JPH0754998B2 - Automatic sound field correction device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic sound field correction apparatus that automatically corrects frequency characteristics of a listening space to desired characteristics.

BACKGROUND ART FIG. 1 shows a conventional example of an automatic automatic sound field correction apparatus. In this apparatus, an audio signal output from a signal source 1 such as a tape deck is supplied to the adder 2. A test signal generator 3 is connected to the adder 2, and the test signal generator 3 generates a test signal having a clear characteristic such as pink noise. A graphic equalizer 4 having a plurality of adjustment bands is connected to the output end of the adder 2, and the output end of the graphic equalizer 4 constitutes the output end of this device. The power amplifier 5 of the sound reproducing device is connected to the output terminal thereof, and the speaker 6 is driven by the power amplifier 5.

The radiated sound of the speaker 6 is detected by the microphone 7, and the frequency characteristic detection circuit 8 is provided at the output end of the microphone 7.
Are connected. The frequency characteristic detection circuit 8 has a plurality of BPFs having mutually different characteristics and detects the frequency characteristic of the sound field according to the output signal of the microphone 7. A control circuit 10 is connected to the frequency characteristic detection circuit 8 via an A / D converter 9. The control circuit 10 preferably comprises a microcomputer and controls the operation of the test signal generator 3 and the gain level of each adjustment band of the graphic equalizer 4.

In such a configuration, the control circuit 10 activates the test signal generator 3 in response to an automatic sound field correction command from a keyboard (not shown). Therefore, the test signal is supplied to the graphic equalizer 4 via the adder 2. At this time, the supply of the audio signal from the signal source 1 to the adder 2 is stopped, and the frequency characteristic of the graphic equalizer 4 is set to a completely flat state by setting the gain level of each adjustment band to the same level. Graphic equalizer 4
The test signal output from the power amplifier 5 is amplified by the power amplifier 5 and supplied to the speaker 6, and the test signal reproduction sound is emitted from the speaker 6 to the listening space. At the listening point, the microphone 7 detects the sound pressure of the test signal reproduction sound,
The detected sound pressure signal is supplied to the frequency characteristic detection circuit 8. The frequency characteristic detection circuit 8 detects the sound pressure signal level corresponding to each adjustment band of the graphic equalizer 4, and each detection level is converted into digital data by the A / D converter 9 and supplied to the control circuit 10. . The control circuit 10 determines the frequency characteristic of the sound pressure signal detected in accordance with the digital data, that is, the frequency characteristic of the sound field, and adjusts the frequency characteristics of the sound field so that the frequency characteristic of the sound field becomes flat. The automatic sound field correction operation ends by controlling the gain level and deactivating the test signal generator 3.

By the way, normally, when a human hears an audio reproduction sound in a listening space, it is naturally affected by a head, a face, an auricle and the like, and nevertheless, especially in a listening space, a signal source, a power amplifier, a speaker, etc. If there is no element that disturbs the frequency characteristic of, it is determined that the frequency characteristic of the sound field is flat in hearing. Also, it is clear that it is better to correct the sound field in a practical state where human beings listen. Therefore, as shown in FIG. 2, the microphones 7 are arranged at the entrances of the ear canals of both ears to perform the same automatic sound field correction as above in an ideal listening space. Due to the influence, the frequency characteristic of the sound field obtained from the output signal of the frequency characteristic detecting circuit 8 becomes a characteristic different from that of the case of a single microphone, and is disturbed particularly in a high range as shown by a solid line a in FIG. The characteristics are not flat. If the graphic equalizer 4 is adjusted so as to have an inverse characteristic to this frequency characteristic, the frequency characteristic of the sound field becomes theoretically flat during audio reproduction. However, there is a problem that it is unnatural in terms of hearing.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic sound field correction device capable of correcting the frequency characteristic of a sound field so as to give a natural listening feeling when a microphone is provided in both ears of a listener.

The automatic sound field correction apparatus of the present invention is provided on either the supply line of the test signal to the electro-acoustic conversion means such as a speaker or the processing line of the output signals of the two microphones, so that the frequency characteristics of the sound field can be heard. It is characterized in that it comprises a compensation means for adjusting the level of a signal supplied for compensating the deviation with a predetermined non-flat frequency characteristic.

Example An example of the present invention will be described below with reference to FIG.

