JPH10173457A - Audio system and volume control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically control the volume of a control sound source so that an extreme difference from the volume of non-control sound source is not felt when listening. SOLUTION: In this audio system having an adaptive equalizer function to match an audio signal at an observing point in a control band with a target signal, a driving signal (white noise signal) to be inputted to the non-control sound source 60 is defined as an input signal, and the detected signal in the observing point is defined as an output signal. The average energy of signal components in the non-control band of each signal is computed by an average power computing part 74, the gain Gavr of signal transmission system from the non-control sound source 60 to the observing point (the point of a microphone 54) is computed from the ratio of these two average energies in a gain calculating/setting part 75, and the gain Gavr is set to a target signal output part 52 forming the adaptive equalizer of the control band as a target gain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio apparatus and a method for adjusting the volume of the audio apparatus, and more particularly to an audio apparatus having an adaptive equalizer function for controlling an audio signal of a specific band (control band) to be a target signal. The present invention relates to an audio device for making a sound volume of a band substantially equal to a sound volume of a non-control band, and a sound volume adjusting method thereof.

[0002]

2. Description of the Related Art A vehicle interior is a closed narrow space.
Therefore, reflection occurs in a short time, and the sound waves interfere with each other, so that the transfer characteristic to the listening point becomes very complicated. In addition, since music or the like is listened to in an asymmetrical place, the transfer characteristics from the left and right speakers will be greatly different. There is a demand for an audio device for removing such adverse effects in the vehicle interior and improving acoustic characteristics in the vehicle interior. For this reason, a control has been proposed in which a plurality of points (control points) in a reproduction space have desired characteristics including amplitude and phase characteristics using an adaptive equalizer.

FIG. 5 is a diagram showing the basic configuration of an adaptive equalization system. Reference numeral 1 denotes an audio source (tuner, tape deck, CD player, etc.) for outputting an audio signal x (n);
Is set to a target response characteristic (impulse response characteristic) H, an audio signal x (n) is input, and a target signal d (n)
, A microphone for detecting a sound at a listening position (observation point) in the vehicle interior acoustic space, 5 a detected music signal d ^ (n) and a target signal d output from the filter 2 a calculation unit for calculating an error e (n) with respect to (n); an adaptive signal processing device 6 for generating a signal y (n) such that the power of the error e (n) is minimized; The speaker emits a sound corresponding to (n) to the vehicle interior acoustic space 8.

The target response setting section 2 has a delay characteristic of the time t, where t is a signal delay time from the output end of the audio source 1 to the microphone 4 via the speaker 7. , Flat characteristics (gain 1 characteristics) are set in all audio frequency bands. That is, the target response setting unit 2 is provided with a flat frequency characteristic of a gain 1 as shown in FIG. 6A and a characteristic in which the impulse response has a delay time t as shown in FIG. 6B. You. The target response setting unit 2 sets the coefficient of the tap corresponding to the delay time t of the FIR digital filter to 1
And by setting the coefficients of the other taps to zero. For example, assuming that one sampling time is τ and the delay time is t, this can be realized by setting the coefficient of the t / τth tap of the FIR digital filter to 1 and setting the other coefficients to 0.

[0005] The adaptive signal processing device 6 generates an audio signal x.
(n) is input as a reference signal and the operation unit 5
The error signal e (n) output from the
The adaptive signal processing is performed so that the signal power is minimized, and the signal y (n) is output. The adaptive signal processing device 6 includes an adaptive signal processing unit (LMS) 6a, an adaptive filter 6b having a FIR type digital filter configuration, and a propagation characteristic of a sound propagation system from the speaker 7 to the listening position for the reference signal x (n) ( Transfer function) C ^ is convolved to generate a reference signal (filtered reference signal) r (n) for use in adaptive signal processing.

