideration of the current control state, that is, the adjustment amounts of the frequency characteristic adjustment unit 307 and the volume adjustment unit 308. The compensation amount calculation means 305 calculates the compensation amount at regular time intervals from, for example, the masking amount of the sound source signal by the noise signal, the energy ratio between the noise signal and the sound source signal, and the like.

[0006] The compensation amount analyzed at fixed time intervals by the sound source signal analyzing means 311 and the microphone signal analyzing means 303 is as follows.
If the compensation amount is directly used as the adjustment amount of the frequency characteristic adjustment unit 307 or the volume adjustment unit 308 because the amount of compensation greatly fluctuates with time, the sense of hearing becomes unnatural before and after updating the adjustment amount. Therefore, the compensation amount update unit 306 smoothly updates the adjustment amounts of the frequency characteristic adjustment unit 307 and the volume adjustment unit 308 by integrating the output signal of the compensation amount calculation unit 305, using an average or LPF, or by another method. The frequency characteristic adjusting means 307 and the volume adjusting means 3
08 changes the sound quality and volume of the sound source signal.

As described above, even in the conventional adaptive sound quality volume control device, the frequency characteristic and the sound volume of the sound source signal are changed according to the characteristics of the detected sound source signal and the characteristics of the ambient noise. Even if the characteristics of the ambient noise change, the reproduction can be performed so that the user can hear the same loudness as when there is no ambient noise.

[0008]

However, in the above-mentioned conventional adaptive sound quality volume control device, there is a difference between a sound part and a non-sound part in an announcement or the like, and a difference in intensity between rhythms in a music signal or the like. Since the frequency characteristic analysis result greatly changes in a short time, the calculation result of the compensation amount greatly changes in a short time due to a change in the sound source signal. If the frequency characteristics of the sound source signal are controlled using the compensation amount calculated in such a manner, the sound source signal responds more sensitively to the fluctuation of the sound source signal than to the change of the noise signal. Had the problem of accumulating.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problem. Even if there is ambient noise or the characteristics of the ambient noise change, the sound can be heard at the same loudness as when there is no ambient noise. It is an object of the present invention to provide an excellent adaptive sound quality volume control device capable of reproducing a sound source signal naturally without swaying, without being sensitive to fluctuations of the sound source signal, and without being sensitive to fluctuations of the sound source signal.

[0010]

In order to solve the above-mentioned problems, the present invention comprises a sound source signal analyzing means, a noise signal calculating means, a maximum value detecting means and a maximum value holding means, wherein a sound source signal is converted to a first value.
Of the output of frequency analysis in time intervals, it detects the maximum value in the second time interval longer than analysis time interval, the maximum value and the previous
The compensation amount is calculated using the noise signal level detected by the noise signal calculation means . As described above, even if the ambient noise is present or the characteristics of the ambient noise change, the sound is reproduced so that it can be heard at the same loudness as when there is no ambient noise, and it is sensitive to the fluctuation of the sound source signal. Thus, an excellent adaptive sound quality volume control device that reproduces a sound source signal naturally in a sense of hearing without fluctuation can be obtained.

[0011]

The invention according to claim 1 of the embodiment of the present invention includes a source signal analyzing means for outputting analyzing the signal level for each frequency band of the sound source signal at every first time interval, or a microphone
Signal level for each frequency band of ambient noise
A microphone signal analyzer that analyzes and outputs at every first time interval
And the sound source signal from the output of the microphone signal analysis means.
Noise that detects the noise signal level by subtracting the output of the analysis means
A sound signal calculation means, said in the sound source signal analyzing means
A maximum value detecting means for detecting a maximum value of the output of the sound source signal analyzing means second time interval longer than the first time interval for each of the frequency band, the maximum value detected by said maximum value detecting means and the maximum value holding means for holding the maximum value holding means
The maximum value held in the step and the value detected by the noise signal calculating means.
The an adaptive tone volume control device including a control amount calculating means and a compensation amount calculating means for calculating a compensation amount for compensating the circumferential囲騒sound by employing the noise signal level, if there is ambient noise Also, even if the characteristics of the ambient noise change, the sound is reproduced so that it can be heard with the same loudness as when there is no ambient noise. A sound source signal can be reproduced.

