JPH10150700A - Listening position adjusting method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a listening position adjusting method and its device fixing the position of a sound image to a desired position and keeping the balance of a sound are from low-frequency sound to high-frequency sound despite of changing the position to which the position of the sound image is fixed. SOLUTION: A DSP(digital signal processor) 15 separates a front/left side audio signal, a front/right side audio signal, a rear/left side audio signal and a rear/right side audio signal from an audio signal inputted from an A/D converter 14 by a signal separating part 15a, frequency characteristic is corrected by an equalizer 15b and individually is delayed by a delay processing part. At this time, the DSP 15 increases the output level of the low frequency component (not higher than 200Hz, e.g.) of a rear-side audio signal according to the delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a listening position adjusting method and a listening position adjusting apparatus for localizing a sound image at a predetermined position in accordance with a listening position in an in-vehicle audio system or the like.

[0002]

2. Description of the Related Art In a vehicle audio system, generally, as shown in FIG. 4, a total of four speakers are provided on the left and right sides of a listener (eg, driver or passenger) D on the front and rear sides. FL, FR, RL, and RR are arranged. Further, a bass speaker called a subwoofer may be arranged between the two speakers RL and RR on the rear side.

[0003] In a car audio system, a listener D uses these speakers FL, FR, R
Since the user does not sit at a position equidistant from L and RR, simply amplifying and outputting the sound from a sound source (tuner or cassette tape player, etc.) shifts the position where the sound image is localized from the front of the listener. . Therefore, in recent audio systems for vehicles, each speaker FL, FR,
Controls the delay time of the audio signal sent to RL, RR,
The sound image can be localized at a desired position of the listener D and the sound can be given a spaciousness.

[0004] In recent years, audio systems have been digitized, and audio signals are digitally processed. Therefore, it is relatively easy to control the position where the sound image is localized by delaying the signal as described above. For example, by delaying the signals sent to the rear speakers RL and RR, as shown by the broken line in FIG. 4, the sound is heard as if the speakers RL and RR are behind the actual position, and the listener D
Can be localized in front of the sound image.

[0005]

However, the conventional in-vehicle audio system has the following problems. That is, the sound output from the front speakers FL and FR becomes more important as the sound image is localized forward. However, in general, in a vehicle audio system, the front speakers FL and FR are not used due to the space required for installation.
Are relatively small in diameter. For this reason, it is difficult for bass sounds to be output from the front speakers FL and FR. Therefore, in the conventional on-vehicle audio system, if the sound image is localized in front of the listener D, the bass sound is insufficient as a whole, resulting in a so-called thin sound.

Accordingly, an object of the present invention is to provide a listening position in which a sound image can be localized at a desired position and a sound range from low to high can be maintained even when the position at which the sound image is localized is changed. An adjustment method and a listening position adjustment device are provided.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of adjusting a listening position of an audio system in which a plurality of speakers are arranged on a front side and a rear side, respectively. It is characterized in that the output level can be adjusted for each frequency band by dividing into frequency bands, and the low frequency component of the audio signal sent to the rear speaker is changed according to the delay amount of the audio signal sent to the rear speaker. The problem is solved by the following listening position adjustment method.

[0008] Further, the above-described problem is caused by a delay processing unit for individually delaying a front-side audio signal and a rear-side audio signal, and dividing the front-side audio signal and the rear-side audio signal into a plurality of frequency bands. An equalizer unit that individually adjusts the volume level of the signal in each frequency band, and controls the equalizer unit with an increase in the delay time of the rear audio signal to control the frequency band of the low frequency side of the rear audio signal. The problem is solved by a listening position adjusting device having a control unit for increasing the output level.

The operation of the present invention will be described below. In the present invention, the control section controls the delay processing section and the equalizer section, and increases the low-frequency component of the rear audio signal as the delay time of the signal sent to the rear speaker increases. Low-frequency sounds have a weak directivity, and therefore have the property of making it difficult to sense the direction of the sound source. Therefore, even if the low-frequency component of the sound output from the rear speaker is increased, the sound image can be localized in front of the listener without causing a sense of incongruity. In the present invention, the output level in the low-frequency band of the rear audio signal is increased by increasing the delay time of the rear audio signal by utilizing such sound properties. Therefore, it is possible to make up for the lack of bass that occurs when the sound image is localized forward, and to maintain the balance of the sound range from bass to treble.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) FIG. 1 is a block diagram showing a listening position adjusting device according to a first embodiment of the present invention. This listening position adjusting device includes three input terminals 11a, 11b, 11c. These input terminals 11a, 11b, 11c include, for example, a tuner,
Audio devices such as a CD player and an MD player are connected, and audio signals (left channel audio signal and right channel audio signal) are input from these audio devices.

