US 4,118,599 A · Stereophonic sound reproduction system

Abstract

A stereophonic sound reproduction system comprises a first signal converter receptive of an audio signal for converting it into a binaural signal containing information as to the localization of the original sound source at a desired location in a listening area, and a second signal converter for converting the binaural signal into a signal containing no acoustic components which would produce the effect of crosstalk between listener's ears when the signal is reproduced in the listening area. A sound field expansion system is also disclosed which includes a converter which processes an input signal for generating an acoustic signal which localizes virtual sound sources so that the listener is given the impression of an expanded listening area.

Claims13

Dependent claims

Apparatus for deriving signals to be applied to a multi-channel sterophony using loudspeakers in spaced relation with respect to a listener, comprising;

binaural localization circuit means receptive of signals from a first signal source for developing a binaural representation of said first signal, said binaural representation consisting of first and second binaurally correlated signals which localize a binaural sonic image at a desired location;
and
crosstalk cancellation circuit means receptive of said first and second binaurally correlated signals for developing third and fourth binaurally correlated signals for application to said loudspeakers without producing the effect of acoustic crosstalk which might be preceptible by said listener if said first and second binaurally correlated signals were supplied directly to said loudspeakers.

Apparatus adapted to receive stereophonic signals for deriving signals to be applied to a multi-channel sterophony using loudspeakers in spaced relation with respect to a listener to give him a sense of an expanded stage width, comprising:

first and second filter-and-delay networks receptive of said stereophonic signals over separate channels and each having a transfer characteristic A.sub.i /A wherein A represents a transmission characteristic over an acoustic path between a said loudspeaker and a said listener'r ear nearer to said loudspeaker, and A.sub.i represents a transmission characteristic over an acoustic path between said listener's ear and a hypothetical sound reproduction source located at one end of said stage width nearer to said listener's ear;
third and fourth filter-and-delay networks connected respectively to the outputs of said first and second filter-and-delay networks, each having a transfer characteristic (B.sub.i /A.sub.i) (A/B), wherein B represents a transmission characteristic over an acoustic path between a said loudspeaker and the listener's other ear, and B.sub.i represents a transmission characteristic over an acoustic path between said hypothetical sound reproduction source and said listener's the other ear;
first and second adders each having first and second input terminals and an output terminal, the first input terminal of the first adder being receptive of the output from said first filter-and-delay network and the first input terminal of the second adder being receptive of the output from said second filter-and-delay network;
first and second subtractors each having positive and negative input terminals and an output terminal, the positive input terminal of the first subtractor being connected to receive the output from said third filter-and-delay network and the positive input terminal of the second subtractor being connected to receive the output from said fourth filter-and-delay network;
and
fifth and sixth filter-and-delay networks each having a transfer chacteristic B/A, the fifth filter-and-delay network being connected between the output of said first subtractor and the second input terminal of the second adder, and the sixth filter-and-delay network being connected between the output of said second subtractor and the second input terminal of said first adder, the output of said first adder being connected to the negative input terminal of said first subtractor and the output of said second adder being connected to the negative input terminal of said second subtractor, the outputs of said first and second adders being the signals for said multichannel sterephony.

3 more elements

Apparatus adapted to receive first and second stereophonic signals for deriving signals to be applied to a multi-channel sterophony using loudspeakers in spaced relation with respect to a listener to give him a sense of an expanded stage width, comprising:

first and second adders each having first and second input terminals and an output terminal, the first input terminals of the first and second adders being separately receptive of said first and second sterophonic signals;
first and second subtractors each having positive and negative input terminals and an output terminal:
a pair of ganged first and second variable attenuators, the first attenuator being connected between said first input terminal of said first adder and the positive input terminal of the first subtractor, the second attenuator being connected between said second input terminal of said second adder and the positive input terminal of said second subtractor;
first and second filter-and-delay networks each having a transfer characteristic B/A wherein A represents a transmission characteristic over an acoustic path between a said loudspeaker and a said listener's ear nearer to said loudspeaker, and B represents a transmission characteristic over an acoustic path between said loudspeaker and the listener's other ear, the first filter-and-delay network being connected between the output of said first subtractor and the second input of said second adder, and the second filter-and-delay network being connected between the output of said second subtractor and the second input of said first adder;
and
a pair of ganged third and fourth variable attenuators, the third attenuator being connected between the output of said first adder and the negative input terminal of said first subtractor, and the fourth attenuator being connected between the output of said second adder and the negative input terminal of said second subtractor, the outputs of said first and second adders being the signals for said multi-channel sterophony.

