JPS5953000A - Stereophonic reproducing device - Google Patents

Abstract

PURPOSE:To prevent deterioration in spreading feeling even at a position leaned to one side between left and right speakers and to obtain sufficient stereophonic feeling, by giving a phase delay to left and right channel signals to supply said signals to left and right speakers and attenuating the addition signal of left and right channel signals and supplying it to a center speaker positioned between left and right speakers. CONSTITUTION:When left and right channel signals L, R are supplied, left and right channel signals L, R to which a phase delay is given are supplied to left and right speakers 9, 10 while the addition signal of left and right signals L, R having no phase delay is supplied to a center speaker 14. Accordingly, the reproduced sound for addition signal of the left and right channel signals L, R reproduced from the center speaker 14 reaches a hearer earlier than the reproduced sound of the left and right channel signals L, R reproduced from the left and right speakers 9, 10. Conditions of precedent sound localization is applicable between the reproduced sounds of the left and right speakers 9, 10 and the reproduced sound of the center speaker 14. Consequently, even when a hearer is at a leaned position, and good stereophonic feeling can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stereo playback device, and more particularly to a stereo playback device that can provide a sufficient stereo feeling even at a position away from the midpoint between left and right speakers that play back stereo signals.

In a stereo reproduction device, a good stereo effect can be obtained at a position halfway between the left and right speakers (a position on the bisector of the left and right speakers), but a sufficient stereo effect cannot be obtained outside this position.

Particularly in car stereos, the listener's position (driver's seat, passenger's seat) is fixed, and it may not be possible to position the listener between the left and right speakers, making it impossible to obtain a sufficient stereo effect.

For this reason, for example, as shown in FIG. 1, a plurality of speakers 3... are arranged between the left and right speakers 1 and 2, and left and right stereo signals are distributed to these speakers 3... by an impedance element 4. Stereo playback devices have been proposed that are configured to provide.

However, in the above stereo playback device, the speaker 1
．． 2. Unless the installation interval between speakers 3 and 3 is increased, the sense of spaciousness of the sound will be reduced due to the volume from the middle speaker 3. is not suitable. In addition, when implementing the stereo playback device with the above configuration using three speakers, the stereo feeling at a position closer to either one of the left and right speakers 1 and 2 (hereinafter referred to as an offset position) is In order to improve the sound quality, if the volume of the speaker 3 located at the center is increased, the sound image that should be localized at the center will be moved slightly closer to the center, but the sense of spaciousness will deteriorate.

The present invention has been made in view of the above circumstances, and its purpose is to provide a stereo playback device that provides a sufficient stereo sound without deteriorating the sense of spaciousness even in a position where the left and right speakers are offset. It is to be.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing an example of a stereo playback device of the present invention. In the figure, reference numerals 5 and 6 are all-pass filter type phase shifters, 7 and 8 are power amplifiers, and 9 and 10 are left and right speakers.

The phase shifter 5 gives a predetermined phase delay to the left channel signal. The phase-delayed left channel signal is supplied to the left speaker 9 by the power amplifier 7. Phase shifter 6
gives a predetermined phase delay to the right channel signal H. The right channel signal R given a phase delay is sent to the power amplifier 8.
is supplied to the right speaker 10.

Further, 11 is an adder, 12 is an attenuator, 13 is a power amplifier, and 14 is a center speaker.

The kT adder 11 adds the right channel signal R and the left channel signal R before being given a phase delay in phase. This added left and right channel signals.

After R is reduced by a predetermined attenuation amount At in the attenuator 12,
The signal is supplied via a power amplifier 13 to a center speaker 14 located between the left and right speakers 9°10.

FIG. 3 is a circuit diagram showing an example of the above-mentioned phase shifters 5 and 6, which is constructed by connecting the necessary number of phase shift circuits 15 in series in which the amplitude frequency characteristic is flat and the phase frequency characteristic is delayed from 0 to π. ing. This phase shift circuit 15 is composed of an operational amplifier 16, a resistor R, and a capacitor C. Frequency f with phase delay πh. is expressed by the following equation.

fo = '/2yrRO The shift of each stage, f of the fourth circuit 15. to an appropriate frequency (for example, in the case of 10 stages, from 100Hz to 100Hz every IK
Hz) to obtain the required phase delay l characteristic. In addition, J'. may be the same.

Next, the operation of a practical example will be explained.

