JPS59230315A - Correcting device for characteristic of sound field frequency - Google Patents

Abstract

PURPOSE:To obtain the flat sound field frequency characteristics at any listening position in a short time and in an easy and automatic way, by using a microcomputer to control an electronic graphic equalizer. CONSTITUTION:The pink noise produced at a pink noise generating part 17 is delivered through a speaker 26 after passing through an electronic graphic equalizer 19 and an amplifier 27. This delivered noise is collected by a mike 25 and undergoes the band division every 1/3 octaves by a BPF20 through a mike amplifier 19 to be digitized by an A/D converter 21. This digital noise is fetched to a microcomputer 22, and the computer 22 controls the equalizer 19 in order to obtain the flat characteristics of frequency by an automatic correction program for sound field frequency characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sound field frequency characteristic correction device that can easily obtain a flat sound field frequency characteristic at the listening position when listening to music using a stereo device in a listening room. It is something.

A conventional sound field frequency characteristic correction device will be described below.

FIG. 1 shows a block diagram of a conventional sound field frequency characteristic correction device, in which 1 is a microphone, 2 is an audio frequency analyzer, 3 is a microphone amplifier, 4 is a frequency selection switch, and 5 is a block diagram of a conventional sound field frequency characteristic correction device.
is a level meter, 6 is a pink noise generator, 7 is an amplifier, and 8 is a graphic equalizer consisting of a volume that allows the level of each divided frequency to be manually varied.
9 is a speaker.

The operation of the conventional sound field frequency characteristic correction device configured as described above in more than three pages will be described below.

First, the pink noise generated by the pink noise generator 6 in the audio frequency analyzer 2 and radiated from the speaker 9 via the amplifier 7 is connected to the audio frequency analyzer 2.
Then, pick up the sound with a microphone installed at the listening position, change the frequency from 20) (z to 20i) in % octave units using the frequency selection switch 4, read the sound pressure level for each frequency with the level meter 5, and set the frequency. Fill in the sound pressure level characteristic recording sheet.After filling in all frequency bands, find out the frequencies that correspond to the maximum peak and maximum dip, and try to approach the average level of the maximum peak and maximum dip. Manually vary the level of the graphic equalizer 8.The above operation is performed within the specified range (usually 2
Repeat until it reaches ~3dB).

However, with the above configuration, it is necessary to read the level for each frequency one by one, and it is necessary to manually change the level of the graphic equalizer 8 to correct for distortion. There are problems such as not being able to immediately determine the effect of the signal on the level of nearby frequencies, and the lower the center frequency, the narrower the bandwidth, the greater the randomness, and the need to average the measured values. The difference between the maximum peak and maximum dip is 2 to 3 d.
There is a problem in that it usually takes several hours to keep the temperature within the range of B.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a sound field frequency characteristic correction device that can easily and automatically obtain flat sound field frequency characteristics at any listening position in any listening room in a short time. The purpose is to provide.

Structure of the Invention The present invention uses a microphone to pick up pink noise generated in a pink noise generation section in a sound field frequency characteristic correction device and emitted from a speaker via an amplifier, and converts the collected signal into a band. A/D after band division with pass filter
A sound field measurement means for converting the sound field spectrum level and importing it into a microcomputer as a sound field spectrum level, a storage means for storing the taken-in sound field spectrum level, and a sound field measurement means for storing the sound field spectrum level stored in the storage means in a specified frequency band. sound field correction means for controlling the electronic graphic equalizer so that the difference between the maximum peak and the maximum dip is equal to or less than a specified value; This is a sound field frequency characteristic correction device equipped with display means for displaying on a cathode ray tube, and is capable of easily and automatically obtaining flat sound field frequency characteristics at any listening position for any type of listening. be.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a block diagram of a sound field frequency characteristic correcting device in a first embodiment of the present invention.

In Figure 2 on page 6, 1o is a sound field measuring means that measures the pink noise generated in the pink noise generating part of this device and radiated from the speaker connected to the amplifier via the amplifier connected to this device. Sound is collected by a microphone connected to the device, divided into bands by a bandpass filter, and then A/D converted and captured as a sound field spectrum level. 11 is a storage means,
The sound field spectrum level captured by the sound field measuring means is stored. Reference numeral 12 denotes a sound field correction means that controls the electronic graphic equalizer so that the difference between the maximum peak and the maximum dip falls within the specified range in the frequency band of the specified range of the sound field spectrum level stored in the storage means. A display means 13 displays the sound field spectrum level stored in the storage means and the level of each frequency band of the electronic graphic equalizer on a CRT display.

