JPH071960B2 - Sound field correction device and sound field correction method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field correction device and a correction method for automatically correcting a sound field in an audio device.

2. Description of the Related Art In recent years, an equalizer for correcting a sound field and a sound field correcting device that automatically measures a sound field by measuring a room acoustic characteristic have been widely used.

FIG. 4 shows the configuration of a conventional sound field correction device.
In FIG. 4, 1 is a signal generator for measurement, 2 is a fixed equalizer for sound field correction, 4 is an amplifier, 5 is a speaker, 6 is a microphone for acoustic characteristic measurement, and 7 is a signal from the microphone 6. Amplifier, 8 is a bandpass filter for dividing the amplified signal into each band, 9 is an acoustic characteristic measuring circuit for measuring the magnitude of the signal from the microphone 5, 10 is a correction value for the fixed equalizer 2 based on the measured value Reference numeral 11 denotes a correction characteristic calculation unit that controls the characteristics of the fixed equalizer 2.

The operation of the sound field correction device configured as described above will be described below. FIG. 5 is a flowchart showing a conventional sound field correction method.

The measurement signal from the measurement signal generator 1 passes through the fixed equalizer 2 having flat characteristics, is amplified by the amplifier 4, and is reproduced from the speaker 5. Next, the measurement signal is received by the microphone 6 placed at the listening position in the room and amplified by the amplifier 4 to an appropriate level. Next, the band pass filter 8 separates each band, and the acoustic characteristic measuring circuit 9 measures the sound pressure level of each band. Based on the value measured by the acoustic characteristic measuring circuit 9, the correction characteristic calculation unit 10 performs calculation so that the listening point characteristic becomes flat or a preset characteristic, and determines the correction characteristic of the fixed equalizer 2.
The determined correction value of the fixed equalizer 2 is transferred to the fixed equalizer 2 by the control unit 11, and the fixed equalizer 2
The correction characteristic is set.

By the above operation, it is possible to listen with a flat characteristic or a preset characteristic at the listening position.

Problems to be Solved by the Invention However, in the method as described above, the correction characteristic is calculated by one measurement, but since the fixed equalizer 2 is not an ideal bandpass filter, there is mutual interference between equalizers. There was an inconvenience that the field correction could not be performed well.

The present invention has been made in view of the above drawbacks, and an object of the present invention is to provide a sound field correction apparatus and a sound field correction method capable of improving the sound field correction accuracy.

Means for Solving Problems In order to solve the problems, the sound field correction device of the present invention is
Measurement signal generator for measuring the sound field in the room, acoustic measurement circuit for measuring acoustic characteristics, storage means for storing the measured values, and correction characteristic calculation for calculating the correction characteristics of the fixed and variable equalizers based on the measured acoustic characteristics Means, control means for setting the calculated correction value to fixed and variable equalizers, and fixed and variable equalizers, and using this fixed equalizer and variable equalizer, measurement → fixed equalizer correction → measurement → variable equalizer correction → measurement → As a method of performing a measurement each time the equalizer correction is completed in the order of fixed and variable equalizer correction, and another method, a frequency characteristic determined by the level, Q and center frequency of each equalizer is stored in the storage means. , The frequency characteristic of the equalizer corresponding to the calculated correction condition is read from the storage means and added to the measured value. It has become the way.

Effect The present invention measures the acoustic characteristics of the room by the above-described configuration, calculates and sets the correction value of the fixed equalizer, and also performs the measurement, calculates and sets the correction value of the variable equalizer, performs the measurement again, and fixes the fixed value. The final correction of the variable equalizer is performed, or the same process is performed to determine the correction values of the fixed and variable equalizers by using the frequency characteristics of each level and Q of the fixed and variable equalizer stored in the storage means. It is possible to improve the sound field correction accuracy by performing the correction in the first measurement without performing the measurement each time the correction is determined.

Embodiment A sound field correction apparatus according to an embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the conventional example shown in FIG. 4 are designated by the same reference numerals.