3 more elements

Apparatus adapted to receive sterophonic signals for deriving signals to be applied to a multi-channel stereophony using loudspeakers in spaced relation with respect to a listener to give him a sense of an expanded stage with, comprising:

localization circuit means receptive of said stereophonic signals for developing a binaural representation of said stereophonic signals, said binaural representation consisting of first and second binaurally correlated signals which localize a binaural sonic image at a desired location in said stage width;
and
crosstalk cancellation circuit means receptive of said first and second binaurally correlated signals for developing third and fourth binaurally correlated signals for application to said loudspeakers without producing the effect of acoustic crosstalks which might be perceptible by said listener if said first and second binaurally correlated signals were separately supplied directly to said loudspeakers.

A quadraphonic signal processing system comprising:

a pair of front-right and front-left output terminals for connection to a pair of front-right and front-left loudspeakers respectively which are disposed a predetermined equal distance from each other in front of a listener;
a pair of rear-right and rear-left output terminals for connection to a pair of rear-right and rear-left loudspeakers respectively which are disposed a predetermined equal distance from each other at the rear end of the listener;
first signal converter means receptive of an audio input signal for converting the same into a pair of binaural signals which carry information as to the localization of a binaural sonic image at a desired location, said converter means including first filter means receptive of said audio input signal for converting the same into a first signal and having a frequency response characteristic determined by the location of said sonic image, and second filter means receptive of said first signal for converting the same into a second signal and having a frequency response characteristic which represents the difference in intensity and propagation time over the frequency range of said first signal between a first and a second acoustic signal which would be received at respective ears of the listener seated with respect to said sonic image;
second signal converter means having right- and left- channel input terminals receptive of said first and second signals from the first signal converter means respectively for converting said first and second signals into front-right and front-left signals which, when reproduced by said front-right and front-left loudspeakers, will produce no acoustic crosstalks at the listener's ears;
third signal converter means having right- and left- channel input terminals receptive of said first and second signals from said first signal converter means respectively for converting said first and second signals into rear-right and rear-left signals which, when reproduced by said rear-right and rear-left loudspeakers, will produce no acoustic crosstalks at the listener's ears;
and
means for delivering said front-right and front-left signals from the second signals converter means and said rear-right and rear-left signals from the third signal converter means to said front-right and front-left output terminals and said rear-right and rear-left output terminals, respectively.

4 more elements

Dependencies are inferred from the claim text.

Abstract

Claims13

Dependent claims

Apparatus for deriving signals to be applied to a multi-channel sterophony using loudspeakers in spaced relation with respect to a listener, comprising;

binaural localization circuit means receptive of signals from a first signal source for developing a binaural representation of said first signal, said binaural representation consisting of first and second binaurally correlated signals which localize a binaural sonic image at a desired location;
and
crosstalk cancellation circuit means receptive of said first and second binaurally correlated signals for developing third and fourth binaurally correlated signals for application to said loudspeakers without producing the effect of acoustic crosstalk which might be preceptible by said listener if said first and second binaurally correlated signals were supplied directly to said loudspeakers.

first and second filter-and-delay networks receptive of said stereophonic signals over separate channels and each having a transfer characteristic A.sub.i /A wherein A represents a transmission characteristic over an acoustic path between a said loudspeaker and a said listener'r ear nearer to said loudspeaker, and A.sub.i represents a transmission characteristic over an acoustic path between said listener's ear and a hypothetical sound reproduction source located at one end of said stage width nearer to said listener's ear;
third and fourth filter-and-delay networks connected respectively to the outputs of said first and second filter-and-delay networks, each having a transfer characteristic (B.sub.i /A.sub.i) (A/B), wherein B represents a transmission characteristic over an acoustic path between a said loudspeaker and the listener's other ear, and B.sub.i represents a transmission characteristic over an acoustic path between said hypothetical sound reproduction source and said listener's the other ear;
first and second adders each having first and second input terminals and an output terminal, the first input terminal of the first adder being receptive of the output from said first filter-and-delay network and the first input terminal of the second adder being receptive of the output from said second filter-and-delay network;
first and second subtractors each having positive and negative input terminals and an output terminal, the positive input terminal of the first subtractor being connected to receive the output from said third filter-and-delay network and the positive input terminal of the second subtractor being connected to receive the output from said fourth filter-and-delay network;
and
fifth and sixth filter-and-delay networks each having a transfer chacteristic B/A, the fifth filter-and-delay network being connected between the output of said first subtractor and the second input terminal of the second adder, and the sixth filter-and-delay network being connected between the output of said second subtractor and the second input terminal of said first adder, the output of said first adder being connected to the negative input terminal of said first subtractor and the output of said second adder being connected to the negative input terminal of said second subtractor, the outputs of said first and second adders being the signals for said multichannel sterephony.

