JP4999766B2 - Active vibration noise reduction device - Google Patents

Description

  The present invention relates to an active vibration noise reduction apparatus that actively reduces vibration noise in a vehicle interior using an adaptive notch filter in a space such as the interior of a vehicle.

  Conventionally, in order to reduce the noise in the interior of an automobile, for example, there has been active noise control in which noise is reduced by generating a canceling sound (silenced sound) having a phase opposite to that of the noise from a speaker or the like to cause interference. It has been put into practical use.

  In the above practical application, a common configuration is that the signal amplification amplifier and the speaker are shared with the audio set, and a signal obtained by adding the audio signal and the canceling sound is output from the speaker.

  In recent years, genuine car audio with high sound quality has become widespread, and active noise control devices that share a sound field with car audio have been required to have no effect on the sound quality of the audio. It is coming.

FIG. 10 is a block diagram showing a configuration when an active vibration noise reduction apparatus using a conventional SAN type 1-tap adaptive notch filter is applied to an automobile.
As shown in FIG. 10, the SAN type 1-tap adaptive notch filter 1 includes a reference signal generation unit 1a including a control frequency calculation unit 1ac, a cosine wave generator 1aa, and a sine wave generator 1ab, and a first adaptation. Simulated signal generating means 1c composed of an adaptive notch filter 1b composed of a notch filter 1ba, a second adaptive notch filter 1bb and an adder 10, a simulated cosine wave signal generating means 1ca, and a simulated sine wave signal generating means 1cb. And a filter coefficient updating means 1d composed of a first coefficient updating means 1da and a second coefficient updating means 1db, and the SAN type 1-tap adaptive notch filter 1 and vibration noise that generates a canceling sound. A speaker 3 as canceling means, and a microphone 4 as error signal detecting means for detecting an error signal due to interference between noise and the canceling sound; An active vibration noise control system is configured.

Each of the above components operates as follows.
First, the control frequency calculation means 1ac calculates the frequency to be controlled based on the engine rotation signal obtained by detecting the engine speed from the engine pulse or the like.

  The cosine wave generator 1aa generates a cosine wave reference signal (reference cosine wave signal) based on the control frequency calculated by the control frequency calculation means 1ac. Similarly, the sine wave generator 1ab generates a sine wave reference signal (reference sine wave signal) based on the control frequency calculated by the control frequency calculation means 1ac.

  Next, the product of the reference cosine wave signal and the coefficient of the first adaptive notch filter 1ba and the product of the reference sine wave signal and the coefficient of the second adaptive notch filter 1bb are added by the adder 10 and output to the speaker 3 as a silenced signal. The speaker 3 outputs the sound deadening signal as a canceling sound into the vehicle interior.

  The microphone 4 detects the sum of the noise in the vehicle interior and the canceling sound output from the speaker 3, and uses it as an error signal to update the first coefficient updating means 1da and the second coefficient updating of the SAN type 1-tap adaptive notch filter 1. Output to means 1db.

Here, the coefficients of the first adaptive notch filter 1ba and the second adaptive notch filter 1bb are determined as follows.
The simulated cosine wave signal generating means 1ca uses the product of the reference cosine wave signal and the simulated cosine wave signal coefficient (a coefficient simulating the acoustic transfer characteristic from the speaker 3 to the microphone 4) as the simulated cosine wave signal, and the first coefficient updating means 1da. Output to. Similarly, the simulated sine wave signal generating means 1cb uses the product of the reference sine wave signal and the simulated sine wave signal coefficient (a coefficient simulating the acoustic transfer characteristic from the speaker 3 to the microphone 4) as the simulated sine wave signal as the second coefficient. Output to the update means 1db.

  Then, the first coefficient updating means 1da updates the coefficient of the first adaptive notch filter 1ba based on the error signal and the simulated cosine wave signal output from the microphone 4 so that the error signal is minimized by the least square method, Similarly, the second coefficient updating unit 1db updates the coefficient of the second adaptive notch filter 1bb based on the error signal output from the microphone 4 and the simulated sine wave signal so that the error signal is minimized by the least square method. .

  These processes are sequentially calculated by an arithmetic processing unit such as a microcomputer so that the canceling sound output from the speaker 3 based on the sound deadening signal corresponds to the vehicle interior noise that changes from moment to moment. By updating the coefficient of the first adaptive notch filter and the coefficient of the second adaptive notch filter, noise reduction in the vehicle interior is realized.