FIG. 1 shows the configuration of a sound field correction apparatus according to the first embodiment of the present invention. In FIG. 1, 1 is a measurement signal generator that generates a signal for acoustic characteristic measurement, 2 is a fixed equalizer whose input signal frequency is fixed, 3 is frequency, sharpness of resonance (hereinafter referred to as Q), and level are variable. Possible variable equalizer, 4 is an amplifier, 5 is a speaker, 6 is a microphone for measuring the acoustic characteristics of the room, 7 is an amplifier, 8 is a bandpass filter for dividing each band, 9 is a signal of each band from the bandpass filter 8. Acoustic characteristic measurement circuit to measure the size,
Reference numeral 12 denotes a microcomputer, which has a fixed equalizer 2 and a variable equalizer 3 based on the values measured by the acoustic characteristic measuring circuit 9.
And a controller 11 for setting the correction characteristic in the fixed equalizer 2 and the variable equalizer 3
It consists of and. A storage unit 13 stores the measurement value measured by the acoustic characteristic measuring circuit 9.

FIG. 2 shows a flowchart of the sound field correction method of the sound field correction apparatus of this embodiment.

The operation of the sound field correction method of the sound field correction device configured as described above will be described with reference to FIGS. 1 and 2.

First, the signal generated from the measurement signal generator 1 for measuring the acoustic characteristic of the room passes through the fixed equalizer 2 and the variable equalizer 3 which are set to the known characteristic in advance, passes through the amplifier 4, and is reproduced from the speaker 5. It Microphone 6
Then, any sound in the room is picked up, amplified by the amplifier 7 to an appropriate level, and then divided by the band pass filter 8 into each band. The acoustic characteristic measuring circuit 9 measures the sound pressure frequency characteristic, stores the value in the storage means 13, and then transfers it to the correction characteristic calculating means 10 (step 21).

The correction characteristic calculation means 10 obtains the average sound pressure level of the measured values, and then calculates the sound pressure level of each band of the fixed equalizer 2 to be the average sound pressure level (step 22), and the control means 11 performs the calculation. A correction value is set in the fixed equalizer (step 23).

The calculation method is shown in equation (1).

Calculation method of correction value of fixed equalizer L _F n ′ ＝ L _A1 −L _MF n …… (1) L _MF n: Sound pressure level L _A1 of the nth fixed equalizer L _A1 : First-time average sound pressure level L _F n ′: Correction level of the nth fixed equalizer Next, the measurement signal is generated again from the measurement signal generator 1,
The sound pressure frequency characteristic is measured by the same procedure as described above (step 24). The correction characteristic calculating means 10 again obtains the average sound pressure level of the measured values, selects several points of frequencies having a large difference from the average sound pressure level, and calculates the correction value (Q and level) (step 25). When there are frequency points with the same level difference, the low frequency points are preferentially selected. The calculation method is shown in equations (2) and (3).

Calculation method of correction value of variable equalizer Q calculation method Lfn: Sound pressure level in the nth correction frequency band Qfn: Q in the nth correction frequency band The obtained Q is converted into an actual Q using a conversion table.

Level calculation method Lfn ′ = L _A2 −Lfn (3) Lfn ′: Correction level of the n-th variable equalizer L _A2 : Second average sound pressure level The correction value obtained is sent to the variable equalizer 3 by the control means 11. It is set (step 26).

Next, the measurement signal is again generated from the measurement signal generator 1 and the sound pressure frequency characteristic is measured by the same procedure as described above (step 27). The correction characteristic calculating means 9 again calculates the average sound pressure level of the measured values, calculates the difference between the average sound pressure level of each frequency band of the fixed equalizer 2 and the variable equalizer 3 (step 28), and fixes it by the control means 11. The levels of the equalizer 2 and the variable equalizer 3 are set (step 29). The calculation method is shown in equations (4) and (5).