In the automatic sound field correcting apparatus according to one embodiment of the present invention shown in FIG. 4, the same parts as those of the apparatus shown in FIG. 1 are designated by the same reference numerals, and the output end of the frequency characteristic detecting circuit 8 is compensated. Circuit 11 is connected. The compensating circuit 11 is an amplifier or attenuator having a characteristic opposite to the frequency characteristic of the sound field obtained from the output signal of the frequency characteristic detecting circuit 8 in advance in an ideal listening space (for example, the characteristic shown by the broken line b in FIG. 3). The output signal of the compensation circuit 11 is supplied to the A / D converter 9. Further, the two microphones 7 are provided in both ears of the listener as shown in FIG.

The rest of the configuration of the automatic sound field correction device according to the present invention is the same as that of the device shown in FIG. 1, and therefore its explanation is omitted here.

In such a configuration, the output level of the frequency characteristic detection circuit 8 is compensated by the compensation circuit 11, and so-called weighting is performed. Therefore, the frequency characteristic detection circuit 8
Since the influence of the listener's head, face, auricle, etc. contained in the output signal of N.sub.2 is canceled and supplied to the control circuit 10 via the A / D converter 9, the sound field at the time of audio reproduction is actually The gain level of each adjustment band of the graphic equalizer 4 is not controlled so that the frequency characteristic of is flat, but is controlled so as to have a disturbance characteristic only by the deviation of the sense of hearing, that is, by the compensation by the compensation circuit 11.

In the above-described embodiment of the present invention, when the frequency characteristic detection circuit 8 has a plurality of BPFs having different characteristics and selectively uses the BPFs, the output of each BPF is set to the center frequency thereof. An attenuator having a corresponding amount of compensation may be added as a compensation means. When a wobble tone is used as the test signal sound, the compensation circuit 11 compensates each time by a compensation amount corresponding to the frequency of the wobble tone. In this case, it is also possible to use a plurality of attenuators or amplifiers having different compensation amounts and switch the attenuators or amplifiers according to the frequency of the wobble tone.

Further, in the above-described embodiment of the present invention, the compensating circuit 11 is provided between the frequency characteristic detecting circuit 8 and the A / D converter 9, but the compensating circuit 11 is not limited to this, and as shown in FIG. Even if the compensating circuit 12 is provided between the signal generator 3 and the adder 2, the same effect can be obtained.

EFFECTS OF THE INVENTION As described above, according to the automatic sound field correction apparatus of the present invention, the level of the signal supplied for compensating the auditory deviation of the frequency characteristic of the sound field is adjusted with a predetermined non-flat frequency characteristic. Since the compensating means is provided on either the supply line of the test signal to the electroacoustic converting means or the processing line of the output signals of the two microphones, the compensating means is provided on both ears.
By discriminating the frequency characteristic of the sound field from the output signals of the two microphones, the sound field can be corrected in a practical state, and the audio can be reproduced with the characteristic that is audible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional example of an automatic sound field correction device,
FIG. 2 is a diagram showing the arrangement of microphones, FIG. 3 is a diagram showing frequency characteristics of a sound field detected by the two microphones shown in FIG. 2 and its inverse characteristics, and FIG. 4 is an embodiment of the present invention. FIG. 5 is a block diagram showing an example, and FIG. 5 is a block diagram showing another embodiment of the present invention. Explanation of symbols of main parts 1 …… Signal source 3 …… Test signal generator 4 …… Graphic equalizer 5 …… Power amplifier 7 …… Microphone 8 …… Frequency characteristic detection circuit 10 …… Control circuit 11,12 …… Compensation circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Tokage 25-1 Nishimachi, Yamada, Kawagoe, Saitama Prefecture 1 Pioneer Corporation Kawagoe Factory (72) Inventor Toshikazu Yoshimi 1-25 Nishimachi, Yamada, Kawagoe, Saitama Pioneer Co., Ltd. Kawagoe Factory (56) Reference JP-A-53-120401 (JP, A) JP-A-50-141301 (JP, A)

Claims (2)

[Claims] 1. A graphic equalizer means provided on a supply line of an audio signal to an electroacoustic conversion means, and
Test signal generating means for generating a test signal so as to emit a test signal sound having a clear characteristic to the listening space by the electroacoustic converting means, and provided on both ears of a listener for detecting the emitted test signal sound. Frequency characteristics of the sound field based on the output signals of the two microphones and the frequency characteristics of the graphic equalizer means so that the frequency characteristics of the sound field become flat according to the result of the determination. Is provided on either the supply line of the test signal to the electroacoustic conversion means or the processing line of the output signal of the microphone in order to compensate the auditory deviation of the frequency characteristic of the sound field. And a compensating means for adjusting the level of the supplied signal with a predetermined non-flat frequency characteristic. 2. The automatic sound field correction apparatus according to claim 1, wherein the test signal sound is one of wobble tone, pink noise, and white noise.