For example, Patent Document 1 is a document relating to a conventional one-tap active vibration noise reduction device of this type.
JP 2004-361721 A

  The active vibration noise reduction apparatus using the conventional SAN type 1-tap adaptive notch filter as described above is an adaptive notch filter as long as the acoustic transmission frequency characteristic is constant as the acoustic transmission characteristic including the speaker 3 to the microphone 4. Although the influence on the sound other than the control frequency component of 1b is very small, if there is a delay in the phase characteristic of the acoustic transfer frequency characteristic, the canceling sound from the SAN type 1-tap active vibration noise reduction device is not generated. It is known that the sound near the control frequency is increased. Further, it is known that the volume increase is proportional to the magnitude of the gain characteristic of the acoustic transmission frequency characteristic.

  Here, in an enclosed space such as in an automobile, the acoustic transfer frequency characteristic is not constant, and for example, as shown in FIG. 11, there is a peak dip in the gain characteristic and a delay in the phase characteristic. When the peak of the gain characteristic in the acoustic transfer characteristic is large, the phase characteristic delay near the frequency of the gain peak is also large.

That is, when the active vibration noise reduction apparatus using the conventional SAN type 1-tap adaptive notch filter shown in FIG. 10 is used in an enclosed space such as an automobile, the control frequency of the adaptive notch filter 1b is constant from the gain peak frequency. , Ie, f _control = f _peak ± α [Hz] (α is an arbitrary positive number, f _peak : gain peak frequency, f _control : control frequency of the adaptive notch filter 1b) However, there is a problem in that the cancellation sound output from the speaker is superposed on the gain peak frequency component of music received in a closed space such as an automobile, resulting in a significant increase in sound, which adversely affects audio quality. Was.

  The present invention solves the above-mentioned conventional problems, and can reduce an increase in sound due to a cancellation sound output from a speaker with respect to a gain peak frequency component of music received in a sealed space. Provided is an active vibration noise reduction device that can surely suppress adverse effects on sound quality.

In order to solve the above problems, the present invention has the following configuration.
According to a first aspect of the present invention, there is provided an active vibration noise reduction apparatus including a one-tap adaptive notch filter that outputs a noise cancellation signal for canceling vibration noise generated from a vibration noise source, and the noise cancellation signal. A control signal obtained on the basis of the vibration noise canceling means for canceling the vibration noise by canceling the vibration noise, and detecting and outputting an error signal due to interference between the vibration noise and the cancellation sound An active vibration noise reduction device having an error signal detection means that has a predetermined notch filter frequency corresponding to an acoustic transfer characteristic between the vibration noise cancellation means detected as the error signal and the error signal detection means. Notch filter reference cosine wave signal and notch filter reference signal generation means for outputting a notch filter reference cosine wave signal, and the notch filter reference cosine wave signal A first notch filter that outputs a first notch filter signal reflecting the first notch filter coefficient, and a second notch filter signal that reflects a second notch filter coefficient with respect to the notch filter reference sine wave signal. A second notch filter to be output, a coefficient update signal obtained by adding a notch filter addition signal obtained by adding the first notch filter signal and the second notch filter signal, and the noise cancellation signal, and the notch filter First notch filter coefficient updating means for updating the first notch filter coefficient based on a reference cosine wave signal, and updating the second notch filter coefficient based on the coefficient update signal and the notch filter reference sine wave signal. Second notch filter coefficient updating means for reflecting the updated first notch filter coefficient Output a signal obtained by multiplying a notch filter addition signal obtained by adding the first notch filter signal and the second notch filter signal reflecting the updated second notch filter coefficient by a predetermined attenuation parameter. Another one-tap notch filter having an attenuating means for adding the signal output from the attenuating means and the noise canceling signal and outputting the sum as a control signal. The vibration noise canceling means is configured to cancel and cancel the vibration noise by the canceling sound output according to the control signal.

  The active vibration noise reduction device according to claim 2 of the present invention is the active vibration noise reduction device according to claim 1, wherein the predetermined notch filter frequency is a reference of the one-tap adaptive notch filter. It is based on the frequency of the signal.