The adaptive signal processor 6a receives the error signal e (n) at the listening position and the reference signal r (n) for adaptive signal processing input via the signal processing filter 6c, and uses these signals to listen. The adaptive signal processing is performed so that the music signal d ^ (n) at the position becomes equal to the target signal d (n), and the coefficient of the adaptive filter 6b is determined. For example, the adaptive signal processing unit 6a determines the coefficient of the adaptive filter 6b according to the well-known LMS (Least Mean Square) adaptation algorithm so that the power of the error signal e (n) is minimized. The adaptive filter 6b subjects the audio signal x (n) to digital filter processing according to the coefficient determined by the adaptive signal processing unit 6a, and outputs a signal y (n). Therefore, if the coefficients of the adaptive filter 6b converge so that the power of the error signal e (n) is minimized by the adaptive signal processing, the music signal d ^ (n) becomes equal to the target signal d (n) at the listening position. That is, an effect is obtained that the same sound can be heard as when the sound is heard in an ideal space of the transfer characteristic H (the frequency characteristic is flat) set in the target response setting section 2.

[0007] As shown in FIG.
It is composed of a tap FIR digital filter. For example, the input signal is sequentially delayed by one sampling time (N−
1) delay elements DL ₁ , DL ₂ ... DL _N−1, and coefficients w ₀ (n), w ₁ (n), w ₂ (n).
_N multiplying units ML ₀ , ML ₁ ,... M for multiplying _N−1 (n)
L _N−1 and the adders AD ₀ and A that sequentially add the outputs of the multipliers
It is implemented by D ₁ ··· AD _N-1. That is, the current time n
The reference signal in Ts x (n), w ₀ the coefficients of the multipliers at the time _{(n), w 1 (n} ), w 2 (n) ··· w N-1 (n), the output signal y (n), the adaptive filter 6b is given by

[0008]

(Equation 1) And outputs a signal y (n).

[0009] As shown in FIG.
Type digital filter.
(M-1) delay elements delayed by the next one sampling time
DL ₁, DL_Two... DL_M-1And the coefficient c for each delay element output
₀, C₁, C_Two... c_M-1Multiplication units ML for multiplying₀, M
L₁, ... ML_M-1And the addition of
Arithmetic part AD₀, AD₁... AD_M-1Is realized. coefficient
c₀, C₁, C_Two... c_M-1Is the secondary sound propagation system (viewed from the speaker)
Determined to simulate the propagation characteristics of the system up to the measurement point)
I have. The reference signal at time n · Ts is output as x (n),
If filter (filtered X signal) is r (n), filter 6c
formula

[0010]

(Equation 2) And outputs a filtered X signal r (n).

The adaptive signal processing section 6a outputs the adaptive filter 6 at the next time (n + 1) · Ts after one sampling time Ts.
coefficient w ₀ (n + 1), w ₁ (n + 1), w ₂ (n + 1)... w _N−1 (n +
1) is converted to coefficients w ₀ (n), w ₁ (n), w at the current time n · Tτ.
₂ (n)... W _N−1 (n), an error signal e (n), and a filtered X signal r (n) are determined by the following coefficient update formula.

[0012]

(Equation 3)

However, the j-th filter coefficient update equation is given by w _j (n + 1) = w _j (n) + αr (n-j + 1) e (n) (4). In equation (3), (n) is the value at the current sampling time, (n + 1) is the value after one sampling time, and (n-1) is 1
The value before the sampling time, (n−2) means the value two sampling times before,.... Α is a constant that determines a step of updating the coefficient of the adaptive filter, and is set to an appropriate value. In the processing by the filtered XLMS adaptive algorithm, the operations of the above equations (1) to (3) are performed within one sampling time, and a signal y (n) is output.

As described above, the adaptive signal processing section 6a receives the error signal e (n) at the listening position and the adaptive signal processing reference signal r (n) input via the filter 6c, and receives these signals. The music signal d at the listening position using
The coefficient of the adaptive filter 6b is determined by performing adaptive signal processing so that ^ (n) becomes equal to the target signal d (n). The adaptive filter 6b subjects the audio signal x (n) to digital filter processing according to the coefficient determined by the adaptive signal processing unit 6a, and outputs a signal y (n). Therefore, if the coefficient of the adaptive filter 6b converges to a predetermined value so that the power of the error signal e (n) is minimized by the adaptive signal processing, the transfer characteristic H set in the digital filter 2 at the listening position.
An effect equivalent to listening to a sound in a space having the above can be obtained.