According to a second aspect of the present invention, there is provided a sound source signal analyzing means for analyzing and outputting a signal level for each frequency band of a sound source signal at a first time interval, and inputting from a microphone.
The signal level for each frequency band of the ambient noise
Microphone signal analysis means for analyzing and outputting at every interval,
From the output of the microphone signal analysis means,
Noise signal calculation to detect noise signal level by subtracting output
Means and said with the maximum value of the output of the sound source signal analyzing means second time interval longer than the first time interval in the source signal analysis means for detecting for each of the frequency band, the maximum value detection time interval But the maximum value detecting means for detecting a maximum value above a certain level, holds the maximum value detected <br/> by said maximum value detecting means, depending on the maximum value detection time interval from said maximum value detecting means If the maximum value output without the maximum value is larger than the currently held maximum value, the maximum value updating means for updating to the maximum value, and the maximum value holding the maximum value output from the maximum value updating means Holding means;
The maximum value held by the maximum value holding means and the noise signal
By using the detected noise signal level calculating means is an adaptive tone volume control device including a control amount calculating means and a compensation amount calculating means for calculating a compensation amount for compensating the circumferential囲騒sound, ambient noise Even if the sound is present or the characteristics of the ambient noise change, the sound is reproduced so that it can be heard at the same volume as when there is no ambient noise. The sound source signal can be reproduced naturally in terms of audibility.

According to a third aspect of the present invention, there is provided an adaptive sound quality volume control apparatus in which the control amount calculating means in the adaptive sound quality volume control apparatus according to the first or second aspect is realized by software. Can be

According to a fourth aspect of the present invention, there is provided a DSP (Digital) which uses at least a part of the control amount calculating means in the adaptive sound quality volume control device according to the first or second aspect.
Signal Proccessor), and a high-performance DSP can be realized.

According to a fifth aspect of the present invention, there is provided an audio apparatus using at least a part of the adaptive sound quality volume control apparatus or the DSP according to any one of the first to fourth aspects, and a high-performance audio apparatus. Can be realized.

According to a sixth aspect of the present invention, there is provided a loudspeaker system including the adaptive sound quality volume control device or the DSP according to any one of the first to fourth aspects, and a high-performance loudspeaker system can be realized. it can.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows a configuration of a first embodiment of the present invention, in which a maximum value is provided between a sound source signal analyzing unit 311 and a compensation amount calculating unit 305 in the conventional example shown in FIG. A detection means and a maximum value holding means are provided. In FIG. 1, 101 is a sound source such as a CD player, cassette tape, radio, or announcement, 102 is a microphone, 103 is a microphone signal analyzing means, 111 is a sound source signal analyzing means for calculating a level of each sound source signal in each frequency band, 112 is a maximum value detection means, 113 is a maximum value holding means, 104 is a noise signal calculation means, 105 is a compensation amount calculation means, 106 is an adjustment amount update means, 107 is a frequency characteristic control means such as an equalizer, and 108 is a volume control. Etc., 109 is an amplifier, 110 is a speaker, 111 is a sound source signal analyzing means, 112 is a maximum value detecting means, and 113 is a maximum value holding means. Reference numeral 114 denotes a control amount calculation unit, which is the microphone signal analysis unit 103, the noise signal calculation unit 104, the compensation amount calculation unit 105, the adjustment amount update unit 106, the sound source signal analysis unit 111, the maximum value detection unit 112, and the maximum value holding unit. It comprises means 113.

Next, the operation of the first embodiment of the present invention configured as described above will be described. In FIG. 1, frequency characteristics of a sound source signal such as an announcement and a sound source output from a sound source 101 such as a CD are adjusted by changing gains of a plurality of frequency bands by a frequency characteristic adjustment unit 107 such as an equalizer, and a volume and the like are adjusted. The volume is adjusted by the volume adjusting means 108 of the amplifier 109.
And is emitted to the space by the speaker 110. The output signal of the sound source 101 is also input to a sound source signal analysis unit 111, in which the sound source signal level for each of one or more frequency bands is analyzed at regular time intervals. This is an input to the detecting means 112. The maximum value detection means 112 determines the maximum value of the output of the sound source signal analysis means 111 for each time interval longer than the analysis time interval of the sound source signal analysis means 111, for example, between 1 second and 10 seconds. Detected for each frequency band, and outputs the maximum value to the maximum value holding means 113 at each maximum value detection time interval. The maximum value holding means 113
The held maximum value is output at regular time intervals, and becomes one input to the compensation amount calculation means 105.