  The active vibration noise reduction device according to claim 3 of the present invention is the active vibration noise reduction device according to claim 1, wherein the other one-tap notch filter is configured to reduce the noise cancellation signal. When the frequency is within a predetermined range, the notch filter reference signal generating means operates by being driven.

  The active vibration noise reduction device according to claim 4 of the present invention is the active vibration noise reduction device according to claim 1, wherein the other one-tap notch filter is connected to the error signal detection means. The notch filter reference signal generating means operates based on an output level of a predetermined frequency component of the error signal.

  As described above, according to the present invention, another one-tap notch filter is newly provided, and the output signal from the other one-tap notch filter is added to the noise cancellation signal output from the one-tap adaptive notch filter. By using the signal as a control signal, it is possible to arbitrarily suppress the output of frequency components in a predetermined range of the canceling sound.

  Therefore, when this active vibration noise reduction device is applied to the interior of the vehicle, it is possible to suppress the output of the canceling sound near the gain peak frequency. Thus, it is possible to reduce the sound increase due to the cancellation sound output from the speaker, and to reliably suppress the adverse effect on the sound quality of the audio.

Hereinafter, an embodiment of an active vibration noise reduction apparatus according to the present invention will be described in detail with reference to FIGS. In addition, the same part as a prior art attaches | subjects the same code | symbol, and abbreviate | omits description.
(Embodiment)
FIG. 1 is a block diagram showing the configuration of an active vibration noise reduction apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of another one-tap notch filter which is the main part. 3, FIG. 4 and FIG. 6 are frequency characteristics (1) explanatory diagram, (2) explanatory diagram and (3) explanatory diagram of another one-tap notch filter which is the main part, and FIG. FIG. 7 is a characteristic explanatory diagram and FIG. 7 is a frequency characteristic explanatory diagram comparing effects with a conventional active vibration noise reduction device in the same vehicle. FIG. 8 is a configuration of another one-tap notch filter which is a main part of the same development example. FIG. 9 is a block diagram showing the configuration of another one-tap notch filter, which is the main part of another development example, and reduces the humming noise that is synchronized with the engine rotation, which is the main noise in the passenger compartment. An example of this will be described.

  As shown in FIG. 1, the active vibration noise reduction device of the present embodiment includes a SAN type 1-tap adaptive notch filter (tap adaptive notch filter) 1 and another 1-tap type notch filter provided at the output portion thereof. 2, a speaker 3 serving as vibration noise canceling means, and a microphone 4 serving as error signal detecting means. The SAN type one-tap adaptive notch filter 1 and the other one-tap notch filter 2 are sequentially processed. This is performed by the microcomputer 5.

  Since the difference from the prior art is another one-tap notch filter 2, the entire description is omitted here, and only the part related to the other one-tap notch filter 2, which is the difference, will be described.

  As shown in FIG. 2, the other one-tap notch filter 2 has an acoustic transfer characteristic between the speaker 3 as the vibration noise canceling means detected as the error signal and the microphone 4 as the error signal detecting means. A notch filter reference signal generating means 2c for outputting a notch filter reference cosine wave signal 2a and a notch filter reference sine wave signal 2b having a predetermined notch filter frequency, a first notch filter 2d, a second notch filter 2e, and a first notch. The filter coefficient update means 2f, the second notch filter coefficient update means 2g, the attenuation means 2h, and a plurality of adders 10a, 10b, and 10c.

The operation of the other one-tap notch filter 2 will be described below.
The notch filter reference cosine wave signal 2a and the notch filter reference sine wave signal 2b are output by the notch filter reference signal generation means 2c.

  The product of the coefficients of the notch filter reference cosine wave signal 2a and the first notch filter 2d and the product of the coefficients of the notch filter reference sine wave signal 2b and the second notch filter 2e are added by the adder 10a to obtain a notch filter addition signal Vout_s. Is output.

  The notch filter addition signal Vout_s and the noise cancellation signal Vin from the SAN type 1-tap adaptive notch filter 1 are added by the adder 10b, and the first notch filter coefficient update means 2f and the second notch filter coefficient update means are used as the coefficient update signal Vin_s. 2g is output.

  The first notch filter coefficient updating means 2f updates the coefficient of the first notch filter 2d based on the coefficient update signal Vin_s and the notch filter reference cosine wave signal 2a so that the coefficient update signal Vin_s is minimized by the least square method. Similarly, the second notch filter coefficient updating means 2g determines the coefficient 2e of the second notch filter based on the coefficient update signal Vin_s and the notch filter reference sine wave signal 2b so that the coefficient update signal Vin_s is minimized by the least square method. Update.