The audio signals input to the input terminals 11a, 11b, 11c
a, 12b, and 12c, and are input to the selector 13. The selector 13 has three input terminals 11 a and 1 based on a signal from the microcomputer unit 10 described later.
Any one of the audio signals input from 1b and 11c
Selectively output one. The A / D converter 14 A / D (analog / digital) converts the audio signal output from the input selector 13. The digital signal output from the A / D converter 14 is input to a DSP (digital signal processor) 15.

The DSP 15 has a signal separation section 15a, an equalizer section 15b, and a delay processing section 15c.
The signal separation unit 15a digitally processes the signal input through the A / D converter 14 and separates the signal into a front left audio signal, a front right audio signal, a rear left audio signal, and a rear right audio signal. The equalizer unit 15b divides the signal separated by the signal separation unit 15a into a plurality of frequency bands by frequency, adjusts the output level of each frequency band, and corrects the frequency characteristics. The delay processing unit 15 includes a front left audio signal,
The front right audio signal, the rear left audio signal, and the rear right audio signal are delayed. DSP15
Determines the delay time of each signal in accordance with a parameter input from the microcomputer unit 10 described later, controls the equalizer unit 15b in accordance with the delay time, and controls the low frequency (for example, 200 Hz or less) of the rear audio signal. Change the output level of

The D / A converter 16a converts the digital front left audio signal and front right audio signal output from the DSP 15 into analog signals. Similarly, the D / A converter 16b includes a DSP
The rear left audio signal and the rear right audio signal output from the converter 15 are converted into analog signals.

The front volume circuit 17a adjusts the output level of the analog front left audio signal and the front right audio signal output from the D / A converter 16a according to the signal from the microcomputer unit 10. The audio signal output from the front volume circuit 17a is amplified by the amplifier 18a, transmitted to the front left speaker and the front right speaker via the output terminal 19a, and output as sound.

The rear volume circuit 17b has a D / D
The output level of the analog rear left audio signal and the rear right audio signal output from the A converter 16b is adjusted. The audio signal output from the rear volume circuit 17b is amplified by an amplifier 18b, and output from an output terminal 19b.
The signal is transmitted to the rear left speaker and the rear right speaker via b, and is output as sound.

The microcomputer unit 10 includes an operation unit 20
It is connected to the. The input selector 13 and the A / D converter 14 are controlled based on a user's instruction transmitted through the operation unit 20, the delay time and equalizing of signals in the DSP 15 are controlled, and the volume circuit is controlled. 17a and 17b are controlled. Note that a plurality of listening positions are preset in the microcomputer unit 10, and the user can set a desired listening position from these preset listening positions using the operation unit 20. For example, when the user selects the driver's position, the microcomputer unit 10 outputs a preset driver position parameter to the DSP 15. The DSP 15 determines the delay processing unit 1
The delay time of each signal at 5c is determined. As a result, the sound source is localized in front of the driver's seat. When the user selects a navigation position, the microcomputer unit 10 outputs a preset navigation position parameter to the DSP 15. DS
P15 determines the delay time of each signal in the delay processing unit 15c based on this parameter, so that the sound image is localized in front of the passenger seat.

Hereinafter, a method of adjusting the listening position in the listening position adjusting apparatus according to the present embodiment configured as described above will be described. The microcomputer unit 10 controls the selector 13 based on a user's instruction input via the operation unit 20, and transmits only an audio signal from a desired sound source to the A / D converter 14.
Further, the microcomputer unit 10 outputs the parameters of the listening position to the DSP 15 based on the user's instruction. For example, when the user selects the driver's position, the microcomputer unit 10 outputs a parameter for the driver's position to the DSP 15. The DSP 15 adjusts the delay time of the signal in the delay processing unit 15c based on these parameters so that the sound image is localized in front of the driver's seat.

The operation unit 20 allows the user to move the sound image.
Is operated, the microcomputer unit 10
5 is instructed to change the delay time. To move the sound image forward, the DSP 15
The delay time of the signal is increased by an instruction from 0, and the low-frequency component (for example, 200 Hz or less) of the rear audio signal is increased according to the delay time.

For example, as shown in FIG. 2, the microcomputer unit 10 has a delay time of the rear audio signal of zero.
Assuming that the output level of the low-frequency component of the rear-side audio signal at time 0 is 0 dB, the output level of the low-frequency component of the rear-side audio signal when the delay time is 0.3 ms is +1.
The output level of the low-frequency component of the rear audio signal when the delay time is 0.5 ms is +2 dB, and the output level of the low-frequency component of the rear audio signal when the delay time is 0.6 ms is +3 dB. Thus, as the delay time is increased, the output level of the low-frequency component of the rear audio signal is increased. On the other hand, when moving the sound image backward, the DSP 15
, The signal delay time is reduced, and the low-frequency component of the rear audio signal is reduced.

