Method and apparatus for reproducing sound having a realistic ambient field and acoustic image
First Claim
1. In a stereophonic sound reproduction system having a left channel output and a right channel output, apparatus for reproducing sound having a realistic ambient field and acoustic image comprising:
- a right main speaker and a left main speaker disposed respectively at right and left main speaker locations equidistantly spaced from a listening location, the listening location being a place in space for accommodating a listener'"'"'s head facing the main speakers and having a right ear location and a left ear location along an ear axis, with the right and left ear locations separated along the ear axis by a maximum interaural sound distance of Δ
tmax'"'"' and the listening location being defined as the point on the ear axis equidistant to the right and left ears;
a right sub-speaker and a left sub-speaker disposed respectively at right and left sub-speaker locations equidistantly spaced from the listening location;
the right main speaker being separated from the right ear location by a sound distance t and being separated from the left ear by a sound distance t+Δ
t where Δ
t is the interaural sound distance of the right and left ear locations with respect to the right main speaker;
the right sub-speaker being separated from the right ear location by a sound distance t+Δ
t'"'"' where Δ
t'"'"' is the sound distance spacing with respect to the right ear location between the right main speaker location and right sub-speaker location;
the left main speaker being separated from the left ear location by a sound distance t and being separated from the right ear location by a sound distance t+Δ
t where Δ
t is the interaural sound distance between the left and right ear locations with respect to the left main speaker;
the left sub-speaker being separated from the left ear location by a sound distance t+Δ
t'"'"' where Δ
t, is the sound distance spacing with respect to the left ear location between the left main speaker location and left sub-speaker location;
the main speaker locations and sub-speaker locations being spaced from the listening location in a manner such that Δ
t+Δ
t'"'"' is <
Δ
tmax ;
each of said left and right main speakers and left and right sub-speakers comprising a driver and a tweeter, and wherein each of said sub-speaker drivers are positioned physically further from the listening location than the sub-speaker tweeters, cross-over networks for providing transition between corresponding drivers and tweeters at approximately 1 KHz so that the inter-speaker delay between a main speaker and its sub-speaker with respect to the listening location is greater for frequencies below approximately 1 KHz than for higher frequencies;
means coupling the right and left channel outputs, respectively, to said right and left main speakers;
means connected to the right and left channel outputs for developing a left channel minus right channel signal and a right channel minus left channel signal;
means coupling said left channel minus right channel signal to said left sub-speaker and said right channel minus left channel signal to said right sub-speaker;
whereby sound reproduced by said apparatus as perceived by a listener whose head is located generally at the listening location has a realistic acoustic field and enhanced acoustic image.
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Abstract
Apparatus for reproducing sound having a realistic ambient field and acoustic image is used in a stereophonic sound reproduction system having a left channel output and a right channel output. A right main speaker and a left main speaker are disposed at right and left main speaker locations, respectively, which are equidistantly spaced from a listening location along a listening axis perpendicular to a line joining the left and right main speakers. A right sub-speaker and a left sub-speaker are respectively disposed at right and left sub-speaker locations equidistantly spaced from the listening location, and further from the listening location than the main speaker. In one particular arrangement each sub-speaker includes a driver and a tweeter, with the driver spaced a distance approximately 50% further from the main speaker location than the tweeter. The left and right channel outputs are respectively coupled to the left and right main speakers. A left channel minus right channel difference signal is coupled to the left sub-speaker and a right channel minus left channel difference signal is coupled to the right sub-speaker. In one embodiment, the main and sub-speakers for each channel are respectively incorporated in a common enclosure to fix the spacing therebetween. A technique for determining optimal spacing between the main and sub-speakers and between the various speakers and the listening location is set forth.
