DE2422471A1 - MULTI-CHANNEL SOUND SIGNAL RECORDING AND / OR PLAYBACK SYSTEM - Google Patents

Description

It 2882

1. Dr. Duane H. Cooper, Champagne, Illinois, USA

2. NIPPON COLUMBIA KABUSHIKIKAISHA, Tokyo, Japan

Multi-channel audio signal recording and / or -Playback system

The invention relates to a multi-channel audio signal recording and / or playback system, generally known as a four-channel stereo system is known and for multiplex recording of several main channel signals and several carrier-modulated Sub-channel signals in a single sound groove on a record and / or for reproducing the recorded signals suitable is.

A known system of this type is the "Universal Matrix system" (hereinafter referred to as UM-Sysfeem), which is used by Duane H. Cooper was suggested.

The UM system is with a common monaural system and a standard 2-channel stereo system compatible and is able to reproduce sound generators with high quality; it makes the definition clearer Sound images are safe and allow speakers to be freely arranged, making it very useful in practical use advantageous.

In the case of the multi-channel sound system such as the UM system, the one However, the following problems are encountered:

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One of these problems is that since the pass band of the carrier subchannel signal is limited by the to limit the required frequency band of the system as a whole, in the event of overmodulation a cut-off distortion occurs.

Another problem is the generation of beat distortion in a demodulated subchannel signal as a result Cross-talk between the auxiliary carrier channels in the recording system and mainly in the playback system.

Another problem is the generation of cross talk from the main channel signal to the sub-channel signal (imiblgaiden referred to as outward crosstalk), which is caused by a groove errors and tracking distortion in the playback system is caused.

The invention is based on the object of providing a multi-channel audio signal recording and / or playback system free from the clipping distortion that caused by limiting the frequency bandwidth of the subchannel signal caused by the beat distortion is free due to crosstalk between the subchannel signals, and that from the influence of the forward communication caused by the main channel.

Solutions to this problem and appropriate configurations of the invention emerge from claims 1 to 12.

The invention is explained below with reference to Figures 1 to, for example. It shows:

Figure 1 is a block diagram of an example of a recording system for multi-channel audio signals,

FIG. 2 vector diagrams of subchannel signals which are encoded in the plate cutting device,

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Figures 3A and 3B are graphs showing recording RIAA characteristics emerge from main channel signals,

Figure 4 diagrams to explain the multi-channel audio signal recording system,

FIG. 5 is a block diagram of an example of a multi-channel audio signal reproduction system;

Figure 6 is a diagram showing the interference with the subchannel signal and subchannel signal modulation curves

FIG. 7 is a vector diagram showing the difference between sub-channel signals TT and TQ,

FIG. 8 is a block diagram showing an example of a recording system according to the invention;

FIGS. 9 and 10 are block diagrams of further examples of the recording system according to the invention,

FIG. 11 diagrams of frequency spectra to explain the example of FIG. 10,

Figure 12 is a block diagram showing another example of the recording system of the invention;

FIG. 13 is a block diagram of a further example of a playback system according to the invention,

Figure 14 is a block diagram of another example of the recording systor of the invention;

Figs. 15 and 16 are diagrams for explaining the recording system in Figs. 14, and

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Fig. 17 is a block diagram showing a reproducing system corresponding to the recording system in Fig. emerges.

For a better understanding of the invention, the UM system will first be described as applied to a 4-channel stereo system. Fig. 1 shows a block diagram of its recording device. 1 with a sounder is referred to, which emits four signals S__, S__, S__ and S _n ^. These four signals

Yyy? Kr u r> .Kd

are obtained, for example, from microphones which are arranged in correspondence with the loudspeakers LF, RF, LB and RB of a turntable shown in FIG. The electrical signals received from the microphone corresponding to the speakers LF, RF, LB and RB are denoted by S__, S__, S _T _ and S__, aekenn-

JjT Kr Jjü KxJ "

draws, the four signals are fed to an encoder 2 to generate signals TL, TR, TT and TQ corresponding to of the following equation (1) are related to each other. The signals TL and TR are called main channel signals and the signals TT and TQ are referred to as sub-channel signals.