Calculation method of the correction value of the final fixed equalizer L _F n ″ ＝ L _A3 −L _MF n ＋ L _F n ′ (4) L _F n ″: Final correction level of the equalizer L _MF n: Fixed n th equalizer of the sound pressure level a _3: calculation Lfn correction value for the third time average sound pressure level last variable equalizers _{"= L A3 -L M fn +} Lfn '...... (5) Lfn": final correction of the n-th variable equalizer level L _M fn: According to a first embodiment of the n-th variable equalizer of the sound pressure level above the present invention, by performing the measurement for each perform fixing, the correction of the variable equalizer, improve the correction accuracy It is possible to

FIG. 3 shows a flowchart of the sound field correction method of the sound field correction apparatus according to the second embodiment of the present invention. The configuration of the sound field correction device is the same as in FIG.

The operation will be described below with reference to FIG.

First, as in the first embodiment, the sound pressure frequency characteristic is measured (step 31), the average sound pressure level is obtained by the correction characteristic calculating means 10, and then the sound pressure level of each frequency band of the fixed equalizer 2 is changed. A correction value is calculated so as to obtain the average sound pressure level (step 32).

The storage means 13 stores the frequency characteristic at each level of each band of the fixed equalizer 2 and the frequency characteristic at each Q, level, and center frequency of the variable equalizer 3. Even if the center frequencies are different, when the Q and level are the same, and when the characteristics of the band sandwiching the center frequencies are the same, it is not necessary to change the frequency characteristics for each center frequency, and the storage amount is reduced because it is relatively equal. Here, the frequency characteristic at the correction level of each frequency band is selected from the storage means 13 and added to the measured value (step 33).

Next, based on the sound pressure frequency characteristics newly obtained by the above calculation, the frequency points having a large difference from the average sound pressure level are selected, and the correction value (Q and level) is calculated (step 3).
Four). Storage means 1 for storing the frequency characteristic corresponding to the obtained correction value
Select from 3 and add to the sound pressure frequency characteristics (step 35).

Next, based on the sound pressure frequency characteristics obtained by the above calculation, the difference between the average sound pressure level of each frequency band of the fixed equalizer 2 and the variable equalizer 3 is calculated, and the already obtained fixed equalizer 2, It is added to the correction value of the variable equalizer 3 (step 36). The correction value obtained as described above is set in the fixed equalizer 2 and the variable equalizer 3 by the control means 10 (step 37).

As described above, according to the second embodiment of the present invention, the storage means
13, each level of fixed equalizer 2 and variable equalizer 3,
By storing the frequency characteristics at the Q and center frequencies and calculating the correction value for the fixed and variable equalizers using that value, it is possible to reduce the number of acoustic characteristic measurements without lowering the correction accuracy. The time spent on field correction can be shortened.

In the measurements of the first and second embodiments of the present invention, the number of averages is increased in the lower frequency band than in the higher frequency band to improve the measurement accuracy.

Further, in the Q value calculation method (2) of the first and second embodiments, the band to be corrected and the upper and lower two bands are used for the calculation, but the upper and lower several bands may be used for the calculation. .

EFFECTS OF THE INVENTION As described above, according to the present invention, the measurement and fixing of the room acoustic characteristics are performed stepwise, and the variable equalizer is corrected or fixed.
Each level of the variable equalizer, Q, the frequency characteristic for each center frequency is stored in the storage means, the correction value is calculated using the characteristic,
It is possible to improve the sound field correction accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of a sound field correction apparatus in the first and second embodiments of the present invention, FIG. 2 is a flow chart showing a sound field correction method of the first embodiment of the present invention, and FIG. Second invention
4 is a flowchart showing a sound field correction method of the embodiment, FIG. 4 is a block diagram of a conventional sound field correction apparatus, and FIG. 5 is a flowchart showing a conventional sound field correction method. 1 ... Measurement signal generator, 2 ... Fixed equalizer, 3 ...
Variable equalizer, 6 ... Microphone, 8 ... Band pass filter, 9 ... Acoustic characteristic measurement circuit, 10 ... Correction characteristic calculation section, 11 ... Control section, 12 ... Microcomputer,
13 ... Memory part.