88 Citations
8 Claims
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1. In a stereophonic sound reproduction system having a left channel output and a right channel output, apparatus for reproducing sound having a realistic ambient field and acoustic image comprising:
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a right main speaker and a left main speaker disposed respectively at right and left main speaker locations equidistantly spaced from a listening location, the listening location being a place in space for accommodating a listener'"'"'s head facing the main speakers and having a right ear location and a left ear location along an ear axis, with the right and left ear locations separated along the ear axis by a maximum interaural sound distance of Δ
tmax'"'"' and the listening location being defined as the point on the ear axis equidistant to the right and left ears;a right sub-speaker and a left sub-speaker disposed respectively at right and left sub-speaker locations equidistantly spaced from the listening location; the right main speaker being separated from the right ear location by a sound distance t and being separated from the left ear by a sound distance t+Δ
t where Δ
t is the interaural sound distance of the right and left ear locations with respect to the right main speaker;the right sub-speaker being separated from the right ear location by a sound distance t+Δ
t'"'"' where Δ
t'"'"' is the sound distance spacing with respect to the right ear location between the right main speaker location and right sub-speaker location;the left main speaker being separated from the left ear location by a sound distance t and being separated from the right ear location by a sound distance t+Δ
t where Δ
t is the interaural sound distance between the left and right ear locations with respect to the left main speaker;the left sub-speaker being separated from the left ear location by a sound distance t+Δ
t'"'"' where Δ
t, is the sound distance spacing with respect to the left ear location between the left main speaker location and left sub-speaker location;the main speaker locations and sub-speaker locations being spaced from the listening location in a manner such that Δ
t+Δ
t'"'"' is <
Δ
tmax ;each of said left and right main speakers and left and right sub-speakers comprising a driver and a tweeter, and wherein each of said sub-speaker drivers are positioned physically further from the listening location than the sub-speaker tweeters, cross-over networks for providing transition between corresponding drivers and tweeters at approximately 1 KHz so that the inter-speaker delay between a main speaker and its sub-speaker with respect to the listening location is greater for frequencies below approximately 1 KHz than for higher frequencies; means coupling the right and left channel outputs, respectively, to said right and left main speakers; means connected to the right and left channel outputs for developing a left channel minus right channel signal and a right channel minus left channel signal; means coupling said left channel minus right channel signal to said left sub-speaker and said right channel minus left channel signal to said right sub-speaker; whereby sound reproduced by said apparatus as perceived by a listener whose head is located generally at the listening location has a realistic acoustic field and enhanced acoustic image.
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2. In a stereophonic sound reproduction system having a left channel output and a right channel output, apparatus for reproducing sound having a realistic ambient field and acoustic image comprising:
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right and left main speakers each comprising a driver and tweeter, said right and left main speakers disposed respectively at right and left main speaker locations equidistantly spaced from a listening location; right and left sub-speakers spaced respectively from said right and left main speakers so as to be further from the listening location than the main speakers and each comprising a driver and a tweeter, said sub-speaker tweeters being respectively spaced a first predetermined distance from the right and left main speaker locations, said sub-speaker drivers being spaced a second predetermined distance respectively from the right and left main speaker locations, said second predetermined distance being greater than said first predetermined distance; coupling means for respectively coupling the right and left channel outputs to said right and left main speakers and for coupling the left channel output minus the right channel output to said left sub-speaker and the right channel output minus the left channel output to said right sub-speaker, said coupling means including crossover networks for effecting a transition between drivers and tweeters at a sound frequency of approximately 1 KHz. - View Dependent Claims (3, 4, 5)
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6. A method for reproducing sound from a stereophonic source having a left channel output and a right channel output in which the reproduced sound has a realistic ambient field and acoustic image comprising the steps of:
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disposing a right main speaker and left main speaker at right and left main speaker locations equidistantly spaced from a listening location, each of said main speakers comprising a driver and a tweeter; disposing right and left sub-speakers each comprising a driver and tweeter at locations spaced respectively from the right and left main speaker locations so as to be further from the listening location than the main speaker locations, the sub-speaker tweeters being disposed a first predetermined distance from respective main speaker locations and the sub-speaker drivers being disposed a second predetermined distance from respective main speaker locations, the second predetermined distance being greater than the first predetermined distance; coupling the right and left channel outputs to the respective right and left main speakers and the left channel output minus the right channel output to the left sub-speaker and the right channel output minus the left channel output to the right sub-speaker; and providing cross-over networks for effecting transition between drivers and tweeter at a sound frequency of approximately 1 KHz. - View Dependent Claims (7, 8)
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Specification