WO1999026455A1 - Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround - Google Patents

Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround Download PDF

Info

Publication number
WO1999026455A1
WO1999026455A1 PCT/CA1997/000882 CA9700882W WO9926455A1 WO 1999026455 A1 WO1999026455 A1 WO 1999026455A1 CA 9700882 W CA9700882 W CA 9700882W WO 9926455 A1 WO9926455 A1 WO 9926455A1
Authority
WO
WIPO (PCT)
Prior art keywords
channel signal
signal
stereophonic
decoding
decoding circuit
Prior art date
Application number
PCT/CA1997/000882
Other languages
English (en)
Inventor
Martin Pineau
Original Assignee
Xd Lab R & D 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
Application filed by Xd Lab R & D Inc. filed Critical Xd Lab R & D Inc.
Priority to CA002308576A priority Critical patent/CA2308576A1/fr
Priority to ES97913055T priority patent/ES2176716T3/es
Priority to AT97913055T priority patent/ATE218267T1/de
Priority to EP97913055A priority patent/EP1064824B1/fr
Priority to PCT/CA1997/000882 priority patent/WO1999026455A1/fr
Priority to DE69712926T priority patent/DE69712926T2/de
Priority to DK97913055T priority patent/DK1064824T3/da
Priority to AU50453/98A priority patent/AU748414B2/en
Priority to JP2000521683A priority patent/JP2001523937A/ja
Publication of WO1999026455A1 publication Critical patent/WO1999026455A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic

Definitions

  • the present invention relates to stereophonic surround sound decoding circuits More specifically, the present invention relates to a post- amplification stereophonic to surround sound decoding circuit to be installed between the outputs of a conventional stereophonic amplifier and conventional loudspeakers.
  • Stereophonic sound systems aim at reproducing two different sound channels, via loudspeakers, in such a way that the sounds reaching each ear of the listener give the impression to the listener that he is brought at the location of the sound recording.
  • the realism of this impression depends on many factors such as, for example, the relative position of the listener with respect to the loudspeakers and the quality of the recording.
  • surround sound decoding circuits used in surround sound systems may generally be divided into two major types, i.e., pre-ampiification decoding circuits and post-amplification decoding circuits.
  • Surround sound systems using pre-ampiification decoders receive a conventional low level two-channel stereophonic sound signal and expend it to a five-channel surround sound. Each of these five channels is amplified separately and then supplied to a predetermined loudspeaker.
  • the five channels are generally determined as follows: a main left channel corresponds to the left channel of the stereophonic sound signal and is reproduced by a front left loudspeaker; a main right channel corresponds to the right channel of the stereophonic sound signal and is reproduced by a front right loudspeaker; a secondary left channel (also called the left surround channel) is decoded by subtracting the main right channel from the main left channel and is reproduced by a rear left loudspeaker; a secondary right channel (also called the right surround channel) is decoded by subtracting the main left channel from the main right channel and is reproduced by a rear right loudspeaker; and a central channel is decoded by adding the main left channel and the main right channel, and is reproduced by a central loudspeaker usually mounted on top of the television screen.
  • a main left channel corresponds to the left channel of the stereophonic sound signal and is reproduced by a front left loudspeaker
  • a main right channel corresponds to the right channel of the stereophonic sound signal
  • a major drawback of the surround sound systems using pre- amplification decoders is that a five-channel amplifier is necessary to reproduce the surround sound since the power amplification is done after the decoding of the surround sound from the stereophonic sound. Users of this technology must therefore acquire a dedicated power amplifier, which increases the total cost of the system.
  • Post-amplification surround sound decoders usually solve the above-mentioned drawback of the pre-ampiification decoders by providing an apparatus that may be installed between the left and right power amplified stereophonic signal outputs of a conventional stereophonic amplifier and the five loudspeakers mentioned hereinabove.
  • the stereophonic to surround sound decoding is therefore done after the power amplification which allows the use of a conventional stereophonic amplifier.
  • the return to the ground of the negative terminal of the central loudspeaker via an inductance will also increase the complexity of the load of the power amplifier wich will inevitably lead to an increase in sound distortion and an overall general decrease in the sound reproduction.
  • the combination, via resistors, of the right and left channels to generate the central channel will decrease the clarity of the sound reproduction of the main right and left channels since there are no provisions to prevent some "bleeding" of the right channel in the left channel and vice-versa.
  • Robert J. Rapoport and entitled: "MULTI-CHANNEL SURROUND SOUND SIMULATION DEVICE", describes a hybrid stereophonic to surround sound decoder provided with features from both the pre-ampiification and post- amplification decoding schemes described hereinabove.
  • the system proposed by Rapoport has many drawbacks. For example, a supplementary power amplifier must be provided to amplify the central channel before the reproduction by the central loudspeaker.
  • the drawbacks discussed hereinabove with respect to the system of Madnick et al. generally apply to the system of Rapoport since the design philosophy is similar.
  • An object of the present invention is therefore to provide an improved post-amplification stereophonic to surround sound decoding apparatus free of the above-mentioned drawbacks of the prior art.
  • a post-amplification stereophonic to surround sound decoding circuit comprising: an input for receiving a power amplified stereophonic signal including a left channel signal and a right channel signal; a first output configured to be connected to a secondary left loudspeaker; a second output configured to be connected to a secondary right loudspeaker; a third output configured to be connected to a central loudspeaker; secondary channels decoding means for decoding a secondary left channel signal and a secondary right channel signal from the left and right channel signals of the power amplified stereophonic signal; the secondary left channel signal being supplied to the first output and the secondary right channel signal being supplied to the second output; and central channel decoding means for decoding a central channel signal from the left and right channel signals of the power amplified stereophonic signal; the central channel decoding means including first and second decoupling means respectively decoupling the left and right channel signals; the central channel decoding means including means for combining the left and right decoupled channel signals into the central