In the adaptive equalization system, it is natural to control the entire band as described above. But,
There is a problem that a huge amount of calculation is required, and if the processing is to be performed in real time, several hundred DSPs are required. Therefore, only a specific frequency band, for example, 200H
In order to improve the reproduction quality of bass sound below z, an adaptive equalizer that targets only the bass range has been proposed. FIG. 9 is a configuration diagram of such an adaptive equalizer, and the same parts as those in FIG. 5 are denoted by the same reference numerals. The difference from FIG. 5 is that
A low-pass filter (LPF) 9 that passes a low frequency range is provided at a stage subsequent to the audio source 1, and its output is input to the target response setting unit 2 and the adaptive signal processing device 6. A second speaker 10 that emits audio sound to the vehicle interior acoustic space 8 is provided, and a delay unit 11 that delays an audio signal is provided in a stage preceding the second speaker 10. When the signal delay time reaching the microphone 4 via the speaker 7 is t and the signal delay time from the second speaker 10 to the microphone 4 is td, the time Δt (= t−td) is given to the delay unit 11. The point is that the audio signal of the entire audible band is input to the second speaker 10 after being delayed by Δt.

According to this adaptive equalizer, the adaptive filter 6b becomes an inverse filter of the reproduction system (the transfer characteristic from the speaker 7 to the microphone position) only in the low frequency range (specific band) limited by the low-pass filter 9, and Signal d
It operates to become (n). Then, by controlling only the specific band, the amount of calculation can be reduced as compared with the adaptive equalization system of FIG.

[0017]

By the way, in the adaptive equalizer which targets only the specific band in FIG. 9, the audio signal of the specific band (control band) output from the first speaker 7 and the second speaker 10 If the volume levels at the observation points of the audio signals in the entire audible band output from are not the same, a sense of incongruity is given to the listener. That is, it is necessary to adjust the volume of the control sound source (first speaker 7) so that an extreme difference in the sense of hearing from the volume of the non-control sound source (second speaker 10) is not felt. So conventionally,
A technician having specialized knowledge examines a transfer function of a signal transmission system in a non-control band in which a drive signal of the second speaker 10 is an input signal and an output of the microphone 4 is an output signal.
Based on the result, the volume of the control sound source (the first speaker 7) was manually adjusted. However, such a method requires expensive equipment, requires specialized knowledge for proper volume adjustment, and is troublesome for adjustment, and difficult for ordinary users to adjust. there were.

As described above, an object of the present invention is to provide an audio apparatus capable of automatically adjusting the volume level of a control band and the volume level of a non-control band at an observation point so as to substantially coincide with each other. It is another object of the present invention to provide an audio device capable of adjusting the volume of a control band and the volume of a non-control band to a generally balanced level. Another object of the present invention is to improve the connection between the frequency characteristics of the control band and the frequency characteristics of the non-control band so that a large dip or peak does not occur at the connection portion.

[0019]

According to the present invention, a drive signal to be input to a non-controlled sound source is used as an input signal.
The signal detected at the observation point is used as an output signal, and the average energy of the signal components in the non-control band or adjacent non-control band or the entire audible band of each signal is calculated, and non-control is performed based on the ratio of the obtained two average energies. This is achieved by a volume adjustment method in which a gain of a signal propagation system from a sound source to an observation point is calculated, and the gain is set as a target gain in a target response setting unit of a control band.

According to the present invention, there is provided a white noise generator for generating a white noise signal and inputting the signal to a second speaker which is an uncontrolled sound source, and extracts a signal component in a non-control band from the white noise signal. Filter, a second filter for extracting a signal component in a non-control band from a white noise signal detected at an observation point, and an average energy of signals output from the first and second filters, respectively. An average energy calculating unit that calculates a gain of a signal propagation system from the second speaker to the observation point based on a ratio of the obtained two average energies, and sets the gain as a target gain in a target response setting unit of a control band. This is achieved by an audio device comprising the means.

