Multi-channel audio surround sound from front located loudspeakers
First Claim
1. An audio reproduction system comprising:
- a first audio input signal, a second audio input signal, a third audio input signal, and a fourth audio input signal;
a left main speaker and a right main speaker disposed respectively at left and right main speaker locations spaced along a speaker axis defined as a line passing through said left and right main speaker locations, with a listening area comprising the general area in front of the left and right main speaker locations such that the left main speaker location lies to the left and the right main speaker location lies to the right when viewed from the listening area, wherein said left and right main speakers reproduce sound associated with signals received by said left and right main speakers;
a left sub-speaker and a right sub-speaker disposed respectively at left and right sub-speaker locations, wherein the left and right sub-speaker locations lie approximately on the speaker axis such that the left and right sub-speaker locations as viewed from the listening area are located to the left and right respectively of the respective left and right main speaker locations and are spaced a distance d from the respective left and right main speaker locations such that the distance d is in the range from approximately 50% to 150% of the average spacing between a person'"'"'s ears as measured in a straight line through the head, wherein said left and right sub-speakers reproduce sound associate with signals received by them; and
signal modification and combination means, wherein said signal modification and combination means comprises, means for modifying and combining the first audio input signal with the second audio input signal and transmitting the combination of said modified first audio input signal and said second audio input signal to said left main speaker, means for modifying and combining the fourth audio input signal with the third audio input signal and transmitting the combination of said modified fourth audio input signal and said third audio input signal to said right main speaker, means for subtracting said modified fourth audio input signal from said modified first audio input signal and transmitting the resulting difference signal to said left sub-speaker, and means for subtracting said modified first audio input signal from said modified fourth audio input signal and transmitting the resulting difference signal to said right sub-speaker, wherein sound reproduced by the system that is associated with said second and third audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a range of sound locations approximately between said left and right main speakers, and wherein sound reproduced by the system that is associated with said first and fourth audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a broad range of sound locations extending beyond the locations of said left and right sub-speakers.
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Accused Products
Abstract
A surround sound reproduction system uses a series of filters and a system of main and sub-speakers to produce phantom rear surround sound channels or a phantom surround sound effect from a loudspeaker system or pair of loudspeaker systems located in front of the listener. The sound system includes left and right surround input signals, and left and right front input signals. Left and right sub-speakers, and left and right main speakers are located in front of a listening location. Spacing between respective main and sub-speakers is approximately equal to ear spacing for an average person. The input to the left sub-speaker comprises the right surround signal subtracted from the left surround signal each signal having previously passed through a front-to-back filter and a series of high and low pass filters. The input into the left main speaker comprises the left front signal added to the left surround signal after the left surround signal has passed through a front-to-back filter. The input into the right sub-speaker comprises the left surround signal subtracted from the right surround signal each signal having previously passed through a front-to-back filter and a series of high and low pass filters. The input into the right main speaker comprises the right front signal added to the right surround signal after the right surround signal has passed through a front-to-back filter.
89 Citations
59 Claims
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1. An audio reproduction system comprising:
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a first audio input signal, a second audio input signal, a third audio input signal, and a fourth audio input signal;
a left main speaker and a right main speaker disposed respectively at left and right main speaker locations spaced along a speaker axis defined as a line passing through said left and right main speaker locations, with a listening area comprising the general area in front of the left and right main speaker locations such that the left main speaker location lies to the left and the right main speaker location lies to the right when viewed from the listening area, wherein said left and right main speakers reproduce sound associated with signals received by said left and right main speakers;
a left sub-speaker and a right sub-speaker disposed respectively at left and right sub-speaker locations, wherein the left and right sub-speaker locations lie approximately on the speaker axis such that the left and right sub-speaker locations as viewed from the listening area are located to the left and right respectively of the respective left and right main speaker locations and are spaced a distance d from the respective left and right main speaker locations such that the distance d is in the range from approximately 50% to 150% of the average spacing between a person'"'"'s ears as measured in a straight line through the head, wherein said left and right sub-speakers reproduce sound associate with signals received by them; and
signal modification and combination means, wherein said signal modification and combination means comprises, means for modifying and combining the first audio input signal with the second audio input signal and transmitting the combination of said modified first audio input signal and said second audio input signal to said left main speaker, means for modifying and combining the fourth audio input signal with the third audio input signal and transmitting the combination of said modified fourth audio input signal and said third audio input signal to said right main speaker, means for subtracting said modified fourth audio input signal from said modified first audio input signal and transmitting the resulting difference signal to said left sub-speaker, and means for subtracting said modified first audio input signal from said modified fourth audio input signal and transmitting the resulting difference signal to said right sub-speaker, wherein sound reproduced by the system that is associated with said second and third audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a range of sound locations approximately between said left and right main speakers, and wherein sound reproduced by the system that is associated with said first and fourth audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a broad range of sound locations extending beyond the locations of said left and right sub-speakers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 28, 29, 30)
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25. An audio reproduction system comprising:
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a first audio input signal, a second audio input signal, a third audio input signal, and a fourth audio input signal;
a left main speaker and a right main speaker disposed respectively at left and right main speaker locations spaced along a speaker axis defined as a line passing through said left and right main speaker locations, with a listening area comprising the general area in front of the left and right main speaker locations such that the left main speaker location lies to the left and the right main speaker location lies to the right when viewed from the listening area, wherein said left and right main speakers reproduce sound associated with signals received by them;
a left front speaker and a right front speaker located respectively at left and right front speaker locations generally in front of a listener in the listening area, wherein said left and right front speakers reproduce sound associated with signals received by them;