FIG. 3 is a circuit block diagram showing a specific configuration of this embodiment. In FIG. 3, 14 is the sound field frequency characteristic correction device of the present invention, 14a is a signal input terminal, 14b is a signal output terminal, 14C is a microphone input page 7 terminal, 15 is a microphone amplifier, and 16 is a signal input terminal and a microphone input terminal. Input selector switch A11 to switch to either one
γ is the pink noise generation section, 18 is the pink noise generation section 1
The input selector switch B119 that switches between the output of the output and the output of the input selector switch A16 is 20Hz~
An electronic graphic equalizer consisting of an electronic volume that allows the level of each frequency, in which 20klb is divided into 31 channels in the Z octave, to be variable in 2dB increments within a range of ±12dB under the control of a microcomputer.
2o is a % octave band pass filter, 211d is an A/D converter, 22 is a microcomputer, which controls the A/D converter 21 and captures its output data; Transfers display data to the display control unit 23 and controls the electronic graphic equalizer 19.

22 & is a central processing control unit (hereinafter referred to as CPU), 2
2b is an input section, 22C is an output section, 22d is a storage section, 023 is a display control section, 24 is a CRT display, 25
is a microphone, 26 is a speaker, 27 is an amplifier for general audio, 27a is a recording output terminal, 2
7b is a reproduction input terminal, and 27c is a speaker terminal. 2
8 is an equalizer flat switch that sets all levels of the electronic graphic equalizer 19 to OdB; 29 is an automatic correction start switch that starts automatic correction of sound field frequency characteristics;
30 is a memory switch for storing the level position of the electronic graphic equalizer 19, and is composed of a memory button and memory number buttons 1 to 4. 31 is a channel changeover switch for the left channel and right channel.

The operation of the sound field frequency correction device of this embodiment configured as described above will be described below.

First, the speaker 26 is installed at the position where music is normally listened to in the listening room, and the microphone 25 is installed at the listening position. Set the input switch A16 to the microphone amplifier 15 side, and set the input switch B18 to the pink noise generator 17 side.
2. Switch the channel changeover switch 31 to the left channel side, press the equalizer flat switch 28 on page 9, and set all levels of the electronic graphic equalizer 19 to OdB. Next, by pressing the automatic correction start switch 29, the sound field frequency characteristic automatic correction is started, and the pink noise generated in the pink noise generation section 17 is removed by the electronic graphic equalizer 1.
9, is output from the signal output terminal 14b of the device 14, inputted to the reproduction input terminal 27b of the amplifier 27, and radiated from the speaker 26 connected to the speaker terminal 27C of the amplifier 27. The emitted pink noise is collected by a microphone 26, passed through a microphone amplifier 19, divided into bands in % octave units by a bandpass filter 20, digitized by an A/D converter 21, and then sent to a microcomputer 22.
The electronic graphic equalizer 19 is controlled so as to obtain a frequency flat characteristic by a sound field frequency characteristic automatic correction program. Figures 4 to 6 are 70 charts of the sound field frequency characteristic automatic correction program, and Figure 7 is CR.
This is an example of a screen display on a T display.

With reference to FIG. 4, the sound field frequency characteristic automatic correction progera 1o pagem will be explained. First, by pressing the automatic correction start switch 29 in FIG. 3, "AUTO5TART" is displayed on the CRT display screen, and a series of processes such as sound field measurement and equalizer control for sound field correction are performed. Set the upper limit number of times (temporarily assumed to be ENO) and the number of measurement sampling times (temporarily assumed to be SNO), which is the average of how many sound field measurements should be taken as one sound field measurement value. In this example, both cases are repeated 16 times. Next, a counter for checking the upper limit number of times of equalizer control processing is set to 0 and initialized. Next, add 1 to the counter ■, measure the sound field, obtain the spectrum level of 31 channels plus all bands ■, and compare those spectrum levels to the seventh
■Display as a bar graph as shown in the figure.