  • a post-amplification stereophonic to surround sound decoding circuit comprising: an input for receiving a power amplified stereophonic signal including a left channel signal and a right channel signal; a first output configured to be connected to a secondary left loudspeaker; a second output configured to be connected to a secondary right loudspeaker; a third output configured to be connected to a central loudspeaker; a fourth output configured to be connected to a main left loudspeaker; a fifth output configured to be connected to a main right loudspeaker; secondary channels decoding means for decoding a secondary left channel signal and a secondary right channel signal from the left and right channel signals of the power amplified stereophonic signal; the secondary left channel signal being supplied to the first output and the secondary right channel signal being supplied to the second output; central channel decoding means for decoding a central channel signal from the left and right channel signals of the power amplified stereophonic signal; the central channel decoding means including first and second decoupling means respectively
  • a central channel decoding circuit for a post-amplification stereophonic to surround sound decoding apparatus comprising: an input for receiving a power amplified stereophonic signal including a left channel signal and a right channel signal; an output configured to be connected to a central loudspeaker; and central channel decoding means for decoding a central channel signal from the left and right channel signals of the power amplified stereophonic signal; the central channel decoding means including first and second decoupling means respectively decoupling the left and right channel signals; the central channel decoding means including means for combining the left and right decoupled channel signals into the central channel signal; the central channel signal being supplied to the output; whereby the decoupling means of the central channel decoding means allow the left and right channel signals of the power amplified stereophonic signal to be combined without modifying the original left and right channel signals.
  • Figure 1 illustrates, in a block diagram, a post-amplification stereophonic to surround sound decoding circuit according to an embodiment of the present invention; the decoding circuit being connected to a stereophonic power amplifier and to five loudspeakers;
  • Figure 2 illustrates, in a schematic view, the post-amplification stereophonic to surround sound decoding circuit of figure 1 ;
  • Figure 3 illustrates, in a schematic view, an alternate embodiment of the central channel decoding circuit illustrated in figure 2.
  • the decoding circuit 10 illustrated in figure 1 is shown connected to a stereophonic power amplifier 12.
  • the decoding circuit 10 includes a left input 14, a right input 16 and a ground connection 18 respectively connected to a left output 20, a right output 22 and a ground connection 24 of the stereophonic power amplifier 12.
  • the connections 20, 22 and 24 of the power amplifier 12 are usually connected to two conventional main left and main right loudspeakers.
  • the decoding circuit 10 also includes a two terminal main left loudspeaker output 26, 27 connected to a main left loudspeaker 28, a two terminal main right loudspeaker output 30, 31 connected to a main right loudspeaker 32, a two terminal secondary left loudspeaker output 34, 35 connected to a secondary left loudspeaker 36, a two terminal secondary right loudspeaker output 38, 39 connected to a secondary right loudspeaker 40 and a two terminal central loudspeaker output 42, 43 connected to a central loudspeaker 44.
  • the decoding circuit 10 includes a main channels volume control circuit 46, a secondary channels decoding circuit 48 and a central channel decoding circuit 50.
  • the main channels volume control circuit 46 interconnects the inputs 14, 16 and 18 and the main loudspeakers outputs 26, 27, 30 and 31; the secondary channels decoding circuit 48 interconnects the inputs 14 and 16 and the secondary loudspeakers outputs 34, 35, 38 and 39; and the central channel decoding circuit 50 interconnects the inputs 14, 16 and 18 and the central loudspeaker outputs 42 and 43.
  • the main channels volume control circuit 46 includes a variable resistor 52 connected to the left input 14 and to the output 26 to the main left loudspeaker and a variable resistor 54 connected to the right input 16 and to the output 30 to the main right loudspeaker.
  • a variable resistor 52 connected to the left input 14 and to the output 26 to the main left loudspeaker
  • a variable resistor 54 connected to the right input 16 and to the output 30 to the main right loudspeaker.