TL = O, 924S _LF <+ 22.5 ° + O, 383S _Rp <+ 67.5 ° + O, 383S _RB <-67.5 ° + O, 924S _LB <-22.5 °

TR = 0.383S _LF <-67.5 ° + 0.924S _Rp <-22.5 ° + 0.924S ₇₅₁₃ <+ 22.5 ° + 0.383S _T _ <+ 67.5 °

TT = 1.414S _T _ <+ 135 ° + 1.414S--, <+ 45 °

Yyy? Kr

+ 1.414S ₁ ^ <-45 ° + 1.414S _LB <-135 ° TQ = 1.414S _Lp <+ 90 ° + 1.414S ^ <-90 °

_RB

1.414S _RB <+ 90 ° + 1.414S ^ <-90 °

The vectors of signals TL, TR, TT and TQ are shown in FIG.

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The main channel signals TL and TR of the encoder 2 are fed to a mixer circuit 5 via a recording equalizer 4. The characteristics of the recording equalizer 4 are indicated by the curves in Figs. 3A and 3B which are standardized as RIAA recording characteristics. The subchannel signals TT and TQ are supplied to an angle modulator 6a in order to perform angle modulation of the carrier signal fc which is output from an oscillator 6b. The carrier of the frequency fc, which is angle-modulated in this way by the sub-channel signals TT and TQ, is referred to as the modulated sub-channel signal TT ¹ and TQ '. The modulated sub-channel signals TT 'and TQ' are added to the main channel signals in the mixer circuit 5 in order to generate two transmission signals (TL + TT ¹ ) and (TR + TQ '). These two transmission signals are passed through a recording amplifier 7 to a 45-45 cutter 8, which is the same as that used for making stereo records. From the 45-45 cutter 8, the signals (TL + TT ¹ ) and (TR + TO ¹ ) are recorded on the walls of a sound groove. This is shown in FIG. The main channel signal TL and the modulated sub-channel signal TT ¹ are recorded in one wall 9L of the sound groove, and the main channel signal TR and the modulated sub-channel signal TQ ¹ are recorded on the other wall 9R.

The reproducing device of the record which has the audio signals thus recorded is shown in the form of a block diagram in FIG. A signal reproduced by a pickup 21 is sent to a preamplifier 22. The main channel signals TL and TR, which are output from the preamplifier 22 are a decoder supplied 24 through a playback equalizer 23, whose characteristics are opposite to those of the recording amplifier 4 ". The modulated sub-channel signals TT ¹ and TQ ', which from the preamplifier 22 a band-pass filter 25 are demodulated by an angle demodulator 26. The subchannel signals TT and TQ

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the decoder 24 are of the Winkeldemodulator 26 fed together with the main channel signals TL and TR to Sicmale equal to the audio signals S, ^s rj ^"s lb ¹ ^ ^{10 S} t? ^{b erzeuc? s} / output from the sound generator. 1 This Sirmale S ₁ .. ,, S _15x ,, S _TD and S _n -. Are via an amplifier 27 the

Jji; Kr ho KtS

Loudspeakers LF, RF, LB and RB of the corresponding (2 + 2) arrangement fed.

The above-mentioned problems encountered in the recording 4-channel stereo system from the carrier sub-channel VO occur, described in detail.

The first problem is limiting the size of the tolerance deviation. Overmodulation of the subchannel signals with low frequency modulation is caused when the peak frequency deviation exceeds a frequency limit determined for the modulated subchannels is. When modulating with a high-frequency signal - the modulated sub-channel signals have frequency components, that exceed the peak frequency deviation. E.g. a maximum frequency deviation such that 5% of the energy of the carrier is outside a band of 10 KHz on either side has a step shape as in 3Oa in Fig. 6 is indicated. This tendency can be shown as indicated at 30b. The demodulation distortion occurs when the modulated subchannel signals are applied to the bandpass filter 24 to remove the modulated Separate subchannel signal in the playback device. E.g. a limit at which a harmonic distortion of 5% is as indicated by a stepped curve at 31a in FIG. 6. In the event of of a symmetrical filter, the harmonic distortion has an odd order and in the case of a single one

Sideband filter, the harmonic distortion has an even order. The straight line 31b shows the general Tendency. The subchannel signal modulation curve

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should not exceed lines 30a and 30b.