Further, according to the present invention, there is provided a white noise generating unit for generating a white noise signal and inputting the white noise signal to a second speaker which is an uncontrolled sound source, a predetermined frequency width adjacent to a control band from the white noise signal. A first filter for extracting and outputting a signal component in the non-control band of the second filter, a second filter for extracting a signal component of the adjacent non-control band from the white noise signal detected at the observation point, and a first and a second filter An average energy calculation unit that calculates the average energy of the signal output from the second unit, calculates the gain of the signal propagation system from the second speaker to the observation point based on the ratio of the obtained two average energies, and sets the gain to the control band. This is achieved by an audio apparatus provided with a means for setting a target gain in a target response setting section of (1).

Further, according to the present invention, there is provided a white noise generating section for generating a white noise signal and inputting the white noise signal to a second speaker which is an uncontrolled sound source. An average energy calculation unit that calculates an average energy of each of the white noise signals detected at the point, calculates a gain of a signal propagation system from the second speaker to the observation point based on a ratio of the obtained two average energies, Is set in the target response setting section of the control band as a target gain.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) First Embodiment FIG. 1 is a configuration diagram of an audio apparatus according to a first embodiment of the present invention. In the drawing, reference numeral 51 denotes an audio source (tuner, tape deck, CD player, etc.) for outputting an audio signal x (n), 52 denotes a target response characteristic (impulse response characteristic) H, and an audio signal x (n) is input. A target response setting unit for outputting a target signal d (n), a microphone 54 for detecting a sound at a listening position (observation point) in the vehicle interior acoustic space, and a reference numeral 55 for the detected music signal d ^ (n) and the target. An arithmetic unit for calculating an error e (n) from the target signal d (n) output from the response setting unit 52. The arithmetic unit 56 generates the signal y (n) so that the power of the error e (n) is minimized. An adaptive signal processing unit (LMS) 56a and an adaptive filter 5
6b and a filter 56c for generating a reference signal r (n) used for adaptive signal processing. 57 is the signal y (n)
Is a first loudspeaker (control sound source) that emits a sound corresponding to the above to the vehicle interior acoustic space 58.

Reference numeral 59 denotes a low-pass filter, which passes a signal component in a low frequency band (control band) of a specific band, for example, 200 Hz or less, and inputs it to the target response setting unit 52 and the adaptive signal processing device 56. A second speaker (non-control sound source) 61 which receives the audio signal and emits the audio sound to the vehicle interior acoustic space 58, 61 is a delay device for delaying the audio signal of the entire audible band by a predetermined time Δt. The signal delay time of a specific band from the output end of the audio source 51 to the microphone 54 via the first speaker 57 is t, and the signal delay time of the entire audible band from the second speaker 60 to the microphone 54 is td. At this time, Δt (= so that the audio sound in the specific band and the audio sound in the entire audible band reach the observation point at the same time.
The delay time of t−td) is set in the delay unit 11. The above configuration is the same as that of the conventional adaptive equalizer shown in FIG. 9, and the operation of each part is as described in detail with reference to FIGS.

Reference numeral 71 denotes a white noise generator that outputs a white noise signal (white noise signal) having a constant level over the entire audible band, and 62 denotes a switch that selects one of the audio signal and the white noise signal output from the delay unit 61. When the volume is adjusted, a white noise signal is selected and output, and after the volume is adjusted, the audio signal from the delay unit 61 is selectively output. 72 is a first high-pass filter (HPF) for extracting and outputting a signal component v _H (n) in a band other than the control band (non-control band) from the white noise signal, and 73 is a microphone 54 at the observation point during automatic volume adjustment. Is a second high-pass filter (HPF) that extracts and outputs a signal component d ′ _H (n) in a non-control band from the white noise signal detected by the above.

Reference numeral 74 denotes an average energy E [v _{H of the} signals v _H (n) and d ′ _H (n) output from the first and second filters 72 and 73.
(n) ² ] and E [d ′ _H (n) ² ]

(Equation 4) Are the average power calculation units respectively calculated by still,
The value obtained by dividing the equations (5) and (6) by N can be used as the average energy.

75 is the two average energies E obtained.
The ratio of [d ′ _H (n) ² ] and E [v _H (n) ² ] is defined as the gain of the signal propagation system from the second speaker 10 to the observation point, and the following equation Gavr = ｛E [d ′ _H ( n) ² ] / E [v _H (n) ² ]｝ ^1/2 (7), and calculates the average gain Gavr, and uses the gain Gavr as the gain of the transfer characteristic set in the target response setting unit 52. It is a calculation / setting unit.