When the left and right channel signals R, R are supplied, the left and right speakers 9 and 10 are supplied with the left and right channel 1 signal, I (with a phase delay), whereas the center speaker 14 is supplied with a phase delay. Left and right channel signals without delay, H
The addition signal can be supplied.

Therefore, the left and right channel signals reproduced from the center speaker 14, the reproduced sound corresponding to the H addition signal, and the left and right channel signals reproduced from the left and right speakers 9 and 1o reach the listener before the H reproduced sound. , the condition for preceding sound localization is established between the sound reproduced by the left and right speakers 9, 100 and the sound reproduced by the center speaker 14. Therefore, the center sound image C can be moved approximately to the center of the left and right sound images A and B (
The center speaker 14 can also be placed in this position.
The sense of spaciousness is no longer reduced by the reproduced sound emitted from the listener, and a good stereo feeling can be obtained even if the listener is in a lopsided position.

Now, if the signal voltage of the central sound image C is ec1 and the signal voltage of the left and right channel signal H is eL+OR, then eL=ea=6c/2.

On the other hand, for example, the signal voltage e4 of the leftmost sound image A is eL=8
．． It is divided into left and right channels by one channel, as shown in 2.6R=0.

Assuming that the voltage applied to the speakers 9, 10.14 is e'L + e'R+ ``C, and the attenuation amount At is = 102°, for the central sound image C, θ'g- ec/2, e'(H=k * (13R++
3L) -ke□, el'L=ec/2.

For the leftmost sound image A, e'n=0X e'c=*(on+et,)=kee
4, +11'L=6μ.

If k ÷ 0.63, that is, Aj = 4 dB, then for the central sound image C, e /c' is +2d as well as e'L.
B is large, and e/c is θ for the leftmost sound image A
'The L height is also reduced by 4 dB. That is, regarding the sound 1 of the medium fire C, the leading sound side is radiated at a level 2 dB higher, so together with the leading sound effect, the sound image can be localized near the speaker 14. Furthermore, regarding the leftmost TV sound image A, the level of the speaker 9 is 4 relative to the speaker 14.
(Because the IB is high, this level difference is a problem.) The sound image can be localized near the speaker 9. Similarly, regarding the sound image B at the right end, the level of the speaker 1° is 4 dB higher than that of the speaker 14, and this level difference allows the tone to be localized near the system beaker 1o.

The phase delays of the left and right channel signals and H are adjusted depending on the position of the listener.If the phase delays of the left and right channel signals and H are made the same, the sound will be the same whether the listener is at a position off to the right or to the left. You can get a stereo feeling. Adjustment of the phase Il deviation can be performed using, for example, a plurality of phase shift circuits 1.
This can be easily done by simply short-circuiting the capacitor C of a predetermined phase shift circuit 15 among the phase shift circuits 15.

Note that if no phase delay is given to the left and right channel signals H, and if no attenuation is given to the added signal of the left and right channel signals H, the sound image B at the right end is is shifted to the left, and the sound image C, which is still in the center, is also shifted to the left and the level increases, resulting in reproduced sound that does not provide a sense of spaciousness and stereo as a whole.

Figure 4 is a phase delay time characteristic diagram when 12 stages of the above-mentioned phase shift circuit 1S are provided. For example, at a frequency of 1 KHz, the delay time is approximately 4 mg.
A phase delay time of .

If the number of stages in the phase shift circuit 15 is small, the delay time will be short; on the other hand, if the number of stages is increased unnecessarily, the phase will shift by one cycle and the delay time will become short.
The number of stages of the phase shift circuit 15 is preferably about 12.

FIG. 5 shows the localization data of the central sound image when the pulse waveform is input as each frequency when the delay time is set to 6 mS, 8 mS, and 10 m5. -r'<1. ing. The listening position is near the right speaker 10, as shown in FIG. Also, among each frequency, data (1
) is the left and right channel signal, and the R is manually positioned in the center.
It shows where the sound image C is actually localized, and data (2) shows the actual localization position of the sound image H, which should be established at the center when the left channel signal R is input.

It is clear from the figure that the sound image C is located approximately at the center. Note that the symbol o-0 in the data indicates that the localization is in the section between the small diameter cross mark and the large diameter circle mark, but the localization is strongly localized on the large diameter circle side. For example, when the input frequency is 2 KHz, data (2) indicates that the sound is localized in the area between the speaker 14 and the speaker 10, but the sound is localized strongly to the right side of the speaker 10w.

