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US 5,319,713 AGranted

Multi dimensional sound circuit

AssigneeRocktron Corporation

InventorsJames K. Waller, Jr., Derek F. Bowers

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Abstract

An audio sound system decodes from non-encoded two-channel stereo into at least four channel sound. The rear channel information is derived by taking a difference of left minus right and dividing that difference into a plurality of bands. In a simplistic implementation, at least one band is dynamically steered while the other band is unaltered so as to avoid any perceived pumping effects while providing transient information to left/right, as well as directional enhancement. In a preferred embodiment, multiple bands are dynamically steered left or right, so as to enhance directional information to the rear of the listener. In both schemes, the low pass filtered output of the sum of the left and right inputs is also combined with the directionally enhanced information, so as to provide a composite left rear and right rear output. Furthermore, the center channel information does not necessarily require a discrete loudspeaker, and can be divided so that low frequency information can be applied to the rear channels while mid and high frequency information from the center channel can be applied to the front left and right channels to compensate for any perceived loss of center information.

Claims108

Dependent claims

Claim 1A circuit for decoding two channel stereo signals into multi-channel sound signals · 91 words2 dependent Claim 2A circuit for decoding two channel stereo signals into multi-channel sound signals · 132 words19 dependent Claim 24A circuit for decoding two channel stereo signals into multi-channel sound signals · 277 words12 dependent Claim 37A circuit for decoding two channel stereo signals into multi-channel sound signals · 262 words2 dependent Claim 40A circuit for decoding two channel stereo signals into multi-channel sound signals · 353 words1 dependent Claim 42A circuit for decoding two channel stereo signals into multi-channel sound signals · 129 words12 dependent Claim 55A method for decoding two channel stereo signals into multi-channel sound signals · 86 words2 dependent Claim 56A method for decoding two channel stereo signals into multi-channel sound signals · 117 words19 dependent Claim 78A method for decoding two channel stereo signals into multi-channel sound signals · 261 words12 dependent Claim 91A method for decoding two channel stereo signals into multi-channel sound signals · 247 words2 dependent Claim 94A method for decoding two channel stereo signals into multi-channel sound signals · 329 words1 dependent Claim 96A method for decoding two channel stereo signals into multi-channel sound signals · 120 words12 dependent

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing the two channel stereo signals to provide a primary signal;
means for dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
means for determining a dominant one of the two channel stereo signals;
and
means for dynamically varying the level of at least one of said split band signals in response to the dominant of the two channel stereo signals to produce an audio output signal.

2 more elements

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing the two channel stereo signals to provide a primary signal;
means for dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
means for dynamically varying the level of at least one of said split frequency band signals to produce a first dynamically varied signal;
and
means for controlling the gain of said varying means to increase the level of said first dynamically varied signal when the level of one of the two channel signals is high relative to the other and to decrease the level of said first dynamically varied-signal when the level of the other of the two channel signals is high relative to said one.

2 more elements

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing the two channel stereo signals to provide a primary signal;
means for dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
first means for dynamically varying the level of one of said split frequency band signals to provide a first dynamically varied signal;
second means for dynamically varying the level of another of said split frequency band signals to produce a second dynamically varied signal;
means for deriving a first dc signal proportional to one of the two channel stereo signals;
means for deriving a second dc signal proportional to the other of the two channel stereo signals;
means for differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
and
means for controlling the gain of said first varying means to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and for controlling the gain of said second varying means to increase the level of said second varied signal when the level of said other of the two channel signals is high and to decrease the level of said first varied signal when the level of said another of the two channel signals is high.

6 more elements

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing the two channel stereo signals to provide a primary signal;
means for shifting the phase of said primary signal to provide a phase-shifted signal;
first means for dynamically varying the level of said phase-shifted signal to provide a first dynamically varied signal;
second means for dynamically varying the level of said phase-shifted signal to produce a second dynamically varied signal;
means for deriving a first dc signal proportional to one of the two channel stereo signals;
means for deriving a second dc signal proportional to the other of the two channel stereo signals;
means for differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
and
means for controlling the gain of said first varying means to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and for controlling the gain of said second varying means to increase the level of said second varied signal when the level of the of the two channel signals is high and to decrease the level of said first varied signal when the level of the other of the two channel signals is high.

6 more elements

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing the two channel stereo signals to provide a primary signal;
means for shifting the phase of said primary signal to provide a phase-shifted signal;
first means for dynamically varying the level of said phase-shifted signal to provide a first dynamically varied signal;
second means for dynamically varying the level of said phase-shifted signal to produce a second dynamically varied signal;
means for deriving a first dc signal proportional to one of the two channel stereo signals;
means for deriving a second dc signal proportional to the other of the two channel stereo signals;
means for differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
means for controlling the gain of said first varying means to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and for controlling the gain of said second varying means to increase the level of said second varied signal when the level of the another of the two channel signals is high and to decrease the level cf said first varied signal when the level of the other of the two channel signals is high;
means for deriving low frequency response components of said one of said two channel stereo signals;
means for combining said low frequency response components of said one of said two channel stereo signals with said second dynamically varied signal to produce a first output signal;
means for deriving low frequency response components of said other of said two channel stereo signals;
and
means for combining said low frequency response components of said other of said two channel stereo signals with said first dynamically varied signal to produce a first output signal.