  • variable resistors 52 and 54 could be advantageously embodied together in a stereophonic L-pad (with no ground connection) and having an appropriate power rating. If this is the case, the user will be faced with only one volume control for the two main loudspeakers.
  • the variable resistors could also be embodied by a plurality of discrete high quality resistors (not shown) and switches (not shown) or by a high power levels variable resistance integrated circuit (not shown).
  • variable resistor is to be construed, herein and in the appended claims, as any electronic element or arrangement of resistive and/or other electronic elements allowing the modification of a resistance between two points of an electrical circuit.
  • the secondary channels decoding circuit 48 includes a first capacitor 56 connected to the left input 14 and to the output 34 to the secondary left loudspeaker, a second capacitor 58 connected to the right input 16 and to the output 38 to the secondary right loudspeaker and a variable resistor 60 connected to the ground output connection 35 to the secondary left loudspeaker and to the output ground connection 39 to the secondary right loudspeaker. It is to be noted that the ground output connections 35 and 39 are not connected to the input ground connection 18.
  • the connection of the variable resistor 60 between the output ground connections 35 and 39 causes the secondary loudspeakers to reproduce respective secondary channel signals that are obtained by a substraction of the signal supplied to the inputs 14 and 16. More specifically, the secondary left channel signal reproduced by the secondary left loudspeaker is the signal supplied to the left input 14 minus the signal supplied to the right input 16. Similarly, the secondary right channel signal reproduced by the secondary right loudspeaker is the signal supplied to the right input 16 minus the signal supplied to the right input 14. Since the secondary channels decoding circuit 48 is not connected to the ground, the secondary left and right channel signals are equal since the subtraction of the input 14 from the input 16 is equal to the subtraction of the input 16 from the input 14.
  • capacitors 56 and 58 are, in a sense, decoupling capacitors and since the secondary channels decoding circuit 48 is not connected to the ground, the interconnection of the ground connections 35 and 39 will have no ill effect on the signals supplied to the main channels volume control circuit 46 and to the central channel decoding circuit 50 since the capacitors 56 and 58 prevent the signal supplied to the input 14 to "bleed" in the signal supplied to the input 16 and vice-versa.
  • resistor 60 By varying the value of the resistor 60, one modifies the amplitude of the signal supplied to the secondary loudspeakers, thus varying the volume of the sound reproduced by the secondary loudspeakers, since the portion of the power amplified signal dissipated as heat in the resistors is modified.
  • the central channel decoding circuit 50 includes a first fixed value resistor 62 connected to the left input 14, a first capacitor 64 connected to the first resistor 62, a second fixed value resistor 66 connected to the right input 16, a second capacitor 68 connected to the second resistor 66 and a variable resistor 70 interconnecting both capacitors 64 and 68 to the output 42 to the central loudspeaker.
  • the ground connection 43 is connected to the ground input connection 18.
  • the signal supplied to the central loudspeaker output 42 is therefore the addition of the signal supplied to the left and right inputs 14 and 16 by the power amplifier 12.
  • capacitors 64 and 68 are, in a sense, decoupling capacitors, the interconnection of the output of these capacitors to cause the addition of the left and right inputs 14 and 16 will have no ill effect on the signals supplied to the main channels volume control circuit
  • resistor 70 modifies the amplitude of the signal supplied to the central loudspeaker, thus varying the volume of the sound reproduced by the central loudspeakers, since the portion of the power amplified signal dissipated as heat in the resistor is modified.
  • variable resistors 60 and 70 could be advantageously embodied in separate monophonic L-pads (with no ground connections) and having an appropriate power ratings.
  • the variable resistors 60 and 70 could also be embodied by a plurality of discrete high quality resistors (not shown) and switches (not shown) or by high power levels variable resistance integrated circuits (not shown).
  • variable resistor 70 provided downstream from the interconnection of the left and right inputs by a pair of variable resistors 170, 170" respectively provided between the fixed value resistors 62, 66 and the capacitors 64, 68, thus upstream from the interconnection of the left and right inputs.
  • the decoding circuit 150 improves the impedance and frequency stability as well as allowing more usable power to be supplied to the central loudspeaker.
  • variable resistors 170 and 170' could be advantageously embodied together in a stereophonic L-pad (with no ground connection) and having an appropriate power rating.
