JPH06121396A - Listening position automatic correction device - Google Patents

Abstract

PURPOSE:To correct a deviation of a sound image by providing means detecting a rising of a test sound with the a test sound signal from a sound source as a reference and calculating and correcting a signal delay and level correction quantity based on a sound propagation time difference between plural speakers at symmetric positions and a listening position to the device. CONSTITUTION:Microphones 1, 2 provided at listening positions (both ears) of a driver's seat or an assistant's seat or the like asymmetrically situated in a car cabin 200 pick up a test sound reproduced by speakers 106, 107 and propagated in the cabin. A rising detection and time difference level calculation section 9 inputting the picked-up sound via amplifiers 3, 4 receives a test signal from a sound source 101 to make the calculation of the time difference and level difference. Time difference correction use delay sections 5, 6 and level difference. correction use attenuators 7, 8 correct the signal from the sound 101 based on the signal delay correction quantity and level correction quantity outputted by the calculation section 7 based on the result of calculation. Thus, the deviation in a sound image of the speakers 106, 107 at asymmetric positions is automatically corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio device mounted on a vehicle, and more particularly to correcting the bias of a sound image with respect to an asymmetrical arrangement of a plurality of speakers per listening position.

[0002]

2. Description of the Related Art Conventionally, there has been a listening position correction device as a technique in such a field. In audio mounted on a vehicle, a plurality of speakers are asymmetrically arranged like a stereo with respect to a listening position. Therefore, the sound image formed by the plurality of speakers is biased. This listening position correction device, in order to correct the bias of the sound image caused by the plurality of speakers being arranged asymmetrically with respect to the listening position, in advance the time lag of the propagation of sound waves from the plurality of speakers, the bias of the sound wave attenuation. Is adjusted by the delay and gain between a plurality of signals.

[0003]

However, since the conventional listening position correcting apparatus corrects the listening position for each vehicle type equipped with audio, the time difference of the propagation of the sound wave from the plurality of speakers, the sound wave propagation. Because the bias of attenuation is adjusted by the delay and gain between multiple signals,
There is a problem that it is not possible to easily cope with the case where the type of vehicle to be installed cannot be predicted like commercial audio. That is, the arrangement of the plurality of speakers is different for each type of vehicle, and it is necessary to correct the asymmetry of the speaker regarding the listening position for each type of vehicle.

Therefore, in view of the above problems, it is an object of the present invention to provide an automatic listening position correcting device which can be used regardless of the type of vehicle equipped with an audio.

[0005]

In order to solve the above problems, the present invention corrects the bias of the sound image formed by a plurality of speakers that are arranged asymmetrically with respect to the listening position and that reproduce the electric signal from the sound source. The listening position correction apparatus includes a time difference correction delay unit, a level difference correction attenuator, a sound wave propagation time measuring unit, a time difference calculation unit, and a level difference calculation unit.

The time difference correction delay unit is installed in front of the speaker and corrects a signal delay to the speaker. The level difference correction attenuator is installed in front of the speaker and corrects the signal level to the speaker. The sound wave propagation time measuring means detects the rising of the test sound signal based on the test sound signal from the sound source and measures each propagation time between each of the plurality of speakers and the listening position.

The time difference calculation unit calculates the difference between the respective propagation times and sets the difference between the propagation times in the time difference correction delay unit as a correction amount of the signal delay. The level difference calculation unit obtains the distance between each speaker and the listening position from each propagation time, and sets the signal level correction amount in the level difference correction attenuator from this distance.