A second problem is beat distortion which is caused in the modulated subchannel signals when cross talk occurs between the modulated subchannel signals. Cross-talk generally occurs when signals are recorded on and reproduced from the record. The crosstalk during recording is caused by a cutter head, a stylus, etc., and an expensive cutter head and stylus are required to remove the crosstalk. The crosstalk during reproduction is caused when the pickups pick up the signal from the sound groove of the record, and it is difficult from the manufacturer's point of view to completely eliminate the crosstalk due to the pickup. In the generation of beat distortion due to crosstalk in the carrier frequency band, if the relative phase deviation is large, non-linear, complicated harmonic distortion and cross-modulation distortion occur. If the crosstalk of the groove walls a component has the same phase, the distortion is an odd-order component, and if χ is the peak phase deviation difference, the distortion is proportional J_. (n is a positive integer). When the crosstalk is an orthogonal component, the distortion has an even order component and is proportional to J. . . (n is a positive integer. J.. is a Bessel function

Il \ X /

of the η-th order of the first kind. The distortion is proportional to the size of the crosstalk and the component ^J 3 (x) / x ^becomes maximum when χ = 3.6, the component J ^. » . becomes maximal when χ = 2.3 and the two components ^J 2 (x) / x ^{and J} 3 (x) / x ^become equal to each other when χ = 3.8. The harmonic distortion in this case is around 2% if the crosstalk is - 2OdB. A modulation index of 3.8 rads is a limit to the generation of distortion

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lower and higher orders and this is a modulation index difference, half the size of which is indicated at 32 in FIG. When the subchannel signal modulation curve exceeds line 32, the beat distortion decreases to.

A third problem is crosstalk from the main channel signal on the subchannel signal. that is generated during playback. This crosstalk is called upward crosstalk designated. Crosstalk from the subchannel signal to the main channel signal, on the other hand, is called downlink crosstalk designated. The downward crosstalk is not a problem in the case of tracking distortion however, when the subchannel signals are recorded at a constant speed. The upward crosstalk is caused by a caster angle error and a caster distortion evoked.

If the modulated subchannel signal is shifted less than the main channel signal in the upward crosstalk due to the groove angle1 error, the modulated subchannel signal is subjected to a phase modulation of 2Tr / Ac at tg0, where am is the shift of the main channel signal, Ac is the wavelength of the carrier signal and φ der Groove error angle is. For example, the upward crosstalk due to a vertical groove error angle is mainly caused by the vertical component (a difference signal component) of the main channel signal. When the main channel signals are recorded with the RIAA recording characteristics in Fig. 3, the upward crosstalk is generated in the case of a vertical groove error angle of 5 ° within the limit indicated at 33 in Fig. 6.

Although independent of the influence of the main channel signals, a distortion in the form of rumble noise in the demodulated signal due to rapid pitch fluctuations

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generated. This distortion creates a component equal the upward crosstalk. For example, the influence of 0.1% pitch fluctuations on the subchannel is indicated at 34. Therefore, the subchannel signal modulation curve should be away from lines 33 and 34.

The upward crosstalk due to the tracking distortion is transferred from the main channel signals to the sub-channel signals on the two groove walls when the cartridge plays the record, because the diameter of the tip the stylus of the pickup is finite. The upward crosstalk due to the tracking error is related to the linear one Speed S (cm / sec) of the sound groove of the record, the peak speed amplitude V (cm / sec) of the main channel signal in the tone groove and the radius r (cm) of the spherical surface of the tip of the needle in relation. the The amount of phase modulation of the subchannel signal is given by the following equation expressed by the phase modulation index m, given:

where w is a carrier angular frequency. If the diameter of the tone groove is D (cm) and the number of revolutions per minute is N, it follows that S = - τχ - (cm / sec).

YOU

When the main channel signals with the recording RIAA characteristics are equalized in Fig. 3B and the diameter of the record is constant, the phase modulation index increases m according to the frequency of the main channel signals. The total of these up crosstalk operations is 35 specified. This characteristic curve 35 will stop when the recording speed 11.15 mm / sec and the diameter of the needle 5 u.

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As described above, in the low frequency range, the subchannel signals as signals are influenced by distortion 34 of the demodulated signal in the form of rumbling noise caused by rapid fluctuations in pitch, upward crosstalk 33 due to groove angle error and beat distortion 32 due to crosstalk between the sub-channel signals. In the areas of medium and _high: frequencies, the sub-channel signals from the crosstalk due to the caster 35 and the distortion Clipping distortion 31b are affected due to the limitation of the frequency bandwidth. In the present description, the upstream crosstalk 33 and 35 due to the main channel signals, the beat distortion 32 due to the crosstalk between the subchannel signals, and the clipping distortion 31b due to the limitation of the frequency bandwidth are generally referred to as -cross overmodulation distortion.