  • the variable resistors could also be embodied by a plurality of discrete high quality resistors (not shown) and switches (not shown) or by a high power levels variable resistance integrated circuit (not shown).
  • the impedance of the post-amplification stereophonic to surround sound decoding circuit 10 "seen" by the outputs 20, 22 and 24 of the power amplifier 12 is essentially similar to the impedance of the main loudspeakers since the decoding circuits 48 and 50 use decoupling capacitors and are therefore virtually “invisible” as far as impedance is concerned. Indeed, the impedances of the decoding circuits 48 and 50 are so much higher than the impedance of the main loudspeakers 28 and 32 that the connection of the circuits 48 and 50, generally in parallel, therewith will not modify significantly the impedance seen by the outputs 20, 22 and 24 of the power amplifier.
  • fuses 72, 74 and 76 are provided between the inputs 14, 16 and 18 and the circuits 46, 48 and 50 as protection. It is also to be noted that an on/off switch (not shown) could advantageously be provided to disconnect the circuits 48 and 50 from the inputs 14, 16 and 18 when the user wants to use only the main loudspeakers and does not want to hear a surround sound.
  • circuits 46, 48 and 50 have been described as separate circuits, these circuits may advantageously be embodied together onto a printed circuit board (not shown).
  • each circuit includes volume controls accessible to the user to modify the voiume of each of the three groups of loudspeakers, i.e., the main loudspeakers, the secondary loudspeakers and the central loudspeaker. Indeed, it has been found that some users prefer to hear the surround channels (reproduced by the secondary loudspeakers) and the central channel (reproduced by the central loudspeaker) at a greater or lesser volume than is considered optimal.
  • the decoding circuit 10 may be connected to a number of different stereophonic power amplifiers and to a number of different loudspeakers, the separate volume controls help compensate for these differences.
  • a simpler and less expensive post-amplification stereophonic to surround sound decoding circuit could be done by removing the variable resistors 52, 54, 60 and 70 (or, alternatively 170, 170').
  • the fuses 72, 74 and 76 could be removed from the circuit since they are provided only for overload protection. It will be noted that such a simplified circuit (not shown) would be less versatile since the user would have no independent control on the three groups of loudspeakers.
  • the post-amplification stereophonic to surround sound decoding circuit 10 described hereinabove includes outputs to the main left and main right loudspeakers, it would be within the skills of one knowledgeable in the art to design a decoding apparatus (not shown) not including these outputs if the decoder was intended to be used with a power amplifier provided with two pairs of left-right outputs. Indeed, one pair of outputs could be directly connected to the main left and main right loudspeakers, while the other pair of outputs could be supplied to the decoding apparatus to yield the secondary left, secondary right and central outputs as described hereinabove.
  • the post-amplification stereophonic to surround sound decoding circuit 10 may advantageously be packaged in an enclosure provided with adequate connectors for the input and outputs of the circuit 10 to yield a post-amplification stereophonic to surround sound decoding apparatus.
  • the actuators of the variable resistors 52, 54, 60 and 70 are advantageously positioned so as to be accessible to the user.
  • the decoding circuit 10 could be installed in a conventional power amplifier to yield a surround power amplifier without requiring five amplification channels.
  • the post-amplification stereophonic to surround sound decoding circuit of the present invention has many advantage over the stereophonic to surround sound of the prior art, such as: the decoding is done downstream from the power amplification, allowing the user to keep his conventional stereophonic power amplifier; the decoding circuit is compatible with every conventional consumer and professional loudspeaker; the decoding circuit is compatible with every conventional consumer and professional audio power amplifier; the decoding circuit allows the user to control his listening experience by independently varying the volume of the three groups of loudspeakers; the decoding is compatible with every known two channels mixed encoding standards such as, for example, the home theater surround sound developed by Dolby laboratories, the Pro-LogicTM technique and the THXTM technique developed by Lucas Arts Entertainment Co.; the decoding circuit does not require an additional power source; the decoding circuit offers a wide bandwidth to the center and surround channels; the decoding circuit may easily be designed to allow unusual and complex loudspeaker impedance load; the decoding circuit may easily be designed to handle high power signals by providing
  • the decoding circuit may easily be designed with a computer- controlled interface, to control the separate volumes, for example, if the particular decoding circuit is intended to be used by a computer controlled application.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Stereophonic System (AREA)
  • Amplifiers (AREA)