At the time of volume adjustment, an audio signal is not output from the audio source 51 and a white noise signal generator 71 is driven to generate a white noise signal.
The switch 62 selects the white noise signal and inputs it to the second speaker 60 to drive the second speaker 60. In this state, the second speaker (uncontrolled sound source) 60
Microphone 54 at the observation point with the white noise signal
Are respectively converted into first and second white noise signals.
And outputs the audio signal components v _H (n) and d ′ _H (n) in the non-control band.
Note that the cut-off frequencies of the first and second high-pass filters are made to match the cut-off frequency of the low-pass filter 59.

Next, the average power calculator 74 outputs the signals v _H (n), d ′ output from the first and second filters 72 and 73.
The average energy of _H (n) E [v _H (n) ² ] and E [d ′ _H (n) ² ]
The calculated values are calculated by the equations (5) and (6) and input to the gain calculating / setting unit 75. The gain calculation / setting unit 75 calculates the average energy E
When [d ′ _H (n) ² ] and E [v _H (n) ² ] are input, the average gain Gavr of the signal propagation system from the second speaker 10 to the observation point is calculated by Expression (7). , The average gain Gavr is set in the target response setting section 52. With the above, the sound volume adjustment ends. Thereafter, if the output signal of the delay unit 61 is selected by the switch 62 and the audio signal is output from the audio source 51, the adaptive equalizer control in the control band is performed as described with reference to FIG. Becomes equal to the target signal. At this time, since the gain Gavr set in the target response setting section 52 is equal to the gain of the non-control band from the second speaker 60 to the observation point, the volume of the control band and the volume of the non-control band at the observation point are reduced. It is almost equal.

FIG. 2 is an explanatory diagram for explaining the effect of the present invention. FIG. 2A is a frequency characteristic diagram of a signal propagation system from the second speaker 60 to the observation point, and a frequency band from 0 to fc. Is the control band, and the frequency fc or higher is the non-control band,
The level indicated by the dotted line is the average gain of the non-control band from the second speaker 60 to the observation point. FIG. 2B shows a frequency characteristic of the observation point when the detected audio signal at the observation point is controlled by the adaptive equalizer control so as to substantially coincide with the target signal. As is clear from this figure, since the gain of the control band at the observation point and the gain of the non-control band are equal,
The volume of the control band and the volume of the non-control band are substantially the same.

(B) Second Embodiment FIG. 3 is a block diagram of an audio apparatus according to a second embodiment of the present invention. The second embodiment of FIG. 3 differs from the first embodiment in that the first and second high-pass filters 72 and 72 of the first embodiment are different from each other.
73 is replaced by bandpass filters 81 and 82. In the first embodiment, when the level on the high frequency side of the non-control band is large, the average gain Gavr becomes large, and the connection between the frequency characteristic of the control band and the frequency characteristic of the non-control band becomes poor as shown in FIG. , A relatively large dip DP occurs. Therefore, in the second embodiment, as shown in FIG. 2C, the average gain of the signal propagation system in the non-control band (adjacent non-control band) adjacent to the control band (0 to fc) is Gav.
r ′ and calculates the average gain Gavr ′ in the target response setting unit 5.
It is set to 2. The frequency width of the adjacent non-control band is, for example, the same width as the control band, and is fc to 2fc.

At the time of volume adjustment, an audio signal is not output from the audio source 51 and a white noise signal is generated by driving a white noise signal generator 71.
The switch 62 selects the white noise signal and inputs it to the second speaker 60 to drive the second speaker 60. In this state, the first and second band-pass filters 81 and 82 filter a white noise signal which is a drive signal of the second speaker (uncontrolled sound source) 60 and a white noise signal detected by the microphone 54 at the observation point, respectively. Then, the audio signal components v _H (n) and d ′ _H (n) of the adjacent non-control band are output.