In the space where the speaker 110 is installed, when the microphone 102 detects noise near the place where the sound output from the speaker 110 is received or at a high correlation with the ambient noise at the listening place, the signal becomes The microphone signal level of one or more frequency bands is analyzed by the microphone signal analysis unit 103 at regular time intervals, and is input to the other input of the noise signal detection unit 104. Since the microphone 102 often includes a sound source signal being reproduced or loudspeaked together with the ambient noise, the noise signal calculating means 104 calculates the level of the microphone signal calculated by the microphone signal analyzing means 103 for each frequency band. By subtracting the sound source signal level calculated by the sound source signal analyzing means 111, only the noise signal component level is calculated. When calculating the noise signal level by subtracting the sound source signal level, the noise signal level is calculated in consideration of the current control state, that is, the adjustment amounts of the frequency characteristic adjustment unit 107 and the volume adjustment unit 108. The compensation amount calculation means 105 calculates the compensation amount at regular time intervals using the maximum value of the sound source signal level held in the maximum value holding means 113.

The compensation amount updating means 106 integrates the output signal of the compensation amount calculating means 105, uses an average or LPF,
The adjustment amounts of the frequency characteristic adjustment unit 107 and the volume adjustment unit 108 are smoothly updated by other methods,
The sound quality and volume of the sound source signal are changed by the frequency characteristic adjusting unit 107 and the volume adjusting unit 109.

As described above, according to the first embodiment of the present invention, by providing the sound source signal analyzing means, the maximum value detecting means, and the maximum value holding means, it is possible to analyze the output of the sound source signal at a predetermined time interval. Since the maximum value is detected at a time interval longer than the analysis time interval and the compensation value is calculated using the maximum value, even if the ambient noise exists or the characteristics of the ambient noise change, the ambient noise is reduced. This has the effect that the sound source can be reproduced so that it can be heard at the same loudness as when there is no sound, does not react sensitively to the fluctuation of the sound source signal, and the sound source signal can be reproduced naturally in terms of audibility without fluctuation.

(Embodiment 2) FIG. 2 shows a configuration of a second embodiment of the present invention. The maximum value detecting means 112 and the maximum value holding means 113 in the first embodiment shown in FIG. The maximum value updating means 114 is provided between them, and the other configuration is the same as that of the first embodiment.

Next, the operation of the second embodiment of the present invention configured as described above will be described. In FIG. 2, the operation is the same as that described in the first embodiment, except for the output from the maximum value detection unit 212 to the maximum value holding unit 213. The maximum value detection means 212 outputs the maximum value every time the maximum value is detected even within the maximum value detection time interval while detecting the maximum value. The maximum value updating means 214 outputs the maximum value to the maximum value holding means 213 at every maximum value detection time interval, but holds the previously output maximum value and sends the maximum value from the maximum value detection means 212 to the maximum value detection time interval. If the output maximum value is larger than the previous maximum value, the maximum value is immediately output to the maximum value holding means 213 and held regardless of the maximum value detection time interval. Therefore, when the sound source signal suddenly increases, for example, when switching from BGM to an announcement, the maximum value can be updated without waiting for the maximum value detection time interval. Followability can be improved.

As described above, according to the second embodiment of the present invention, by providing the maximum value updating means, when the sound source signal suddenly increases, the maximum value can be obtained without waiting for the maximum value detection time interval. Because it can be updated, it does not respond sensitively to fluctuations in the sound source signal, and can reproduce the sound source signal naturally without fluctuation, and when the sound source characteristics change greatly, such as when switching from BGM to an announcement. Has the effect that the follow-up performance can be improved.