Abstract

Cette invention concerne un circuit de post-amplification permettant de décoder un son depuis un mode stéréophonique en un mode surround. Ce circuit de décodage possède des entrées qui sont connectées à un amplificateur de puissance stéréophonique de manière à recevoir un signal stéréophonique amplifié en puissance, ainsi que des sorties qui sont connectées à des haut-parleurs droit et gauche principaux, à des haut-parleurs droit et gauche secondaires et à un haut-parleur central. Le circuit de décodage comprend également un circuit de décodage de canaux secondaires qui va décoder les signaux de canaux surround gauche et droit devant être envoyés respectivement aux haut-parleurs gauche et droit secondaires, ainsi qu'un circuit de décodage de canal central qui va décoder un signal de canal central devant être envoyé au haut-parleur central. Le circuit de décodage de canal central comprend deux condensateurs de découplage qui vont découpler les signaux gauche et droit issus du signal stéréophonique amplifié en puissance, ceci avant de combiner ces signaux de manière à produire le signal du canal central. Cette action de découplage permet d'éviter tout 'épanchement' des signaux gauche et droit qui dégraderait le signal stéréophonique.
PCT/CA1997/000882 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround WO1999026455A1 (fr)

Priority Applications (9)

Application Number Priority Date Filing Date Title
CA002308576A CA2308576A1 (fr) 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround
ES97913055T ES2176716T3 (es) 1997-11-14 1997-11-14 Circuito descodificador de sonido estereofonico para obtener sonido envolvente, con post-amplificacion.
AT97913055T ATE218267T1 (de) 1997-11-14 1997-11-14 Stereo zu raumklang nachverstärkung- schalldekodierungsschaltung
EP97913055A EP1064824B1 (fr) 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround
PCT/CA1997/000882 WO1999026455A1 (fr) 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround
DE69712926T DE69712926T2 (de) 1997-11-14 1997-11-14 Stereo zu raumklang nachverstärkung- schalldekodierungsschaltung
DK97913055T DK1064824T3 (da) 1997-11-14 1997-11-14 Dekoderkredsløb for stereofonisk surround-sound
AU50453/98A AU748414B2 (en) 1997-11-14 1997-11-14 Post-amplification stereophonic to surround sound decoding circuit
JP2000521683A JP2001523937A (ja) 1997-11-14 1997-11-14 増幅後のステレオ音響サラウンドサウンドデコード回路

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CA1997/000882 WO1999026455A1 (fr) 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround

Publications (1)

Publication Number Publication Date
WO1999026455A1 true WO1999026455A1 (fr) 1999-05-27

Family

ID=4173249

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1997/000882 WO1999026455A1 (fr) 1997-11-14 1997-11-14 Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround

Country Status (9)

Country Link
EP (1) EP1064824B1 (fr)
JP (1) JP2001523937A (fr)
AT (1) ATE218267T1 (fr)
AU (1) AU748414B2 (fr)
CA (1) CA2308576A1 (fr)
DE (1) DE69712926T2 (fr)
DK (1) DK1064824T3 (fr)
ES (1) ES2176716T3 (fr)
WO (1) WO1999026455A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004098050A2 (fr) * 2003-04-24 2004-11-11 Dolby Laboratories Licensing Corporation Reglage du volume dans les cinemas
US7551745B2 (en) 2003-04-24 2009-06-23 Dolby Laboratories Licensing Corporation Volume and compression control in movie theaters
US8019350B2 (en) 2004-11-02 2011-09-13 Coding Technologies Ab Audio coding using de-correlated signals
US8731204B2 (en) 2004-09-08 2014-05-20 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Device and method for generating a multi-channel signal or a parameter data set

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104936090B (zh) * 2015-05-04 2018-12-14 联想(北京)有限公司 一种音频数据的处理方法和音频处理器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4132859A (en) * 1977-12-02 1979-01-02 Egils Ranga Sound reproducing apparatus
GB2014404A (en) * 1978-02-10 1979-08-22 Nissan Motor A stereophonic speaker system for use in an automotive vehicle
US4382157A (en) * 1978-07-17 1983-05-03 Kenneth P. Wert, Sr. Multiple speaker type sound producing system
US5265166A (en) * 1991-10-30 1993-11-23 Panor Corp. Multi-channel sound simulation system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4132859A (en) * 1977-12-02 1979-01-02 Egils Ranga Sound reproducing apparatus
GB2014404A (en) * 1978-02-10 1979-08-22 Nissan Motor A stereophonic speaker system for use in an automotive vehicle
US4382157A (en) * 1978-07-17 1983-05-03 Kenneth P. Wert, Sr. Multiple speaker type sound producing system
US5265166A (en) * 1991-10-30 1993-11-23 Panor Corp. Multi-channel sound simulation system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004098050A2 (fr) * 2003-04-24 2004-11-11 Dolby Laboratories Licensing Corporation Reglage du volume dans les cinemas
WO2004098050A3 (fr) * 2003-04-24 2005-01-27 Dolby Lab Licensing Corp Reglage du volume dans les cinemas
US7251337B2 (en) 2003-04-24 2007-07-31 Dolby Laboratories Licensing Corporation Volume control in movie theaters
US7551745B2 (en) 2003-04-24 2009-06-23 Dolby Laboratories Licensing Corporation Volume and compression control in movie theaters
USRE43132E1 (en) 2003-04-24 2012-01-24 Dolby Laboratories Licensing Corporation Volume control for audio signals
USRE44261E1 (en) 2003-04-24 2013-06-04 Dolby Laboratories Licensing Corporation Volume control for audio signals
USRE44929E1 (en) 2003-04-24 2014-06-03 Dolby Laboratories Licensing Corporation Volume control for audio signals
USRE45389E1 (en) 2003-04-24 2015-02-24 Dolby Laboratories Licensing Corporation Volume control for audio signals
USRE45569E1 (en) 2003-04-24 2015-06-16 Dolby Laboratories Licensing Corporation Volume control for audio signals
US8731204B2 (en) 2004-09-08 2014-05-20 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Device and method for generating a multi-channel signal or a parameter data set
US8019350B2 (en) 2004-11-02 2011-09-13 Coding Technologies Ab Audio coding using de-correlated signals