Next, find the maximum peak (temporarily set as P), maximum dip (temporarily set as D), and difference between the maximum peak and maximum dip (temporarily set as DT), and determine whether DT is 2 dB or less.■, if YES. It is assumed that the sound field frequency has been flattened, and "AUTO11 PAGE END" is displayed on the screen, and the process ends. If NO, DT is 3
dB, and if it is No, the flag for distinguishing the equalizer control method is set to 0, and the equalizer control process [phase] and the following are performed. If YES, find the number of frequencies that have the maximum peak (temporarily let it be N1) and determine whether N1 is 16 or more; if YES, find the maximum peak that has the majority of the maximum peaks and the level is exactly the same. For frequencies with a maximum dip, the level variable control of the equalizer is not performed, and the equalizer control is performed only for the maximum dip.
2) and determine whether N2 is 16 or more and 0
, if YES, set the flag to 1 [phase]; if No, set the flag to 0 0° Reduce the equalizer level of the frequency with the maximum peak by DT/2 dB [phase]
, determine whether the new decreased level is less than 112 dB @
Only when 1 is YES, the new level is set to -12 dB [phase].

Determine whether the flag is 1 or not. If YES, control the equalizer and process the screen display. If NO, increase the equalizer level of the frequency with the maximum dip by DT/2 and set the new level to 0. Determine whether it is greater than +12dB @, only if YES, set the new level to +12d
Let it be B. Next, control the equalizer so that it becomes the new level, and rewrite the equalizer part of the screen display to the new level.0゜Finally, determine whether the counter is equal to or greater than the equalizer control number (ENO) set at the beginning. If YES, return to the process of incrementing the counter by 1 and display 'AUTOEND' on the screen. 00 As mentioned above, in this program, in addition to the condition of 2 dB which is considered to be a flat sound field frequency, the upper limit of the number of times of equalizer control is set. did.

Next, the sound field measurement program (■ in FIG. 4) will be explained with reference to FIG. First, the spectrum level data of 31 channels plus all bands is taken from the output of the A/D converter.
1 Repeat the process 0 of adding the level to each channel by the number of measurement sampling times (SNO) ■. Next, divide the level added to page 13 for each channel by SNO to find the average level, which is 0.
Return to the sound field frequency characteristic automatic correction program in FIG. 4.

Next, the spectrum display program (■ in FIG. 4) will be explained with reference to FIG. First, read the spectrum level of each channel into the register■, judge whether the level is greater than +10dB, and if YES, set the level to +
10dB ■, N.

If so, next time determine whether the level is less than 13 odB [Yes], and if YES, set the level to -30 dB■, N
If it is o, the level remains as it was imported. Next, determine whether the level is equal to the previous level. If YES, there is no need to control the screen display and move on to processing the next channel; if NO, determine whether the level is less than the previous level. If the judgment is @, YES, or S, the dot in the bar graph of the corresponding channel of the spectrum on the screen will be erased, and if it is No, the dot will be displayed. Finally, save the spectrum level data to the previous level data area. The process returns to the sound field frequency characteristic automatic correction program shown in FIG. 4, which repeats the above-described series of processes @ to pages 14 for 31 channels.

Figure 7 shows that the CRT display 2 is
4 shows an actual display example displayed on the screen. 7th
In the figure, numeral 32 represents the spectrum level in the form of a bar graph, and numeral 33 represents the numeric value representing the spectrum level, which in this embodiment is set to -30 to +10 dB. 34 is a frequency divided from 20% to 20% in % octave units, and ALL represents the total level of the entire band. 35 represents the level of the equalizer, which in this example ranges from -12 dB to +12 dB.
dB, and the scale is in 2 dB increments. Reference numeral 36 represents the level position of the equalizer for each frequency, 37 represents the current channel (L/R), and 38 represents the start and end of automatic correction.

Note that the sound field corrected level of the electronic graphic equalizer 19 can be stored in the storage section 22d by operating the memory switch 3o.

After automatic correction as described above, this device 1 in FIG.
4 input changeover switch A16 to the signal input 15 page terminal 14a side, input changeover switch B18 to the input changeover switch A16 side, and the amplifier 27 is set to FM/
An AM tuner, record player, tape deck, etc. is connected, and their music signals are sent to the recording output terminal 2 of the amplifier 27.
Completion a → Signal input terminal 14a → Input selector switch A16 →
By passing through the input changeover switch B18→electronic graphic equalizer 19→signal output terminal 14b→playback input terminal 27b, music can be enjoyed with the sound field corrected.