This cross-overmodulation distortion is intended to be eliminated by the invention. This is done with the angle modulation of the subchannel signals their modulation curve is chosen so that it is removed from the lines which are responsible for the interference are significant.

The modulation curve is in the low-frequency range from lines 32, 33 and 34. In the ranges of medium and high frequencies, the characteristic curve is preferably chosen so that it is between the characteristic curves 31b and 35 lies. The coincidence of the two main channel signals and the two sub-channel signals in the frequency amplitude characteristic and in the phase characteristic is advantageous for the separation in the case of matrix reproduction of the four signals. Therefore, the boost characteristic for the sub-channel signals, which eventually create a predetermined modulation curve, selected according to the RIAA characteristics in FIGS. 3A and 3B, to thereby spread in the characteristic between

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the main channel signals and the sub-channel signals in the To avoid playback device. In this case one preferably uses a characteristic curve such that the corner point frequency in the low frequency range with respect to the disturbance characteristic 34 by rapid pitch fluctuations something is lifted.

Based on the foregoing explanation, the standard modulation curve for the subchannel signals as selected at 36 in FIG. The standard modulation curve 36 is equal to the RIAA characteristic in Fig. 3A and is in the form of frequency modulation in the range up to 100 Hz the subchannel signal frequency, the form of phase modulation in the range from 100 to 500 Hz, the form of frequency modulation in the range from 500 to 2,100 Hz, the form of phase modulation in the range from 2,100 to 6,000 Hz and the form of frequency modulation in the range above 6,000 Hz.

In addition, since the sub-channel signals TT and TQ in the previous mentioned UM system are as shown in Fig. 2, the difference vector (TT - TQ) is corresponding to the relative Phase deviation of the two sub-channel signals from one another such as shown in FIG. As can be seen from FIG. 7, the relative phase deviation changes with the Position of a sounder so that the way in which the beat distortion is generated is related to the position of the sounder changes.

If the two signals (TT + kTQ) and (TT - kTQ) are chosen as the sub-channel signals, their relative is Phase deviation 2 kTQ. Hence the relative phase deviation evenly distributed in accordance with the location of the sounder. If k <.0.38, the is relative Phase deviation in vector form equal to the vector phasor of signal TQ and smaller in size than that

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Difference (TT - TQ) when the speakers are LF, RF, LB and RB have individual sounders. If k <- ~ -, then 2kTQ less than (TT - TQ) in a wide range of the position of the sounder.

Fig. 8 shows, in the form of a block diagram, an embodiment of the recording device according to that described above Invention. The signals TL, TR, TT and TO of the encoder 2 are applied to a matrix circuit 10 in order to to generate the main channel signals TL and TR and newly formed sub-channel signals (TT + kTQ) and (TT - kTQ). the Main channel signals TL and TR are fed to a mixer circuit 5 via a record equalizer circuit 4. That Sub-channel signal (TT + kTQ) is fed to a phase modulator 6 via a boost circuit 11a and the sub-channel signal (TT - kTQ) is fed to the phase modulator 6 via a boosting circuit 11b. By raising circles 11a and 11b and the phase modulator 6 become the subchannel signals (TT + kTQ) and (TT - kTQ) are angle-modulated in accordance with the modulation curve 36 in FIG. 6. Then the main channel signals and the modulated subchannel signals distributed over two transmission channels and from a 45-45 cutter 8 distributed on the right and left wall of the tone groove.

Fig. 9 shows a further embodiment of the recording device of the invention which is suitable for upward crosstalk due to the tracking distortion in the high frequency range of the subchannel signals.

In this example, two sub-channel signals (TT + kTQ) and (TT-kTQ), which are formed by the matrix circuit 10, are used will. The sub-channel signals (TT + kTQ) and (TT-kTQ) are fed to the boost circuits 11a and 11b, respectively. the Characteristics of the boosting circuits 11a and 11b are predetermined so that the subchannel signal modulation curve is that which is shown at 36 in FIG. 6. This is for

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the suppression of the aforementioned cross modulation distortion.