Also Published As

Publication number Publication date
EP1064824B1 (fr) 2002-05-29
CA2308576A1 (fr) 1999-05-27
DE69712926T2 (de) 2002-11-28
ES2176716T3 (es) 2002-12-01
AU748414B2 (en) 2002-06-06
DE69712926D1 (de) 2002-07-04
DK1064824T3 (da) 2002-09-16
AU5045398A (en) 1999-06-07
EP1064824A1 (fr) 2001-01-03
JP2001523937A (ja) 2001-11-27
ATE218267T1 (de) 2002-06-15

Similar Documents

Publication Publication Date Title
US6934394B1 (en) Universal four-channel surround sound speaker system for multimedia computer audio sub-systems
US5497425A (en) Multi channel surround sound simulation device
US7231053B2 (en) Enhanced multi-channel audio surround sound from front located loudspeakers
AU698935B2 (en) In-home theater surround sound speaker system
US5199075A (en) Surround sound loudspeakers and processor
US6118876A (en) Surround sound speaker system for improved spatial effects
US3757047A (en) Four channel sound reproduction system
US5386473A (en) Passive surround sound circuit
US5708719A (en) In-home theater surround sound speaker system
WO1997041711A1 (fr) Systeme ameliore d'ecoute utilisable dans un environnement sonore
WO1995030322A1 (fr) Appareil et procede de reglage des niveaux des canaux d'une chaine audio
US5265166A (en) Multi-channel sound simulation system
EP0687129B1 (fr) Dispositif générant un signal commun des graves
EP1064824B1 (fr) Circuit post-amplification de decodage du son depuis un mode stereophonique en un mode surround
KR19980024143A (ko) 실내극장 서라운드 사운드 스피커 시스템
US5175768A (en) Method and apparatus for enhancing the stereo effect in headsets having cross coupling voice coils
RU2193827C2 (ru) Постусилительная схема декодирования стереофонического звука в окружающий звук
JP2004511927A (ja) パラメトリックスピーカー用電力アンプ
MXPA00005869A (en) Post-amplification stereophonic to surround sound decoding circuit
US4843625A (en) Sound reproduction systems
US20040141619A1 (en) Method of generating a left modified and a right modified audio signal for a stereo system
GB2209110A (en) Sound reproduction system
JPH07111698A (ja) 音響再生装置

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 97182476.2

Country of ref document: CN

AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG US UZ VN

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH KE LS MW SD SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 09392918

Country of ref document: US

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

ENP Entry into the national phase

Ref document number: 2308576

Country of ref document: CA

Ref document number: 2308576

Country of ref document: CA

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: KR

WWE Wipo information: entry into national phase

Ref document number: 1997913055

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: PA/a/2000/005869

Country of ref document: MX

Ref document number: 50453/98

Country of ref document: AU

WWP Wipo information: published in national office

Ref document number: 1997913055

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 1997913055

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 50453/98

Country of ref document: AU