3 more elements

first and second adders each having first and second input terminals and an output terminal, the first input terminals of the first and second adders being separately receptive of said first and second sterophonic signals;
first and second subtractors each having positive and negative input terminals and an output terminal:
a pair of ganged first and second variable attenuators, the first attenuator being connected between said first input terminal of said first adder and the positive input terminal of the first subtractor, the second attenuator being connected between said second input terminal of said second adder and the positive input terminal of said second subtractor;
first and second filter-and-delay networks each having a transfer characteristic B/A wherein A represents a transmission characteristic over an acoustic path between a said loudspeaker and a said listener's ear nearer to said loudspeaker, and B represents a transmission characteristic over an acoustic path between said loudspeaker and the listener's other ear, the first filter-and-delay network being connected between the output of said first subtractor and the second input of said second adder, and the second filter-and-delay network being connected between the output of said second subtractor and the second input of said first adder;
and
a pair of ganged third and fourth variable attenuators, the third attenuator being connected between the output of said first adder and the negative input terminal of said first subtractor, and the fourth attenuator being connected between the output of said second adder and the negative input terminal of said second subtractor, the outputs of said first and second adders being the signals for said multi-channel sterophony.

3 more elements

localization circuit means receptive of said stereophonic signals for developing a binaural representation of said stereophonic signals, said binaural representation consisting of first and second binaurally correlated signals which localize a binaural sonic image at a desired location in said stage width;
and
crosstalk cancellation circuit means receptive of said first and second binaurally correlated signals for developing third and fourth binaurally correlated signals for application to said loudspeakers without producing the effect of acoustic crosstalks which might be perceptible by said listener if said first and second binaurally correlated signals were separately supplied directly to said loudspeakers.

A quadraphonic signal processing system comprising:

a pair of front-right and front-left output terminals for connection to a pair of front-right and front-left loudspeakers respectively which are disposed a predetermined equal distance from each other in front of a listener;
a pair of rear-right and rear-left output terminals for connection to a pair of rear-right and rear-left loudspeakers respectively which are disposed a predetermined equal distance from each other at the rear end of the listener;
first signal converter means receptive of an audio input signal for converting the same into a pair of binaural signals which carry information as to the localization of a binaural sonic image at a desired location, said converter means including first filter means receptive of said audio input signal for converting the same into a first signal and having a frequency response characteristic determined by the location of said sonic image, and second filter means receptive of said first signal for converting the same into a second signal and having a frequency response characteristic which represents the difference in intensity and propagation time over the frequency range of said first signal between a first and a second acoustic signal which would be received at respective ears of the listener seated with respect to said sonic image;
second signal converter means having right- and left- channel input terminals receptive of said first and second signals from the first signal converter means respectively for converting said first and second signals into front-right and front-left signals which, when reproduced by said front-right and front-left loudspeakers, will produce no acoustic crosstalks at the listener's ears;
third signal converter means having right- and left- channel input terminals receptive of said first and second signals from said first signal converter means respectively for converting said first and second signals into rear-right and rear-left signals which, when reproduced by said rear-right and rear-left loudspeakers, will produce no acoustic crosstalks at the listener's ears;
and
means for delivering said front-right and front-left signals from the second signals converter means and said rear-right and rear-left signals from the third signal converter means to said front-right and front-left output terminals and said rear-right and rear-left output terminals, respectively.

4 more elements

Dependencies are inferred from the claim text.

Stereophonic sound reproduction system

Life of this patent

Abstract

Claims13

Stereophonic sound reproduction system

Life of this patent

Abstract

Claims13