[0008]

According to the automatic listening position correcting apparatus of the present invention, the rising time of the test sound signal is detected with reference to the test sound signal from the sound source, and each propagation time between each of the plurality of speakers and the listening position is increased. The difference between the propagation times is measured, and the difference between the propagation times is set in the delay unit for correcting the time difference as the correction amount of the signal delay, and the distance between each speaker and the listening position is obtained from each propagation time. , The attenuation of the sound wave that is inversely proportional to the square of this distance is set in the level difference correction attenuator as the correction amount of the signal level, so that the sound image is biased when the speaker is arranged asymmetrically with respect to the listening position. Can be corrected, and a normal stereo feeling can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a listening position automatic correction device according to an embodiment of the present invention. As shown in the figure, the listening position automatic correction device 20 is used by being incorporated in an audio 100 mounted on a vehicle as an example. First, the audio 100 will be described. The audio 10
Reference numeral 0 denotes a CD player, a radio tuner, a cassette deck, etc., and a sound source 101 that outputs left and right stereo digital signals, and D / A converters 102 and 103 (converts digital signals from the sound source 101 into analog signals, respectively). Digital to Analog Converter) and power amplifiers 104 and 105 connected to the D / A converters 102 and 103 for converting, respectively, for driving a speaker.
And speakers 106 and 107 connected to the power amplifiers 104 and 105, respectively, and directed to the inside of the vehicle compartment 200 and attached to the left and right doors. Sound source 101
For the correction of the listening position, a test signal such as a simple impulse is used for.

The listening position automatic correction device 20 is provided at the listening position (both ears) of the asymmetric driver's seat or passenger seat in the passenger compartment 200, and is a test reproduced by the speakers 106 and 107 and propagated in the passenger compartment. Left and right microphones 1 and 2 for capturing sound, amplifiers 3 and 4 connected to the microphones 1 and 2, respectively, for amplifying electric signals obtained by converting captured sound, a sound source 101, and D / A converters 102 and 103 for converting. And delay units 5 and 6 for correcting the time difference, which are provided respectively between
Level difference correction attenuators 7 and 8 which are provided in the subsequent stage of the time difference correction delay units 5 and 6 and which vary the gain.
And the delay time to be set in the time difference correction delay sections 5 and 6 connected to the amplifiers 3 and 4 and the test sound of the sound source 101 as a reference, and set in the level difference correction attenuators 7 and 8. A rise detection and time difference / level difference calculation unit 9 for calculating a gain is provided. Next, rise detection and time difference / level difference calculation unit 9
Will be explained.

FIG. 2 is a diagram showing the structure of the rising edge detection and time difference / level difference calculation unit shown in FIG. The rise detection and time difference / level difference calculation unit 9 shown in the figure first comprises a sound wave propagation time measuring means 90. The sound wave propagation time means 90
Is connected to the sound source 101, and timers 91 and 92 for resetting and starting time measurement by generation of a test sound signal
And rise detectors 93 and 94, which are connected to the amplifiers 3 and 4 respectively, detect the rise of the test sound captured by the left and right microphones 1 and 2, and stop the time measurement of the timers 91 and 92 by the rise signal. And. A threshold VR having a level lower than the rise of the test sound signal is determined in the rise detectors 93 and 94, and the point at which the test sound signal first crosses the threshold is detected as the rise. Alternatively, the first peak beyond the threshold may be set as the rising edge.

FIG. 3 is a diagram for explaining the time required for a sound wave to propagate from the left and right speakers to the left and right microphones. As shown in this figure (a), in the timer 91, the measurement time is started by the sound source 101 and stopped at the rise of the test sound signal detected by the rise detector 93, and the obtained measurement time tR is the right speaker 106. From the right microphone 2 to the right microphone 2. Similarly, as shown in FIG. 9B, in the timer 92, the measurement time is started by the sound source 101 and the rise detection unit 9 starts.
The measurement time is stopped by the rise of the test sound signal detected in 4 and the obtained measurement time tL is the time for the sound wave to propagate from the left speaker 107 to the left microphone 1.

Next, the rise detection and time difference / level difference calculation unit 9 includes a time difference calculation unit 95. The time difference calculation unit 95 obtains the time difference tL-tR from the measured times tR and tL obtained by the timers 91 and 92, and the difference between the delay amounts of the time difference correction delay units 5 and 6 becomes the time difference tL-tR. The amount of delay is set like this.

The rise detection and time difference / level difference calculation unit 9 includes a level difference calculation unit 96. The level difference calculation unit 96 measures the measurement time tR obtained by the timers 91 and 92.
And tL, the distance DR between the speaker 106 and the microphone 2 and the distance DL between the speaker 107 and the microphone 1 are obtained as follows. DR = tR xv DL = tL xv where v is the speed of sound.