Next, the case where the coefficient update formulas of the first notch filter 2d and the second notch filter 2e are obtained will be described.
Assuming that the coefficient of the first notch filter 2d is w1, the update equation of the first notch filter 2d is expressed by equation (1) from the least square method.

なお、ｎはマイクロコンピュータ５の逐次演算のステップ数であり、μ＿ｆｉｘは最小二乗法の逐次演算のステップサイズパラメータである。

Note that n is the number of steps of sequential calculation of the microcomputer 5, and μ_fix is a step size parameter of sequential calculation of the least square method.

  here

より、式（１）は下記の式（３）となる。

Therefore, the formula (1) becomes the following formula (3).

ω_０は、他の１タップ型ノッチフィルタ２が持つ所定の角周波数である。

ω ₀ is a predetermined angular frequency that the other one-tap notch filter 2 has.

  Similarly, when the coefficient of the second notch filter 2e is set to w2, the coefficient update formula of the second notch filter 2e is the following formula (4).

ここで、Ｖｏｕｔ＿ｓは第１ノッチフィルタ２ｄからの信号と第２ノッチフィルタ２ｅからの信号の加算信号なので、

Here, Vout_s is an addition signal of the signal from the first notch filter 2d and the signal from the second notch filter 2e.

とした。

It was.

The frequency characteristic of Vout_s / Vin_s by this filter operation is as shown in FIG. 3 (FIG. 3 shows the case where ω ₀ = 2π × 50 [rad / sec] and μ_fix = 0.04).

  Further, the product of the notch filter addition signal Vout_s and the predetermined attenuation parameter Red_fe output by this calculation process and the noise canceling signal Vin are added by the adder 10c,

の制御信号Ｖｏｕｔがスピーカ３に入力される。

The control signal Vout is input to the speaker 3.

  At this time, the attenuation (Vout / Vin) at the notch filter frequency is expressed by the following equation (7).

また、この演算によるＶｏｕｔ／Ｖｉｎの周波数特性（他の１タップ型ノッチフィルタ２の周波数特性）は、図４（図４はω_０＝２π×５０［ｒａｄ／ｓｅｃ］、μ＿ｆｉｘ＝０．０４とした場合を示す）のような特性となる。

The frequency characteristics of Vout / Vin (frequency characteristics of other one-tap notch filters 2) obtained by this calculation are as shown in FIG. 4 (FIG. 4 is ω ₀ = 2π × 50 [rad / sec], μ_fix = 0.04). The characteristics are as shown in FIG.

  The acoustic transfer characteristic including the speaker 3 to the microphone 4 of the active vibration noise reduction device having the other one-tap notch filter 2 has a large gain peak suppressed and steep as shown in FIG. The phase rotation is gentle.

FIG. 5 shows the case where ω ₀ = 2π × 73 [rad / sec] and μ_fix = 0.16, and the frequency characteristics Vout / Vin of the other one-tap notch filter 2 are as shown in FIG. .

FIG. 7 is an explanatory diagram of frequency characteristics showing differences from the prior art. FIG. 7 shows a conventional active vibration noise reduction device and another one-tap notch filter 2 (ω ₀ = 2π × 73 [rad / sec], μ_fix = 0.16), and the active vibration noise reduction apparatus is showing that the music component in the vicinity of 70 Hz is being increased during 60 Hz control.

  In the case where the solid line is without an active vibration noise reduction device, the alternate line is the conventional active vibration noise reduction device, the dotted line is an active vibration noise reduction device having another one-tap notch filter 2 in the present embodiment. In this case, the relationship between the sound pressure level and the frequency indicates that the sound increase is clearly suppressed.

Hereinafter, a development example in which further features are provided in the notch filter reference signal generation means 2c of the other one-tap notch filter 2 in the active vibration noise reduction device of the present embodiment will be described.
(Development example 1)
The difference between this development example and this embodiment (FIG. 1) is that, in the other one-tap notch filter 2 of this embodiment, the noise cancellation signal Vin is generated as a notch filter reference signal as shown in FIG. a point obtained by those performed on the basis of the noise canceling signal Vin decisions notch filter frequency f ₀ of the notch filter reference signal generating means 2c by entering the unit 2c.