Next, the average power calculator 74 outputs the signals v _H (n), d ′ output from the first and second filters 81 and 82.
The average energy of _H (n) E [v _H (n) ² ] and E [d ′ _H (n) ² ]
The calculated values are calculated by the equations (5) and (6) and input to the gain calculating / setting unit 75. The gain calculation / setting unit 75 calculates the average energy E
[d _'H (n) ^2], the ^{_{E [v H (n) 2}} ] is input, (7) the average gain Gavr signal propagation system to the observation point from the second speaker 10 by equation' calculated Then, the average gain Gavr 'is set in the target response setting section 52. With the above, the sound volume adjustment ends.

Thereafter, when the output signal of the delay unit 61 is selected by the switch 62 and the audio signal is output from the audio source 51, the adaptive equalizer control in the control band is performed as described with reference to FIG. The detected audio signal matches the target signal. At this time, the gain Gavr ′ set in the target response setting section 52 is
Since the gain is equal to the gain of the adjacent non-control band from the second speaker 60 to the observation point, the volume of the control band and the volume of the non-control band at the observation point are substantially equal. Further, since the average gain Gavr 'of the adjacent non-control band is smaller than the average gain Gavr of all the non-control bands, the dip DP becomes small as shown in FIG. The connection of the frequency characteristics is improved, and the sense of incongruity in hearing can be improved.

(C) Third Embodiment FIG. 4 is a block diagram of an audio apparatus according to a third embodiment of the present invention. The difference from the first embodiment of FIG. 1 is that first and second filters 72 and 73 are provided. Is the point that was deleted. In the third embodiment,
Average gain Gavr ″ of signal propagation system in all audible sound bands
And calculates the average gain Gavr ″ as the target response setting unit 52
Set to.

When adjusting the volume, the audio signal is not output from the audio source 51, and the white noise signal generator 71 is driven to generate a white noise signal.
The switch 62 selects the white noise signal and inputs it to the second speaker 60 to drive the second speaker 60. In this state, the white noise signal which is the drive signal of the second speaker (uncontrolled sound source) 60 and the white noise signal detected by the microphone 54 at the observation point are respectively denoted by v _H (n) and d ′.
_It is input to the average power calculation unit 74 as _H (n).

The average power calculating section 74 calculates these signals v
_H(n), d ′_H(n) average energy E [v_H(n)^Two], E [d '_H(n)
^TwoIs calculated by the formulas (5) and (6) to obtain the gain calculation / setting unit 75.
To enter. The gain calculation / setting unit 75 calculates the average energy.
 E [d ′_H(n)^Two], E [v_H(n) ^Two] Is input, the equation (7)
Of the signal propagation system from the second speaker 10 to the observation point.
Calculates the average gain Gavr ″ and sets the average gain Gavr ″ as the target.
This is set in the response setting unit 52. This completes volume adjustment.
Complete. Thereafter, the output signal of the delay unit 61 is
Select the audio signal from the audio source 51
If output, it is appropriate for the control band as described in FIG.
Equalizer control is performed, and the detected audio
The audio signal comes to coincide with the target signal. At this time,
The gain Gavr ″ set in the target response setting section 52 is
Average gain of all audible bands from speaker 60 to observation point
Control band at the observation point
The volume and the volume of the non-control band become almost equal.

(D) Modifications Although the first to third embodiments have been described above, the method for setting the gain in the target response setting section 52 depends on the target vehicle, the preference of the user, or the environment. It depends. Therefore, the average gains Gavr, Gavr ′, Gavr ″ calculated in each embodiment are set in the memory, and a predetermined average gain is selected according to the user's preference and set in the target response setting unit 52. Although the present invention has been described with reference to the embodiments, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0039]

As described above, according to the present invention, the uncontrolled sound source (the second
The driving signal to be input to the loudspeaker is used as an input signal, the signal detected at the observation point is used as an output signal, and the average energy of the signal component in the non-control band or adjacent non-control band or the entire audible band of each signal is calculated. Since the gain of the signal propagation system from the uncontrolled sound source to the observation point is calculated based on the ratio of the obtained two average energies, and the gain is set as the target gain of the control band,
It is possible to automatically adjust the volume of the control sound source so that there is no extreme difference in hearing from the volume of the non-control sound source. Be reduced. In addition, even a general user without specialized knowledge can easily and accurately adjust the volume of the control sound source.