As described above, according to this implementation, by using this device, no matter what listening position you are in the listening room, you can easily obtain a flat sound field frequency characteristic at that location. This can be achieved in a very short period of time, only a few seconds after the automatic correction start switch 29 is pressed.

In addition, by installing a CRT display and displaying the spectrum and equalizer, you can see the frequency analysis results of the sound field at a glance, and easily observe the movement of the equalizer level due to the automatic correction of the sound field frequency characteristics and the frequency analysis results at that time. can do.

Effects of the Invention The present invention collects the pink noise generated in the pink noise generator and radiates from the speaker via the amplifier with a microphone, divides the band of the collected signal with a bandpass filter, and then performs A/D conversion. a sound field measuring means for capturing the sound field spectrum level into a microcomputer as a sound field spectrum level; a storage means for storing the captured sound field spectrum level; and a maximum peak of the sound field spectrum stored in the storage means in a specified range of frequency bands. sound field correction means for controlling the electronic graphic equalizer so that the difference in maximum dips is equal to or less than a specified value; and displaying the sound field spectrum stored in the storage means and the level of each frequency band of the electronic graphic equalizer on a CRT display. By providing a display means for displaying, flat sound field frequency characteristics at any listening position in any listening room can be easily and automatically obtained17.
In addition, the KCRTCRT display tract and equalizer display allow you to see the frequency analysis results of the sound field at a glance, and easily observe the movement of the equalizer level and the frequency analysis results at that time due to the automatic correction of the sound field frequency characteristics. It is possible to realize an excellent sound field frequency characteristic correction amount that can obtain the effect that it is possible.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional sound field frequency characteristic correction device.
Fig. 2 is a block diagram of a sound field frequency characteristic correction device according to an embodiment of the present invention, Fig. 3 is a block diagram showing a specific configuration of an embodiment of the present invention, and Fig. 4 is a block diagram of a sound field frequency characteristic correction device according to an embodiment of the present invention. 5 is a flowchart of the sound field measurement program, FIG. 6 is a flowchart of the spectrum display program, and FIG. 7 is an example of a CRT display screen display. 1...Microphone, 2...Audio frequency analyzer, 3...Mic amplifier, 4...
・Frequency selector switch, 6...Level meter,
6...Pink noise generator, 18 pages 7...Amplifier, 8...Manual graphic equalizer, 9...Speaker, 1o...
...Sound field measuring means, 11...Storage means, 12
...Sound field correction means, 14...Sound field frequency characteristic correction device, 14a...Signal input terminal, 1
4b... Signal output terminal, 14c... Microphone input terminal, 16... Microphone amplifier, 16.
・Input selector switch A117...Pink noise generating section, 18...Input selector switch B11
9...Electronic graphic equalizer, 2o...
...Band pass filter, 21...A/
D converter, 22...Microcomputer, 2
2a・CPU, 22b...Input section, 22c...Output section, 22d...Storage section, 23...Display control section, 24・・・・・・C
RT display, 26...Microphone, 26. Old...Speaker, 27...Amplifier, 2.
...Recording output terminal, 27b...Playback input terminal, 27c...Speaker terminal, 28...
Equalizer flat switch, 29... Automatic correction start switch, 30... Memory switch, 3
1...Channel selection switch, 32...
...Spectrum level bar graph, 33...
・Spectrum page 19 Numerical value representing level, 34... Frequency, 35.
...Numeric value representing the level of the equalizer, 36...
... Equalizer level position, 37 ... Current channel (L/R), 38 ... Display indicating start and end of automatic correction. Name of agent Patent attorney Toshio Nakao et al. 74- Figure 5 Figure 6

Claims (1)

[Claims] Pink noise generated in a pink noise generating section and emitted from a speaker via an amplifier is picked up by a microphone, and the picked up signal is band-divided by a bandpass filter and then subjected to analog/digital conversion. → Sound field measuring means for importing the sound field spectrum level into the microcomputer as the °C sound field spectrum level, storage means for storing the imported sound field spectrum level, and the maximum peak of the sound field spectrum stored in the storage means in a specified range of frequency bands. sound field correction means for controlling an electronic graphic equalizer by a program of the microcomputer, in which the level of each divided frequency is varied by the control of the microcomputer so that the difference between A sound field frequency characteristic correction device characterized by comprising display means for displaying the sound field spectrum stored in the storage means and the level of each two-page wave number band of the electronic graphic equalizer on a cathode ray tube.