In the above embodiment, the operational amplifier 16 is used to configure the phase shift circuit 15, but the operational amplifier 16 may be a transistor, or the entire circuit may be integrated into an IC to reduce costs and make it more compact.

The present invention is not limited to car stereos, but can also be applied to ordinary stereos.

As explained above, according to the present invention, the left and right channel signals are supplied with a phase delay to the left and right speakers, and the added signal of the left and right channel signals is attenuated to the center speaker located between the left and right speakers. Since the sound is supplied to the speakers, a sense of spaciousness can be obtained without increasing the spacing between the speakers, and a stereo sound can be obtained even in a lopsided position without deteriorating the sense of spaciousness.

Since a phase shifter is still used, there is no problem and there is no increase in cost. That is, when using a delay circuit instead of a phase shifter, B
When using a BD, there is a decrease in S/N, and there is also an increase in cost due to A/D conversion and digital delay, but this does not occur with the present invention.

Further, if a plurality of phase shift circuits having the same or different frequencies that produce a phase delay of 4 (!l-1π/2) are connected in series, the phase delay can be easily adjusted.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional stereo playback device, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a circuit diagram showing an example of a phase shifter, and Fig. 4 is a phase delay time. Characteristic diagram, 5th
The figure shows the localization data of the sound image, and FIG. 6 shows the sample listening position. 5.6... Phase shifter, 9.10... Left and right speakers,
11... Adder, 12... Attenuator, 14... Center speaker, 15... Phase shift circuit, L, R... Left and right channel signals, A, B, (3... Sound image. Patent Applicant: Pioneer Corporation Figure 1 Figure 2 Figure 3° Xi ILILI IK
IOK (Hz) Figure 5 Figure 6 Procedural amendment (voluntary) March 9, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of case '11B 1981 Patent Application No. 163
085 No. 3, Relationship with the case of the person making the amendment Patent applicant address: 1-4 Mesho, Meguro-ku, Tokyo Name (5)
01) Pioneer Corporation ÷←→4 4. Agent 5, date of amendment order Showa year, month, day, 6
, Number of inventions increasing due to amendment (1) Meiwakan's "Detailed explanation of l"U≦h;, -mu゛)
7. Contents of the amendment that is subject to amendment (Claim No. 57-163085) 1. rK+o, l described in Ministry of Specification, page 1, line 6 to page 1, line 1T'
i3・・・・・・・・・4aBJ, <nashi,” is corrected in the legal text. “If K÷0.32, that is, Mut=10tlB,
For the central sound image C, e”o is 4 dB lower than a’L.
e'o is small, and e'o is also 10 dB smaller than o'L with respect to the left-sided image. In other words, the central sound image C
For this, either the leading dorsal side emits at a level 4 dB lower, or the sound image can be localized near the speaker 14 by the leading sound motion floor. Also, regarding the sound image on the far left,
The level of speaker 9 is 1θdB relative to speaker 14
Since this level difference is smaller than that of the previous speaker, it is possible to localize one body near the speaker 9. rightmost note g
*For B as well, the level of speaker 10 in the stubble is 10 compared to speaker 14 (IB, don't omit it.) 2. If you don't give it, = 2 ``Figure...'' is corrected to ``If not given, if the listening position is to the left, stripe 2 figure...''. 3. From the 8th negative line 20 to the 1st line of page 9. Part 1 of item 6C
- On the contrary, ``optimal'' is corrected to ``on the contrary, if the number of stages is increased or increased unnecessarily, the sound image will spread and become unstable, so it is suitable for M.'' 4, 1#I 9th negative line 11th to 13th negative line "lta...indicates." Correct it to the right when you input it, and the sound image B's smiling face has a warm foot position.'' 5. 3 Correct ``by doing...'' to ``by using BBD.'' ” and the shaft is fixed. T. Add the code “9” to the 2nd map as if it is undistributed. Percentage applicant Pioneer Co., Ltd.

Claims (2)

[Claims] (1) In a stereo reproduction device that reproduces left and right channel signals independently from speakers, a phase shifter that gives a phase delay to the left and right channel signals and supplies them to the left and right speakers, and a phase shifter that supplies the left and right channel signals to the left and right speakers; an attenuator that attenuates the output signal of this adder by a predetermined amount, and a center speaker that reproduces the output signal of this attenuator in left and right speaker music. A stereo playback device characterized by: (2) Claims characterized in that the phase shifter is constructed by cascade-connecting a plurality of phase shifters having the same or different frequencies that produce a phase delay of π. The stereo playback device according to item 1.