a left sub-speaker and a right sub-speaker disposed respectively at left and right sub-speaker locations, wherein the left and right sub-speaker locations lie approximately on the speaker axis such that the left and right sub-speaker locations as viewed from the listening area are located to the left and right respectively of the respective left and right main speaker locations and are spaced a distance d from the respective left and right main speaker locations such that the distance d is in the range from approximately 50% to 150% of the average spacing between a person'"'"'s ears as measured in a straight line through the head, wherein said left and right sub-speakers reproduce sound associated with signals received by them; and
signal modification and combination means, wherein said signal modification and combination means comprises, means for transmitting the second audio input signal to the left front speaker and the third audio input signal to the right front speaker;
means for modifying the first audio input signal and transmitting the modified first audio input signal to said left main speaker, means for modifying fourth audio input signal and transmitting the modified fourth audio input signal to said right main speaker, means for subtracting the modified fourth audio input signal from the modified first audio input signal and transmitting the resulting difference signal to said left sub-speaker, and means for subtracting the modified first audio input signal from the modified fourth audio input signal and transmitting the resulting difference signal to said right sub-speaker, wherein sound reproduced by the system associated with said second and third audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a range of sound locations approximately between said left front speaker and said right front speaker, and wherein sound reproduced by the system that is associated with said first and fourth audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a broad range of sound locations extending beyond the locations of said left and right sub-speakers. - View Dependent Claims (26, 27)
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31. A method for producing phantom surround sound effect from a loudspeaker system located in front of a listener, comprising the steps of:
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providing a left main speaker and a right main speaker disposed respectively at left and right main speaker locations spaced along a speaker axis defined as a line passing through said left and right main speaker locations, with a listening area comprising the general area in front of the left and right main speaker locations such that the left main speaker location lies to the left and the right main speaker location lies to the right when viewed from the listening area;
providing a left sub-speaker and a right sub-speaker disposes respectively at left and right sub-speaker locations, wherein the left and right sub-speaker locations lie approximately on the speaker axis such that the left and right sub-speaker locations as viewed from the listening area are located to the left and right respectively of the respective left and right main speaker locations and are spaced a distance d from the respective left and right main speaker locations such that the distance d is in the range from approximately 50% to 150% of the average spacing between a person'"'"'s ears as measured in a straight line through the head;
modifying a first audio input signal and combining the modified first audio input signal with a second audio input signal, transmitting the combination of the modified first audio input signal and the second audio input signal to the left main speaker, and reproducing sound associated with the combination of the modified first audio input signal and the second audio input signal in the left main speaker;
modifying a fourth audio input signal and combining the modified fourth audio input signal with a third audio input signal, transmitting the combination of the modified fourth audio input signal and the third audio input signal to the right main speaker, and reproducing the sound associated with the combination of the modified fourth audio input signal and the third audio input signal in the right main speaker;
subtracting the modified fourth audio input signal from the modified first audio input signal, transmitting the resulting difference signal to the left sub-speaker, and reproducing sound associated with the difference signal in the left sub-speaker; and
subtracting the modified first audio input signal from the modified fourth audio input signal, transmitting the resulting difference signal to the right sub-speaker, and reproducing sound associated with the difference signal in the right sub-speaker, wherein the reproduced sound associated with the second and third audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a range of sound locations approximately between said left and right main speakers, and wherein the reproduced sound associated with the first and fourth audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a broad range of sound locations extending beyond the locations of said left and right sub-speakers. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 58, 59)
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55. A method for producing phantom surround sound effect from a loudspeaker system located in front of a listener, comprising the steps of:
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providing a left main speaker and a right main speaker disposed respectively at left and right main speaker locations spaced along a speaker axis defined as a line passing through said left and right main speaker locations, with a listening area comprising the general area in front of the left and right main speaker locations such that the left main speaker location lies to the left and the right main speaker location lies to the right when viewed from the listening area;
providing a left front speaker and a right front speaker disposed generally in front of a listener in the listening area;
providing a left sub-speaker and a right sub-speaker disposed respectively at left and right sub-speaker locations, wherein the left and right sub-speaker locations lie approximately on the speaker axis such that the left and right sub-speaker locations as viewed from the listening area are located to the left and right respectively of the respective left and right main speaker locations and are spaced a distance d from the respective left and right main speaker locations such that the distance d is in the range from approximately 50% to 150% of the average spacing between a person'"'"'s ears as measured in a straight line through the head;
modifying a first audio input signal, transmitting the modified first audio input signal to the left main speaker, and reproducing sound associated with the modified first audio input signal in the left main speaker;
modifying a fourth audio input signal, transmitting the modified fourth audio input signal to the right main speaker, and reproducing the sound associated with the modified fourth audio input signal in the right main speaker;
transmitting a second audio input signal to the left front speaker and reproducing sound associated with the second audio input signal in the left front speaker;
transmitting a third audio input signal to the right front speaker and reproducing sound associated with the third audio input signal in the right front speaker;
subtracting the modified fourth audio input signal from the modified first audio input signal, transmitting the resulting difference signal to the left sub-speaker, and reproducing sound associated with the difference signal in the left sub-speaker; and
subtracting the modified first audio input signal from the modified fourth audio input signal, transmitting the resulting difference signal to the right sub-speaker, and reproducing sound associated with the difference signal in the right sub-speaker;
wherein the reproduced sound associated with the second and third audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a range of sound locations approximately between the left front speaker and the right front speaker;
wherein the reproduced sound associated with the first and fourth audio input signals is perceived by a listener located in the listening area whose head is oriented generally toward the speaker locations to originate from a broad range of sound locations extending beyond the locations of said left and right sub-speakers. - View Dependent Claims (56, 57)
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Specification