That is, since the frequency of the noise cancellation signal Vin is the frequency of the reference signal of the SAN type 1-tap notch filter 1, f ₀ = f _control ± β [Hz] (β is arbitrarily set according to the bandwidth of the frequency with a large gain. To generate a reference signal having a notch filter frequency.

Since the frequency of the noise cancellation signal Vin and the notch filter frequency have the relationship as described above, the notch filter frequency, that is, the frequency band for suppressing the sound increase is not constant, and the sound increase is suppressed following the control frequency. Since the frequency also changes, it is possible to always suppress the sound increase caused by the canceling sound, and it is possible to correspond to a space having various acoustic transfer characteristics.
(Development example 2)
Although the active vibration noise reduction device of the present development example is not particularly shown as a block diagram, in FIG. 8 illustrating the development example 1, when the noise cancellation signal Vin is input to the notch filter reference signal generating means 2c, the reference signal This is performed via the generation possibility determination means.

  That is, the notch filter reference signal generating means 2c of the other one-tap notch filter 2 is configured to determine whether or not to generate a reference signal based on the frequency band of the noise cancellation signal Vin.

For example, if the active vibration noise reduction device is applied to the space having the acoustic transfer characteristics shown in FIG. 3, the reference signal generation enable / disable determining means has a canceling sound at 60-80 Hz in the frequency band shown in FIG. When the frequency is not near the gain peak frequency, the music does not significantly increase due to the canceling sound. Therefore, the other one-tap notch filter 2 is not operated and the frequency of the noise canceling signal is 60 to 80 Hz. Only in the vicinity, the notch filter reference signal generation means 2c generates a reference signal and operates the other one-tap notch filter 2 so that the one-tap type has been performed in other frequency ranges. The amount of computation can be reduced by the amount of computation of the notch filter 2.
(Development example 3)
The difference between this development example and this embodiment is that the notch filter reference signal generating means 2c of the other one-tap notch filter 2 of this embodiment has an error output from the microphone 4 as shown in FIG. When a signal is input to the notch filter reference signal generation means 2c, it is configured to be input via the reference signal generation availability determination means 11.

  The reference signal generation availability determination unit 11 is configured to determine whether or not to generate a reference signal based on an output level of a predetermined frequency of the error signal output from the microphone 4.

  That is, when the active vibration noise reduction device of this example is applied to the space having the acoustic transfer characteristics shown in FIG. 11, there is no music frequency component near the gain peak frequency existing in 60-80 Hz, or human When the output level cannot be grasped by the auditory sense, when the output level of the component near the gain peak frequency of the music is increased by the canceling sound without operating the other one-tap notch filter 2 The notch filter reference signal generating means 2c generates the reference signal and operates the other one-tap notch filter 2 only when the sound increase is at a level that can be grasped by human hearing. The amount of computation can be reduced by the amount of computation performed by the other one-tap notch filter 2 that has been performed even when the output level is low. It is.

  As described above, the active vibration noise reduction device according to the present embodiment and the development example uses the other one-tap notch filter 2 to generate the gain peak frequency component of the acoustic transfer characteristic including the speaker output from the speaker to the microphone. By suppressing, it is possible to effectively suppress the increase of music components near the control frequency and other noise components.

  Therefore, even when an occupant is listening to music when boarding an automobile, the noise in the vehicle is muted and the effect of the gain peak frequency component of the acoustic transfer characteristics on the sound quality of the music component (music increase) is low. It is possible to provide a vibration noise reduction device.

  The active vibration noise reduction device of the present invention can reduce the increase in sound due to the cancellation sound output from the speaker with respect to the gain peak frequency component of the music received in the sealed space, thereby improving the sound quality of the audio. The adverse effect can be surely suppressed, and it can be used in the interior space of a mobile device such as an automobile, and further can be expected to be applied to residential spaces such as houses, condominiums, and offices.