10 more elements

A circuit for decoding two channel stereo signals into multi-channel sound signals comprising:

means for differencing left and right channel stereo signals to provide a primary signal;
means for dividing said primary signal into high, mid and low frequency band signals;
means for determining a dominant one of the two channel stereo signals;
means for separately dynamically varying the level of each of said band signals in response to the dominant of said left and right channel stereo signals to provide right and left varied signals in each said band;
means for combining said right high, mid and low frequency varied band signals to produce a first output signal;
and
means for combining said left high, mid and low frequency varied band signals to produce a second output signal.

4 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising the steps of:

differencing the two channel stereo signals to provide a primary signal;
dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
and
determining a dominant one of the two channel stereo signals;
dynamically varying the level of at least one of said split band signals in response to the dominant of the two channel stereo signals to produce an audio output signal.

2 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising:

differencing the two channel stereo signals to provide a primary signal;
dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
dynamically varying the level of at least one of said split frequency band signals to produce a first dynamically varied signal;
and
controlling the gain of said varying means to increase the level of said first dynamically varied signal when the level of one of the two channel signals is high and to decrease the level of said first dynamically varied signal when the level of the other of the two channel signals is high.

2 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising the steps of:

differencing the two channel stereo signals to provide a primary signal;
dividing said primary signal into a plurality of bands to provide a plurality of split frequency band signals;
dynamically varying the level of one of said split frequency band signals to provide a first dynamically varied signal;
dynamically varying the level of another of said split frequency band signals to produce a second dynamically varied signal;
deriving a first dc signal proportional to one of the two channel stereo signals;
deriving a second dc signal proportional to the other of the two channel stereo signals;
differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
and
controlling the gain of said one varying step to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and controlling the gain of said another varying step to increase the level of said second varied signal when the level of said other of the two channel signals is high and to decrease the level of said first varied signal when the level of said other of the two channel signals is high.

6 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising the steps of:

differencing the two channel stereo signals to provide a primary signal;
shifting the phase of said primary signal to provide a phase-shifted signal;
dynamically varying the level of said phase-shifted signal to provide a first dynamically varied signal;
dynamically varying the level of said phase-shifted signal to produce a second dynamically varied signal;
deriving a first dc signal proportional to one of the two channel stereo signals;
deriving a second dc signal proportional to the other of the two channel stereo signals;
differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
and
controlling the gain of said first varying step to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and controlling the gain of said second varying step to increase the level of said second varied signal when the level of said other of the two channel signals is high and to decrease the level of said first varied signal when the level of said other of the two channel signals is high.

6 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising the steps of:

differencing the two channel stereo signals to provide a primary signal;
shifting the phase of said primary signal to provide a phase-shifted signal;
dynamically varying the level of said phase-shifted signal to provide a first dynamically varied signal;
dynamically varying the level of said phase-shifted signal to produce a second dynamically varied signal;
deriving a first dc signal proportional to one of the two channel stereo signals;
deriving a second dc signal proportional to the other of the two channel stereo signals;
differencing said first and second dc signals to provide a dc control signal which is positive when one of the two channel stereo signals is dominant and which is negative when the other of the two channel stereo signals is dominant;
controlling the gain of said first varying step to increase the level of said first varied signal when the level of said one of the two channel signals is high and to decrease the level of said second varied signal when the level of said one of the two channel signals is high and controlling the gain of said second varying step to increase the level of said second varied signal when the level of said other of the two channel signals is high and to decrease the level of said first varied signal when the level of said other of the two channel signals is high;
deriving low frequency response components of said one of said two channel stereo signals;
combining said low frequency response components of said one of said two channel stereo signals with said second dynamically varied signal to produce a first output signal;
deriving low frequency response components of said other of said two channel stereo signals;
and
combining said low frequency response components of said other of said two channel stereo signals with said first dynamically varied signal to produce a first output signal.

10 more elements

A method for decoding two channel stereo signals into multi-channel sound signals comprising the steps of:

differencing left and right channel stereo signals to provide a primary signal;
dividing said primary signal into high, mid and low frequency band signals;
determining a dominant one of the two channel stereo signals;
separately dynamically varying the level of each of said band signals in response to the dominant of said left and right channel stereo signals to provide right and left varied signals in each said band;
combining said right high, mid and low frequency varied band signals to produce a first output signal;
and
combining said left high, mid and low frequency varied band signals to produce a second output signal.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/975,612Filed 12 Nov 1992
Granted: 7 Jun 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification2 codes

H04S 3/02
Systems employing more than two channels, e.g. quadraphonic: of the matrix type, i.e. in which input signals are combined algebraically, e.g.…
H04S
Stereophonic systems

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