The sub-channel signals (TT + kTQ) and (TT-kTQ) are fed to adder circuits 12a and 12b, respectively. The adding circles 12a and 12b receive the main channel signals for compensation, which are generated in the following manner. The main channel signals TL and TR are supplied to level control circuits 13a and 13b through the record equalizer 4. The level control circuits 13a and 13b receive a control voltage corresponding to the operation of a raceway of the 45-45 cutter 8th.

The output signals of the level control circuits 13a and 13b become the component of the tracking distortion given by the previous equation m = ■ is expressed.

equalized. The output signals of the level control circuits 13a and 13b are given to inverter circuits 14a and 14b, respectively. The output of the inverter circuit 14a, i.e., the main channel signal for compensation, is of the adding circuit 12a added to the subchannel signal (TT + kTQ) recorded on the same groove wall of the record. On the other hand, the output of the inverter circuit 14b, i. the main channel signal for compensation is added by the adding circuit 12b to the subchannel signal which is on the same groove wall is recorded.

The sub-channel signals (TT + kTQ) ¹ and (TT-kTQ) ¹ , which in this way have counter-compensated for an expected tracking distortion, are fed to the phase modulator 6. The modulated sub-channel signals (TT + kTQ) "and (TT - kTQ)" of the phase modulator 6 are added to the main channel signals in the mixer circuit 5 to produce two signals (TL + (TT + kTQ) ") and (TR + (TT - kTQ ) "), which are fed via an amplifier 7 to the 45-45 cutting device 8 and recorded by this on the right or left wall of the sound groove.

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Since in the invention the subchannel signals according to the expected tracking distortion during the record cutting are compensated in the opposite direction, it is possible to prevent upward crosstalk during playback to avoid. If an error in the diameter of the tip of the needle is within 10%, upward cross-talk may occur due to tracking distortion due to phase modulation with opposite phase to the angle modulator of the recording system can be reduced by 2OdB.

It is necessary that the main channel signals supplied to the level control circuits 13a and 13b for forming the compensation main channel signals be the same as those which will ultimately be recorded on the walls of the sound groove. In order to ensure equality, it is also possible to supply the main channel signals to the level control circuits 13a and 13b via equalizers or similar devices.

It has also already been described that when the sub-channel signals (TT + kTQ) and (TT - kTQ) are used, the beat distortion caused by the signal TQ of the component reverse phase is generated between the sub-channel signals. When the signal TQ decreases in the frequency range or removed in which the relative phase deviation increases and the beat distortion is likely to occur, the beat distortion can be further reduced.

Fig. 10 shows, in block diagram form, another embodiment of the recording device of the invention; which is constructed in view of the above.

Of the signals TL, TR, TT and TQ which the encoder 2 emits, the signal TQ is sent to the matrix circuit 10 via a high-pass filter 12 supplied. Since the high-pass filter 15 here has a phase characteristic, phase equalizers 16a, 16b are used

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and 16c are provided for the other signals T1, TR and TT, so that an excellent phase relationship is maintained will. The frequency spectra of the signals TL, TR, TT and TQ, which are fed to the matrix circuit 10, are therefore as follows: as shown in FIG. 11. The signals TL and TR all have band frequency components necessary to reproduce a Sound field are necessary, and the signals TT and TQ have minimum necessary frequency components and the signal TQ is cut off at low frequencies. Even if the low frequency components of the signal TQ are cut off this affects psychoacoustically related with the definition of the parts of low and high pitch is not enough, and only with the signals TL, TR and TT it is possible to use a 4-channel stereo effect with handy sufficient separation to be expected.

The recording device in Fig. 10 is for use not only in the UM system or the discrete 4-channel stereo system, but also suitable if the so-called matrix system has the 4-channel effect, with only the Main channel signals can be changed by adding two sub-channel signals.

Instead of the filter to remove the low frequency range of the signal TQ in which the beat distortion is likely to occur, a limiter 17 can be provided which limits the level of the signal TQ when it Signal reaches a certain level, i.e. becomes so large that it causes the beat distortion, as shown in Fig. is shown. The limiter 12 does not completely cut off the low frequency range of the signal TQ, so that it is possible is to substantially completely prevent the effects such as the sense of presence, the location of the sounder, etc. from being impaired will.