Claims (5)

[Claims] 1. A measurement signal generator for generating a signal for measuring an acoustic characteristic in a room, a fixed equalizer and a variable equalizer for changing a frequency characteristic of the signal, and an acoustic measurement circuit for measuring the acoustic characteristic. Storage means for storing the measured value, correction characteristic calculation means for calculating correction characteristics of the fixed equalizer and the variable equalizer based on the measured value, and control means for determining the characteristics of the fixed equalizer and the variable equalizer A sound field correction device comprising: 2. A measurement signal generator for generating a signal for measuring an acoustic characteristic in a room, a fixed equalizer and a variable equalizer for changing a frequency characteristic of the signal, an acoustic physical property measuring circuit for measuring the acoustic characteristic, and a measurement. Storage means for storing the measured value, correction characteristic calculation means for calculating a correction characteristic of the fixed equalizer and the variable equalizer based on the measured value, control means for determining the characteristic of the fixed equalizer and the variable equalizer, Comprising, the fixed equalizer, a step of setting the variable equalizer to a known characteristic, generating a measurement signal from the measurement signal generator, to measure the characteristics of the signal generated by the acoustic characteristic measurement circuit,
Storing by the storage means, calculating a correction value for the level of the fixed equalizer by the correction characteristic calculation means based on the measured characteristics, and setting the correction value in the fixed equalizer by the control means And a step of generating a measurement signal, obtaining a characteristic of the signal generated by the acoustic characteristic measuring circuit, and storing the characteristic by the storage means, and the variable equalizer by the correction characteristic calculation means based on the measured characteristic. Of the frequency, level and resonance sharpness Q, calculating the correction value in the variable equalizer by the control means, generating a measurement signal from the measurement signal generator to generate the acoustic characteristic. Determining the characteristic of the signal generated by the measuring circuit and storing it in the storage means; Calculating a correction value for the level of the fixed equalizer and the variable equalizer by the acoustic characteristic measuring circuit based on the characteristic, and setting the correction value in the fixed equalizer and the variable equalizer by the control means. Sound field correction method for a sound field correction apparatus having the following. 3. The sound field correction method for a sound field correction device according to claim 2, wherein the number of times of averaging the acoustic characteristic measurement of the low frequency is increased as compared with the high frequency. 4. A measurement signal generator for generating a signal for measuring an acoustic characteristic in a room, a fixed equalizer and a variable equalizer for changing a frequency characteristic of the signal, an acoustic characteristic measuring circuit for measuring the acoustic characteristic, and a measurement. Storage means for storing the measured value, correction characteristic calculation means for calculating a correction characteristic of the fixed equalizer and the variable equalizer based on the measured value, control means for determining the characteristic of the fixed equalizer and the variable equalizer, A step of setting the fixed equalizer and the variable equalizer to known characteristics, generating a measurement signal from the measurement signal generator, and obtaining a characteristic of the signal generated by the acoustic characteristic measuring circuit, and storing the storage means. And a step of storing the level of the fixed equalizer by the correction characteristic calculation means based on the measured characteristic. A step of calculating a correction value; a step of reading the frequency characteristic of the correction value stored in the storage means; adding this to the stored frequency characteristic; and the variable equalizer based on the frequency characteristic obtained in the step. Calculating a correction value for the frequency, level, and sharpness Q of resonance, and reading the frequency characteristic previously stored in the storage means according to the correction value of the variable equalizer and adding it to the frequency characteristic.
The method further comprises the steps of recalculating the correction values of the levels of the fixed equalizer and the variable equalizer based on the frequency characteristic obtained in the above step, and the step of setting the correction value to the fixed equalizer and the variable equalizer by the control means. A sound field correction method for a sound field correction device. 5. The sound field correction method for a sound field correction device according to claim 4, wherein the number of times of averaging the acoustic characteristic measurement in the low frequency band is increased as compared with that in the high frequency band.