A sound having a low frequency has a property that the directivity is weak and it is difficult to sense the direction of the sound source. Therefore, even when the low-frequency component of the rear audio signal is increased when the sound image is moved forward, the middle and high frequency sounds are not generated by the front speaker F.
Since the sound image comes out of L and FR, the sound image is localized in front of the listener D and does not feel uncomfortable. Thus, according to the listening position device of the present embodiment, even if the sound image is localized at a desired position, music or the like can be heard with balanced frequency characteristics from low to high.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described.
An embodiment will be described. Note that, also in the present embodiment, description will be given with reference to FIG. In the present embodiment, in addition to increasing the output level of the low frequency component as the delay time of the rear audio signal is increased in the DSP 15, the cutoff frequency of the high frequency side of the rear audio signal is reduced. It shifts to. For example, as shown in FIG. 3, when the delay time of the rear audio signal is 0, the cutoff frequency on the high frequency side of the rear audio signal is set to 20 kHz, and the delay time of the rear audio signal is 0.3 ms. When the cut-off frequency is 15 kHz, the cut-off frequency is 13 kHz when the delay time of the rear audio signal is 0.5 ms, and the cut-off frequency is 11 when the delay time of the rear audio signal is 0.6 ms.
kHz.

As described above, the high-frequency sound output from the rear speaker is cut as the sound image is localized forward, so that the sound becomes clearer. In the present embodiment,
As the delay time of the rear audio signal in the delay processing unit 15c is increased by the DSP 15, the output level of the low-frequency component of the rear audio signal is increased, and the high-frequency component of the rear audio signal is further cut. Lower the off frequency. As a result, even when the sound image is localized at a desired position, the balance from the high range to the low range is further improved as compared with the first embodiment, and the music can be heard with clear sound quality.

In the above embodiment, the output level of the low frequency component of the audio signal transmitted to the rear speaker is increased or decreased in accordance with the increase or decrease of the delay time of the signal transmitted to the rear speaker. However, in the case of an audio system having a subwoofer on the rear side, the output level of a low-frequency signal transmitted to the subwoofer may be increased or decreased.

[0024]

As described above, according to the present invention,
Since the output level of the low-frequency component of the rear audio signal increases as the delay time of the rear audio signal increases, the sound image is localized forward by using a relatively small-diameter front speaker. In addition, the shortage of bass can be compensated, and the balance of the sound range from low to high can be maintained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a listening position adjusting device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a delay time of a rear-side audio signal and an amplification factor of a low-frequency component of the rear-side audio signal.

FIG. 3 is a diagram illustrating a relationship between a delay time of a rear audio signal and a cutoff frequency on a high frequency side of the rear audio signal in the listening position adjustment device according to the second embodiment of the present invention.

FIG. 4 is a schematic diagram showing positions of speakers of the on-vehicle audio system.

[Explanation of symbols]

 Reference Signs List 10 microcomputer unit 11a, 11b, 11c terminal 12a, 12b, 12c buffer amplifier 13 input selector 14 A / D converter 15 DSP 15a signal separation 15b equalizer unit 15c delay processing unit 16 D / A converter 17a, 17b volume circuit 18 Amplifier 19a, 19b Output terminal 20 Operation section

Claims (3)

[Claims] 1. A method of adjusting a listening position of an audio system in which a plurality of speakers are arranged on a front side and a rear side, respectively, wherein an audio signal to be sent to a front side speaker and a rear side speaker is divided into a plurality of frequency bands, and A listening position adjusting method, wherein an output level is adjustable every time, and a low-frequency component of an audio signal sent to the rear speaker is changed according to a delay amount of the audio signal sent to the rear speaker. 2. A delay processing unit for individually delaying a front-side audio signal and a rear-side audio signal, and a signal in each frequency band by dividing the front-side audio signal and the rear-side audio signal into a plurality of frequency bands. And an equalizer unit for individually adjusting the volume level of the rear audio signal, and increasing the delay time of the rear audio signal to control the equalizer unit to increase the output level of the rear audio signal in the lower frequency band. A listening position adjusting device, comprising: a control unit. 3. The control section controls the equalizer section with an increase in delay time of the rear-side audio signal to increase an output level of a low-frequency side frequency band of the rear-side audio signal, and The listening position adjusting device according to claim 2, wherein a cutoff frequency on a high frequency side of the rear side audio signal is reduced.