According to the present invention, a white noise generator for inputting a white noise signal to a second speaker as a non-control sound source, and a first filter for extracting a signal component in a non-control band from the white noise signal and outputting the extracted signal component A second filter for extracting a signal component in a non-control band from a white noise signal detected at an observation point, an average energy calculation unit for calculating average energy of signals output from the first and second filters, respectively. The second is calculated by the ratio of the two average energies
Means for calculating the gain of the signal propagation system from the loudspeaker to the observation point, and using the gain as the gain of the transfer characteristic set in the target response setting unit of the control band, is provided in the audio device. Can be adjusted so that the volume level of the control band and the volume level of the non-control band substantially coincide with each other, and the volume of the control band and the volume of the non-control band can be adjusted to a balanced level as a whole.

Further, according to the present invention, a white noise generator for inputting a white noise signal to a second speaker as a non-control sound source, a signal in a non-control band having a predetermined frequency width adjacent to the control band from the white noise signal. A first filter that extracts and outputs a component, a second filter that extracts a signal component in an adjacent non-control band from a white noise signal detected at an observation point, and a signal that is output from the first and second filters. An average energy calculation unit that calculates an average energy, calculates a gain of a signal propagation system from the second speaker to the observation point based on a ratio of the obtained two average energies,
Since the audio device is provided with a means for setting the gain to the gain of the transfer characteristic set in the target response setting unit of the control band, the volume level of the control band at the observation point and the volume level of the non-control band automatically match. In addition, the connection between the frequency characteristics of the control band and the frequency characteristics of the non-control band can be improved, and a large dip or peak can be prevented from occurring at the connection portion.

Further, according to the present invention, a white noise generator for inputting a white noise signal to a second speaker, which is an uncontrolled sound source, a white noise signal input to the speaker and a white noise signal detected at the observation point An average energy calculator for calculating the average energy of the signal, respectively,
Means for calculating the gain of the signal propagation system from the second speaker to the observation point based on the ratio of the two average energies, and using the gain as the gain of the transfer characteristic set in the target response setting unit of the control band in the audio device. Since it is provided, the volume level of the control band and the volume level of the non-control band at the observation point can be automatically adjusted to substantially match, and furthermore, the connection between the frequency characteristics of the control band and the frequency characteristics of the non-control band is improved, Dip and peak in the connected portion can be made smaller.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an audio device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an effect of the present invention.

FIG. 3 is a configuration diagram of an audio device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of an audio device according to a third embodiment of the present invention.

FIG. 5 is a basic configuration diagram of an adaptive equalization system.

FIG. 6 is an explanatory diagram of characteristics set in a target response setting unit.

FIG. 7 is a configuration diagram of an adaptive filter.

FIG. 8 is a configuration diagram of a filter that generates a reference signal for adaptive processing (filtered reference signal).

FIG. 9 is an adaptive equalizer that targets only a specific band.

[Explanation of symbols]

 51 audio source 52 target response setting unit 54 microphone 55 arithmetic unit 56 adaptive signal processing device 57 first speaker 59 low-pass filter 60 second speaker 61 Delay unit 72, 73 High-pass filter 74 Average power calculation unit 75 Gain calculation / setting unit

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04R 3/00 310 H04R 3/00 310

Claims (4)