The gramophone record that came with the recording device of the invention is produced as described in the previously

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written Fig. 8 or 9 is shown, and the record, which is manufactured with the recording device as shown in Fig. 10 or 12, and the the high-pass filter and phase equalizers 16a, 16b and 16c or the limiter 17 can be used by an in 13 can be reproduced.

In Fig. 13, the modulated subchannel signals, which are separated by a band-pass filter 15 from a reproduced signal picked up by a pickup 21, are supplied to a frequency demodulator 26. The demodulated output signals of the frequency demodulator 26 are fed to a matrix circuit 28 via de-equalization circuits 27a and 27b, the properties of which are opposite to those of the emphasis circuits 11a and 11b of the recording device. The matrix circuit 28 outputs the sub-channel signals TT and TQ to a decoder 2 4 together with the main channel signals TL and TR. The decoder 24 outputs audio signals S _T _, S _n -, S__ and S _m according to sound

Jjr Kc Jjö Kb

donors _# special arrangement, and these signals are amplified and fed to the loudspeakers LF, RF _f LB and RB.

When the signal TQ is supplied to the matrix circuit 10, it is supplied through an equalizing circuit 18 as shown in FIG. This equalizer circuit 18 has a frequency characteristic 40 as shown in FIG. If the signal TQ is passed through the equalization circuit 15, the changes Modulation curve for the subchannel signals (TT + kTQ) and (TT - kTQ) from line 38 to line 39 in FIG. 16. Thus the area exceeding the line 32 becomes indicative of the limit of generation of beat distortion is, a low frequency area and the beat distortion can be decreased.

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Instead of using the equalizer 18, the same effect can also be achieved in that the boosting circles 11a and 11b have different characteristics.

When playing the vinyl record with the recording device in FIG. 14, the signal TQ of the matrix circuit 28 is sent to an equalization circuit 29 whose characteristic is opposite to that in Fig. 15, and the signal TQ can from the equalizing circuit 29, which is fed to a decoder 24 shown in FIG.

The encoder 2 and the matrix circle 10 in that described above The recording device can in practice be constructed in the form of a single matrix circle. The same applies to the decoder 24 and the matrix circle in the display device. The foregoing description has mainly been made with reference to the recording device, It goes without saying, however, that the enhancement characteristics of the sub-channel signals in the reproduction device can be selected in the same way according to the playback RIAA characteristics of the main channel signals.

As the boost characteristics for modulating the sub-channel signals based on the particular modulation curve 36 corresponding to the recording RIAA characteristics of the main channel signals are selected, the main channel signals and the sub-channel signals agree with one another in the frequency amplitude characteristic and match in phase characteristic, and excellent separation can be achieved. In addition, the subchannel signals are matched by the matrix circle in such a way that the components are in phase between the subchannel signals is increased and the opposite phase component is decreased. It is therefore possible to use the Eliminate beat distortion that affects the crosstalk

between the modulated subchannel signals and caused by the opposite phase component will. In addition, when sub-channel signals are changed in the above-mentioned manner, the stereophonic effect becomes does not deteriorate during playback.

The invention is of equal utility when used not only in the UM system, but also in the so-called '. CD-4 system, etc. The invention is also useful not only in the use of a phonograph record as a recording medium, but can also be used when using a multi-track magnetic tape.

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Claims (12)