The block diagram which shows the structure of the active vibration noise reduction apparatus of embodiment of this invention The block diagram which shows the structure of the other 1 tap type notch filter which is the principal part in the active vibration noise reduction apparatus of the embodiment Frequency characteristics (1) explanatory diagram of another one-tap notch filter which is a main part in the active vibration noise reduction device of the same embodiment Frequency characteristic (2) explanatory drawing of other 1 tap type notch filters which are the principal part in the active type vibration noise reduction device of the embodiment Explanatory drawing of frequency characteristics in the car when the active vibration noise reduction device of the embodiment is applied in the car Frequency characteristic (3) explanatory drawing of other 1 tap type notch filters which are the principal part in the active type vibration noise reduction device of the embodiment Frequency characteristics explanatory diagram for comparing the effect in the vehicle with the conventional example of the active vibration noise reduction device of the embodiment The block diagram which shows the structure of the other 1 tap type notch filter which is the principal part in the example of expansion | deployment of the active vibration noise reduction apparatus of the embodiment The block diagram which shows the structure of the other 1 tap type notch filter which is the principal part in the other expansion example of the active vibration noise reduction apparatus of the embodiment. Block diagram showing the configuration of a conventional active vibration noise reduction device Illustration of acoustic transmission frequency characteristics in a typical automobile

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 SAN type 1-tap adaptive notch filter 1a Reference signal generation means 1aa Cosine wave generator 1ab Sine wave generator 1ac Control frequency calculation means 1b Adaptive notch filter 1ba First adaptive notch filter 1bb Second adaptive notch filter 1c Simulation signal generation means 1ca Simulated cosine wave signal generating means 1cb Simulated sine wave signal generating means 1d Filter coefficient updating means 1da First coefficient updating means 1db Second coefficient updating means 2 Other one tap type notch filter 2a Notch filter reference cosine wave signal 2b Notch filter reference sine Wave signal 2c Notch filter reference signal generating means 2d First notch filter 2e Second notch filter 2f First notch filter coefficient updating means 2g Second notch filter coefficient updating means 2h Attenuating means 3 Speaker 4 Microphone 10, 10a, 1 b, 10c adder 11 reference signal generating permission determining means

Claims (4)

A one-tap adaptive notch filter that outputs a noise cancellation signal to cancel vibration noise generated from a vibration noise source;
Vibration noise canceling means for inputting a control signal obtained based on the noise canceling signal and outputting a canceling sound that cancels and cancels the vibration noise;
In an active vibration noise reduction device having error signal detection means for detecting and outputting an error signal due to interference between the vibration noise and the canceling sound,
A notch filter reference cosine wave signal and a notch filter reference sine wave signal having a predetermined notch filter frequency corresponding to acoustic transfer characteristics between the vibration noise canceling means and the error signal detection means detected as the error signal are output. Notch filter reference signal generating means;
A first notch filter that outputs a first notch filter signal reflecting a first notch filter coefficient with respect to the notch filter reference cosine wave signal;
A second notch filter that outputs a second notch filter signal reflecting a second notch filter coefficient with respect to the notch filter reference sine wave signal;
Based on a coefficient update signal obtained by adding the notch filter addition signal obtained by adding the first notch filter signal and the second notch filter signal and the noise cancellation signal and the notch filter reference cosine wave signal, First notch filter coefficient updating means for updating the first notch filter coefficient;
Second notch filter coefficient updating means for updating the second notch filter coefficient based on the coefficient update signal and the notch filter reference sine wave signal;
A notch filter addition signal obtained by adding the first notch filter signal reflecting the updated first notch filter coefficient and the second notch filter signal reflecting the updated second notch filter coefficient. On the other hand, another one-tap notch filter having attenuation means for outputting a signal multiplied by a predetermined attenuation parameter is provided,
The other one-tap notch filter is
Add the signal output from the attenuation means and the noise cancellation signal and output as the control signal,
The vibration noise canceling means is
An active vibration noise reducing apparatus configured to cancel and cancel the vibration noise by the canceling sound output according to the control signal. 2. The active vibration noise reduction device according to claim 1, wherein the predetermined notch filter frequency is based on a frequency of a reference signal of the one-tap adaptive notch filter. The other one-tap notch filter is
When the frequency of the noise cancellation signal is within a predetermined range,
2. The active vibration noise reduction apparatus according to claim 1, wherein the notch filter reference signal generation means operates when driven. The other one-tap notch filter is
Based on the output level of a predetermined frequency component of the error signal from the error signal detection means,
2. The active vibration noise reduction apparatus according to claim 1, wherein the notch filter reference signal generation means operates when driven.

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