[Claims] 1. A filter that passes a control band component of an audio signal, a predetermined transfer characteristic is set, a target response setting unit that convolves the transfer characteristic with the audio signal of the control band and outputs a target signal, Means for outputting an error signal that is a difference from the audio signal detected at the observation point,
An audio signal in the control band and the error signal are input, adaptive signal processing is performed so that the power of the error signal is minimized, coefficients of an adaptive filter are determined, and the adaptive filter filters the audio signal in the control band. An adaptive signal processing device for applying and outputting an audio signal, a delay unit for delaying an audio signal by a set time Δt, a control sound source for receiving an audio signal output from the adaptive filter and emitting an audio sound to an acoustic space, and an output from the delay unit In the method for adjusting the volume of an audio device having an uncontrolled sound source that receives an audio signal to be input and emits an audio sound to an acoustic space, a drive signal input to the uncontrolled sound source is used as an input signal, and is detected at an observation point. Signals are output signals, and a predetermined frequency adjacent to the non-control band or control band of each signal Calculating the average energy of the signal component in the adjacent non-control band of the width or the entire audible band, and calculating the gain of the signal propagation system from the non-control sound source to the observation point by the ratio of the obtained two average energies; A volume adjustment method for an audio device, wherein a gain is a gain of a transfer characteristic set in the target response setting section. 2. A filter that passes a control band component of an audio signal, a predetermined transfer characteristic is set, a target response setting unit that convolves the transfer characteristic with the audio signal of the control band and outputs a target signal, and a target signal; Means for outputting an error signal that is a difference from the audio signal detected at the observation point,
An audio signal in the control band and the error signal are input, adaptive signal processing is performed so that the power of the error signal is minimized, coefficients of an adaptive filter are determined, and the adaptive filter filters the audio signal in the control band. An adaptive signal processing device for applying and outputting an audio signal, a delay unit for delaying an audio signal by a set time Δt, a control sound source for receiving an audio signal output from the adaptive filter and emitting an audio sound to an acoustic space, and an output from the delay unit An audio device having an uncontrolled sound source that receives an audio signal to be input and emits an audio sound to an acoustic space, a white noise generator that inputs a white noise signal to the uncontrolled sound source, A first filter for extracting a signal component, from a white noise signal detected at the observation point A second filter for extracting a signal component in a non-control band, an average energy calculating unit for calculating an average energy of each of signals output from the first and second filters, and non-control based on a ratio of the obtained two average energies. An audio apparatus comprising: means for calculating a gain of a signal propagation system from a sound source to an observation point, and using the gain as a gain of a transfer characteristic set in the target response setting unit. 3. A filter that passes a control band component of an audio signal, a predetermined transfer characteristic is set, a target response setting unit that convolves the transfer characteristic with the audio signal of the control band and outputs a target signal, and a target signal; Means for outputting an error signal that is a difference from the audio signal detected at the observation point,
An audio signal in the control band and the error signal are input, adaptive signal processing is performed so that the power of the error signal is minimized, coefficients of an adaptive filter are determined, and the adaptive filter filters the audio signal in the control band. An adaptive signal processing device for applying and outputting an audio signal, a delay unit for delaying an audio signal by a set time Δt, a control sound source for receiving an audio signal output from the adaptive filter and emitting an audio sound to an acoustic space, and an output from the delay unit An audio device having an uncontrolled sound source that receives an audio signal to be input and emits an audio sound to an acoustic space, a white noise generator that inputs a white noise signal to the uncontrolled sound source, A first filter for extracting and outputting a signal component in an adjacent non-control band having a predetermined frequency width; A second filter for extracting a signal component of an adjacent non-control band from a white noise signal detected at the observation point; and an average energy calculation for calculating average energies of signals output from the first and second filters, respectively. Means for calculating a gain of a signal propagation system from an uncontrolled sound source to an observation point based on a ratio of the obtained two average energies, and using the gain as a gain of a transfer characteristic set in the target response setting unit. An audio device, characterized in that: 4. A filter that passes a control band component of an audio signal, a predetermined transfer characteristic is set, a target response setting unit that convolves the transfer characteristic with the audio signal in the control band and outputs a target signal, and a target signal; Means for outputting an error signal that is a difference from the audio signal detected at the observation point,
An audio signal in the control band and the error signal are input, adaptive signal processing is performed so that the power of the error signal is minimized, coefficients of an adaptive filter are determined, and the adaptive filter filters the audio signal in the control band. An adaptive signal processing device for applying and outputting an audio signal, a delay unit for delaying an audio signal by a set time Δt, a control sound source for receiving an audio signal output from the adaptive filter and emitting an audio sound to an acoustic space, and an output from the delay unit An audio device having an uncontrolled sound source that receives an audio signal to be input and emits an audio sound to an acoustic space, a white noise generator that inputs a white noise signal to the uncontrolled sound source, a white noise signal that is input to a speaker And the average energy of the white noise signal detected at the observation point, respectively. An average energy calculation unit calculates a gain of a signal propagation system from an uncontrolled sound source to an observation point based on a ratio of the obtained two average energies, and calculates the gain and a gain of a transfer characteristic set in the target response setting unit. An audio device comprising means for performing: