GB1347994A - Sound recording and reproduction - Google Patents

Sound recording and reproduction

Info

Publication number
GB1347994A
GB1347994A GB1948871A GB1948871A GB1347994A GB 1347994 A GB1347994 A GB 1347994A GB 1948871 A GB1948871 A GB 1948871A GB 1948871 A GB1948871 A GB 1948871A GB 1347994 A GB1347994 A GB 1347994A
Authority
GB
Grant status
Application
Patent type
Prior art keywords
signals
channels
signal
channel
gain
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB1948871A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CBS Broadcasting Inc
Original Assignee
CBS Broadcasting Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04SSTEREOPHONIC SYSTEMS 
    • H04S3/00Systems employing more than two channels, e.g. quadraphonic
    • H04S3/02Systems employing more than two channels, e.g. quadraphonic of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other

Abstract

1347994 Four channel stereophonic systems COLUMBIA BROADCASTING SYSTEM Inc 8 June 1971 [8 June 1970] 19488/71 Heading H4R In an apparatus for deriving from first and second composite signals four signals for reproducing on four loud-speakers, four separate channels of programme information, and in which each composite signal contains component signals representing respective ones of two of the channels together with, in each composite signal, in-phase portions of a third channel and phase-displaced portions of a fourth channel, the composite signals are appropriately combined to derive a first set of signals each containing a major portion of the signal in respective ones of the four channels of information, together with signals in the two adjacent ones of the four channels of information. The four signals are fed to the reproducing circuits via amplifiers whose gain is controlled by a circuit which determines which channel contains the predominant signal and increases the gain of the amplifier in the corresponding channel relative the gains of the amplifiers in the other channels. The four channels can be controlled independently or controlled in pairs, each pair comprising the channels feeding opposed signals. Fig. 7 shows one embodiment in which the two composite signals from amplifiers 40 and 42 are fed directly to respective gain controlled amplifiers 96 and 102 to provide signals for the left L and right R speakers while the sum and difference of the two composite signals are fed to respective gain controlled amplifiers 98 and 100 to provide signals for the front C and back D loud-speakers. The composite signals are also fed via equalizers 59 and 61, having inverse equal loudness characteristics, to gain controlled amplifiers 58 and 60 the output from which are fed to a matrix circuit to derive the four output channels. The signals in the four channels are rectified by rectifiers 68 to 74 to derive control signals for the gain controlled amplifiers 96, 98, 100, 102 in the main channels. The four control signals are also combined on -resistor 84 to provide a control signal for the gain of amplifiers 58 and 60 which tend to stabilize the combined signal on resistor 84 so that the individual signals, e l , e c , e d , e r are held to a specific rate. Each control signal has a bias 104, 106, 108, 110 added to it and the arrangement is such that a signal present in the right channel R tends to cut off the amplifier handling the left L signal and vice versa, and a signal in the C channel cuts off the amplifier handling the D signal, and vice versa. In one alternative arrangement, Fig. 9 (not shown), the four gain control signals are applied to each gain control amplifier via weighting networks, which weight control in favour of the signal level in the diagonally opposed channel, while in a second alternative system, Fig. 11 (not shown), the signal level in the left and right channels is compared with that in the front and rear channels and the gains of those pairs of channels controlled inversely.
GB1948871A 1970-06-08 1971-06-08 Sound recording and reproduction Expired GB1347994A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US4419670 true 1970-06-08 1970-06-08

Publications (1)

Publication Number Publication Date
GB1347994A true true GB1347994A (en) 1974-02-27

Family

ID=21931011

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1948871A Expired GB1347994A (en) 1970-06-08 1971-06-08 Sound recording and reproduction

Country Status (8)

Country Link
US (1) US3708631A (en)
JP (1) JPS5017843B1 (en)
BE (1) BE768184A (en)
CA (1) CA961417A (en)
DE (1) DE2126480B2 (en)
FR (1) FR2094122B1 (en)
GB (1) GB1347994A (en)
NL (1) NL7106252A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2514598A (en) * 2013-05-30 2014-12-03 Egils Ranga An optimised three speaker stereo sound system

Families Citing this family (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3787622A (en) * 1971-02-05 1974-01-22 Sansui Electric Co Quadrasonic sound system for two channel transmission
US3784744A (en) * 1971-02-24 1974-01-08 Columbia Broadcasting Syst Inc Decoders for quadruphonic sound utilizing wave matching logic
US3967063A (en) * 1971-06-23 1976-06-29 Cbs Inc. Logic for matrix systems for reproducing quadraphonic sound
US3830978A (en) * 1971-07-08 1974-08-20 Matsushita Electric Ind Co Ltd Circuit for mixing four audio input signals to produce four audio output signals
JPS5213082B1 (en) * 1971-07-19 1977-04-12
GB1398786A (en) * 1971-08-06 1975-06-25 Sony Corp Multisignal transmission apparatus
US3794781A (en) * 1971-09-01 1974-02-26 Columbia Broadcasting Syst Inc Four channel decoder with improved gain control
US3824618A (en) * 1971-10-07 1974-07-16 Pioneer Electronic Corp Magnetic head and simulated four-channel stereo system
US3772479A (en) * 1971-10-19 1973-11-13 Motorola Inc Gain modified multi-channel audio system
US3783192A (en) * 1971-12-30 1974-01-01 Sansui Electric Co Decoder for use in matrix four-channel system
JPS5240563B2 (en) * 1972-03-07 1977-10-13
JPS5228361B2 (en) * 1972-03-09 1977-07-26
JPS5317283B2 (en) * 1973-03-07 1978-06-07
GB1522599A (en) * 1974-11-16 1978-08-23 Dolby Laboratories Inc Centre channel derivation for stereophonic cinema sound
US4018992A (en) * 1975-09-25 1977-04-19 Clifford H. Moulton Decoder for quadraphonic playback
US4006306A (en) * 1975-10-10 1977-02-01 Yudin Industries, Inc. Audio signal processing apparatus
US4474441A (en) * 1980-03-04 1984-10-02 Polaroid Corporation Method and apparatus for controlling exposure by selective use of blocking visible filter
US4532647A (en) * 1981-08-19 1985-07-30 John C. Bogue Automatic dimension control for a directional enhancement system
US4525855A (en) * 1981-08-27 1985-06-25 John C. Bogue Variable rate and variable limit dimension controls for a directional enhancement system
US4799260A (en) * 1985-03-07 1989-01-17 Dolby Laboratories Licensing Corporation Variable matrix decoder
US5046098A (en) * 1985-03-07 1991-09-03 Dolby Laboratories Licensing Corporation Variable matrix decoder with three output channels
US5339363A (en) * 1990-06-08 1994-08-16 Fosgate James W Apparatus for enhancing monophonic audio signals using phase shifters
US5172415A (en) * 1990-06-08 1992-12-15 Fosgate James W Surround processor
US5504819A (en) * 1990-06-08 1996-04-02 Harman International Industries, Inc. Surround sound processor with improved control voltage generator
US5666424A (en) * 1990-06-08 1997-09-09 Harman International Industries, Inc. Six-axis surround sound processor with automatic balancing and calibration
US5295189A (en) * 1990-06-08 1994-03-15 Fosgate James W Control voltage generator for surround sound processor
US6925426B1 (en) 2000-02-22 2005-08-02 Board Of Trustees Operating Michigan State University Process for high fidelity sound recording and reproduction of musical sound
US20170078793A1 (en) * 2015-03-23 2017-03-16 Eric Jay Alexander Inversion Speaker and Headphone for Music Production

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2098561A (en) * 1934-02-09 1937-11-09 Rca Corp System for producing stereosonic effects
US2126929A (en) * 1936-05-15 1938-08-16 Bell Telephone Labor Inc Sound reproducing system
US3184550A (en) * 1961-06-06 1965-05-18 Admiral Corp Stereophonic system with derived center channel
US3632886A (en) * 1969-12-29 1972-01-04 Peter Scheiber Quadrasonic sound system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2514598A (en) * 2013-05-30 2014-12-03 Egils Ranga An optimised three speaker stereo sound system
GB2514598B (en) * 2013-05-30 2015-04-29 Egils Ranga An optimised three speaker stereo sound system

Also Published As

Publication number Publication date Type
US3708631A (en) 1973-01-02 grant
FR2094122A1 (en) 1972-02-04 application
DE2126480B2 (en) 1976-09-30 application
CA961417A1 (en) grant
FR2094122B1 (en) 1976-12-03 grant
NL7106252A (en) 1971-12-10 application
BE768184A1 (en) grant
BE768184A (en) 1971-12-07 grant
CA961417A (en) 1975-01-21 grant
JPS5017843B1 (en) 1975-06-24 grant
DE2126480A1 (en) 1972-01-27 application

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Legal Events

Date Code Title Description
49S Specification amended (sect. 9/1949)
PS Patent sealed
49S Specification amended (sect. 9/1949)
PCNP Patent ceased through non-payment of renewal fee