[0025]

As described above, according to the present invention, by providing the sound source signal analyzing means, the maximum value detecting means and the maximum value holding means, the output obtained by frequency-analyzing the sound source signal at the first time interval can be analyzed at the analysis time interval. A maximum value is detected at a longer second time interval, and the maximum value is detected by the noise signal calculation means.
The amount of compensation is calculated using the noise signal level, so that even if there is ambient noise or the characteristics of the ambient noise change, it can be heard at the same loudness as when there is no ambient noise. It is possible to obtain an effect that the sound source signal can be reproduced naturally and without any fluctuation, and does not fluctuate sensitively to the fluctuation of the sound source signal.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an adaptive sound quality volume control device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic block diagram of an adaptive sound quality volume control device according to a second embodiment of the present invention.

FIG. 3 is a schematic block diagram of a conventional adaptive sound quality volume control device 101, 201, 301 sound sources 102, 202, 302 microphones 103, 203, 303 microphone signal analysis means 104 204, 304 noise signal calculation means 105, 205, 305 compensation Amount calculating means 106, 206, 306 Adjustment amount updating means 107, 207, 307 Frequency characteristic adjusting means 108, 208, 308 Volume adjusting means 109, 209, 309 Amplifiers 110, 210, 310 Speakers 111, 211, 311 Sound source signal analyzing means 112, 212 Maximum value detecting means 113, 213 Maximum value holding means 114, 215, 312 Control amount calculating means 214 Maximum value updating means

Continuation of front page (56) References JP-A-5-37270 (JP, A) JP-A-56-16922 (JP, A) JP-A-58-13007 (JP, A) JP-A-6-334459 (JP, A) , A) JP-A-7-193526 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H03G 9/00 H03G 5/16

Claims (6)

(57) [Claims] 1. A signal level of a sound source signal for each frequency band.
Sound source signal analysis means for analyzing and outputting at every first time interval, and a signal for each frequency band of ambient noise input from a microphone.
The signal level is analyzed and output at each of the first time intervals.
From the output of the microphone signal analyzing means.
Noise signal level by subtracting the output of the sound source signal analysis means
And noise signal calculating means for detecting a maximum value detection for detecting a maximum value of the output of the sound source signal analyzing means second time interval longer than the first time interval in the sound source signal analyzing means for each of said frequency bands and the maximum value holding means for holding the unit, the maximum value detected <br/> by said maximum value detecting means, said maximum
The maximum value held by the value holding means and the noise signal calculating means
In adaptive tone volume control device including a control amount calculating means and a compensation amount calculating means for calculating a compensation amount for compensating the circumferential囲騒sound by using the detected noise signal level. 2. The signal level of a sound source signal for each frequency band
Sound source signal analysis means for analyzing and outputting at every first time interval, and a signal for each frequency band of ambient noise input from a microphone.
The signal level is analyzed and output at each of the first time intervals.
From the output of the microphone signal analyzing means.
Noise signal level by subtracting the output of the sound source signal analysis means
And noise signal calculating means for detecting a maximum value of the output of the sound source signal analyzing unit by the second time interval longer than the first time interval and detects for each of the frequency bands in the sound source signal analyzing means, a maximum value detecting means for detecting a maximum value of more than a certain level even in the maximum value detection time interval, holds the maximum value detected by said maximum value detecting means, the maximum value detection time interval from said maximum value detecting means If the maximum value output without depending on the maximum value is larger than the currently held maximum value, the maximum value updating means for updating to the maximum value, and the maximum value for holding the maximum value output from the maximum value updating means. Value holding means, and the maximum value held by the maximum value holding means and the noise signal level detected by the noise signal calculating means.
Adaptive tone volume control device including a control amount calculating means and a compensation amount calculating means for calculating a compensation amount for compensating the circumferential囲騒sound with the bell. 3. An adaptive sound quality volume control device in which the control amount calculating means in the adaptive sound quality volume control device according to claim 1 or 2 is realized by software. 4. A DSP (Digital Signal Processor) using the control amount calculating means in at least a part of the adaptive sound quality volume control device according to claim 1. 5. An audio device using at least a part of the adaptive sound quality volume control device or DSP according to claim 1. 6. A loudspeaker system including the adaptive sound quality volume control device or the DSP according to claim 1.