Further, assuming that the propagation attenuation amounts attenuated during propagation of the sound waves through the distances DR and DL are VR and VL, respectively, and the condition that the propagation attenuation amount of the sound waves is due to diffusion is set as follows. VR ∝1 / DR ² = 1 / (tR × v) ² VL ∝1 / DL ² = 1 / (tL × v) ^{2 The} level difference calculating unit 96 has a gain 1 of one of the level difference correcting attenuators 7 and 8. .0, VR and VL on the other side
The ratio is set as the gain. The time difference calculation unit 95 and the level difference calculation unit 96 are formed in a CPU (central processing unit).

FIG. 4 is a flow chart for explaining a series of operations of the rising edge detection and time difference / level difference calculation section. In step 1 shown in the figure, it is judged whether or not there is a request for correction of the listening position from the outside. Request that there is a correction request when the audio is installed. In step 2, if there is a correction request, the time difference calculation unit 95 calculates the difference in propagation time as the correction amount of the signal delay as described above and sets it in the time difference correction delay units 5 and 6.

In step 3, the distance between each speaker and the listening position is obtained from each propagation time as described above, and the attenuation of the sound wave inversely proportional to the square of this distance is used as the correction amount of the signal level to correct the level difference. Set to. In step 4, if there is no correction request in step 1, it is determined that the correction is completed, and the reproduced sound of the CD player, the radio tuner, the cassette deck, etc. from the sound source 101 is formed. In this way, it becomes possible to automatically correct the bias of the sound image at the listening position.

[0018]

As described above, according to the present invention, the rising time of the test sound signal is detected with reference to the test sound signal from the sound source, and each propagation time between each of the plurality of speakers and the listening position is determined. The difference between the propagation times is measured, the difference between the propagation times is set as the correction amount of the signal delay in the time difference correction delay unit, and the distance between each speaker and the listening position is obtained from each propagation time. Since the attenuation of the sound wave that is inversely proportional to the square of is set in the level difference correction attenuator as the correction amount of the signal level, it is possible to correct the bias of the sound image when the speaker is arranged asymmetrically with respect to the listening position. It becomes possible to obtain a normal stereo feeling.

[Brief description of drawings]

FIG. 1 is a diagram showing a listening position automatic correction device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a rising edge detection and time difference / level difference calculation unit in FIG.

FIG. 3 is a diagram illustrating a time required for a sound wave to propagate from a left and right speaker to a left and right microphone.

FIG. 4 is a flowchart illustrating a series of operations of a rising edge detection and time difference / level difference calculation unit.

[Explanation of symbols]

 1, 2 ... Microphone 5, 6 ... Delay unit for time difference correction 7, 8 ... Attenuator for level difference correction 9 ... Rise detection and time difference / level difference calculation unit 20 ... Listening position automatic correction device 90 ... Sound wave propagation time measuring means 95 ... Time difference calculation unit 96 ... Level difference calculation unit 100 ... Audio 101 ... Sound source 106, 107 ... Speaker

Claims (1)

[Claims] 1. A listening position correction device that corrects a bias of a sound image formed by a plurality of speakers that reproduce a signal from a sound source and that is arranged asymmetrically with respect to the listening position, the speaker being installed in front of the speaker. Difference correction delay unit (5, 6) for correcting the delay of the signal to the speaker, and a level difference correction attenuator (7, 8) installed before the speaker for correcting the level of the signal to the speaker.
And sound wave propagation time measuring means (9) for detecting the rising of the test sound signal based on the test sound signal from the sound source and measuring each propagation time between each of the plurality of speakers and the listening position.
0), and a time difference calculation unit (95) for calculating the difference between the respective propagation times and setting the difference between the propagation times as the correction amount of the delay of the signal in the time difference correction delay unit (5, 6), Find the distance between each speaker and the listening position from the propagation time,
An automatic listening position correcting device, comprising: a level difference calculating unit (96) for setting the level correction amount of the signal in the level difference correcting attenuator (7, 8) from this distance.