Expectations Device for recording multi-channel audio signals on a recording medium, characterized by a Signal source for the delivery of four separate channel signals, a coding circuit for a first and second main channel signal and a first and second sub-channel signal the four separate channel signals, an oscillator for generating a carrier signal with a predetermined Frequency, a modulator for angle modulation of the carrier signal together with the first and second sub-channel signal, a mixer responsive to the first and second main channel signals and the output signal of the modulator, a device for the simultaneous recording of the sum signal of the first main channel signal and the first sub-channel signal and 'the sum signal of the second main channel signal and the second sub-channel signal, and an emphasis circuit connected to the input signal transmission path of the angle modulator is connected and has boost characteristics that are substantially with predetermined Match the recording equalization characteristics with respect to the main channel signals. 2. Device for recording multi-channel audio signals on a recording medium, characterized by a signal source for the output of four separate channel signals, a coding circuit for a first and second main channel signal and a first and second sub-channel signal the four separate channel signals, an oscillator for generating a carrier signal with a predetermined Frequency, a modulator for angle modulation of the carrier signal together with the first and second sub-channel signals, a mixer that acts on the first and second main channel signals and the output of the modulator is responsive to means for simultaneous recording the sum signal of the first main channel signal and the first sub-channel signal and the sum signal of the two 409848/0846 th main channel signal and the second sub-channel signal, and a matrix circuit for generating a sum signal and a difference signal of the first subchannel signal and a portion of the second subchannel signal. 3. Device according to claim 2, characterized in that the transmission characteristic curve of the signal transmission path for the Sunun signal from that of the signal transmission path is different for the difference signal. 4. Device according to claim 3, characterized in that a first boosting circuit in the sum signal transmission path is arranged having predetermined characteristics, and that a second boost circuit in the differential signal transmission path which has characteristics different from those of the first boosting circle. 5. Device according to claim 3, characterized in that the differential signal transmission path is a high pass filter. 6. Device according to claim 3, characterized in that the difference signal transmission path is an amplitude delimiter is. 7. Device for recording multi-channel audio signals on a recording medium, characterized by a signal source for the delivery of four separate channel signals, a coding circuit for a first and second main channel signal and a first and second sub-channel signal the four separate channel signals, an oscillator for generating a carrier signal with a predetermined Frequency, a modulator for angularly modulating the carrier signal along with the first and second sub-channel signals, a mixer responsive to the first and second main channel signals and the output signal of the modulator, a device for simultaneous recording 409848/0846 the suirane signal of the first main channel signal and the first sub-channel signal and the suirane signal of the second main channel signal and the second sub-channel signal, and in that the transmission path of the second subchannel signal is an equalization circuit with a predetermined characteristic. - 8. device for recording multichannel tonsianals, characterized by a signal generator for generating a control signal corresponding to the radius of a spiral Recording groove, first and second level control devices for controlling the level of the first and second main channel signals with the control signal, a Phase inverter for reversing the phase of the first and second main channel signals, a first adding circuit for generating a sum signal of the first sub-channel signal and the first main channel signal that is reversed in phase and is controlled in level, and a second adding circuit for generating a sum signal of the second sub-channel signal and the second main channel signal. 9. Recording medium on which a signal with a device according to any one of claims 1 to 8 is recorded. 10. Device for reproducing multichannel audio signals which are recorded on a recording medium with a device according to one of claims 1 to 7, characterized by a pickup for generating electrical Signals depending on the signals recorded on the medium, a separator for separating the first and second main channel signals and the first and second carrier channel signals, a demodulator for angle demodulation of the first and second carrier channel signals, a decoding circuit which is based on the separated first and second main channel signal and the demodulated first and 409848/0846 second subchannel signal is responsive to reproduce the original four channel signals, means comprising four loudspeakers for sound generation depending on the reproduced four channel signals, and a reduction circuit connected to the output signal transmission path of the angle demodulator and attenuation characteristics which has substantially the predetermined reproduction equalization characteristics with respect to the main channel signals to match. 11. Device for reproducing multichannel audio signals recorded on a recording medium with a device according to one of claims 1 to 7, characterized by a pickup for generating electrical signals as a function of the signals recorded on the medium, a separating device for Separating the first and second main channel signals and the first and second carrier channel signals, a demodulator for angle demodulating the first and second carrier channel signals, a decoding circuit responsive to the separated first and second main channel signals and the demodulated first and second subchannel signals to reproduce the original four channel signals, a device with four loudspeakers for generating sound in accordance with the reproduced four channel signals, and a matrix circuit for separating the original first and second sub-channel signals from the sum and difference signals of the first and second sub-channels lsignals. 12. Device for reproducing multichannel audio signals which are recorded on a recording medium with a device according to one of claims 1 to 7 were recorded, characterized by e ^ NEN pickup for generating electrical Signals depending on the signals recorded on the medium, a separator for separating the first and second main channel signal and the first and second carrier channel signal, a demodulator for angular 409848/0846 demodulation of the first and second carrier channel signals, a decoding circuit based on the separated first and second main channel signal and the deriodulated first and second subchannel signals respond to the original to reproduce four channel signals, a device with four loudspeakers for sound generation in dependence on the reproduced four channel signals, and a reproduction equalization circuit with a predetermined characteristic, which is connected to the transmission path of the second sub-channel signal. 409848/0846