Stereo image separation and perimeter enhancement

A method for enhancing perimeter sounds in a stereo system having two loud speakers, one each associated with left and right stereo channels comprising the steps of:

• deriving a difference signal from the signals in the left and right stereo channels;
• delaying the difference signal;
• amplifying the delayed signal;
• phase splitting the amplified signal;
• and,
• coupling the phase split signal into the left and right channels so as to subtract delayed left minus right and right minus left components from correspondingly opposite channels.

A method for enhancing stereo separation in a stereo system having two loud speakers, one each associated with left and right stereo channels comprising the steps of:

• deriving a difference signal from the signals in the left and right stereo channels;
• delaying the difference signal;
• phase splitting the delayed signal;
• and,
• coupling the phase split signal into the left and right channels so as to subtract pure left minus right and right minus left signals from correspondingly opposite channels.

Apparatus for stereo image separation and perimeter enhancement for use with stereophonic audio reproduction means having left and right channel outputs and corresponding loud speakers comprising:

• means for deriving a difference signal from the signals in said left and right channels;
• means for delaying said difference signal;
• means coupled to said delay means for phase splitting said delayed signal and coupling the phase split delayed signal into said left and right channels so as to subtract delayed left minus right and right minus left components from the correspondingly opposite channels;
• and,
• means for delaying the signals in a channel after said subtraction to compensate for off-center listening for the channel the speaker of which is closer to the listener.

A method of obtaining short delays with clocked bucket brigade devices, comprising the steps of:

• delaying one signal with a bucket brigade analog delay line clocked at one clocking rate;
• delaying another signal with a second bucket brigade analog delay line clocked at a different rate;
• and,
• combining the delayed signals so as to obtain a delay which is the difference in delays engendered by the different clocking rates.

A method of obtaining short delays for acoustic signals in left and right stereo channels comprising the steps of:

• delaying the signals in both the left and right channels by a predetermined amount;
• deriving a difference signal from the signals in the left and right channels;
• delaying the difference signal by an amount different from the first delaying step;
• and,
• subtracting the delayed difference signal from a delayed channel signal.

Apparatus for obtaining short delays of a signal with clocked bucket brigade devices, comprising:

• means for delaying said signal with a bucket brigade analog delay line clocked at one clocking rate;
• means for delaying a reference signal with a second bucket brigade analog delay line clocked at a different rate;
• and,
• means for combining the delayed signals so as to obtain a signal delayed by the difference in delays engendered by the different clocking rates.

Apparatus for obtaining short delays for acoustic signals in left and right stereo channels comprising:

• means for delaying the signals in both the left and right channels by a predetermined amount;
• means for deriving a difference signal from the signals in the left and right channels;
• means for delaying the difference signal by an amount different from the first mentioned delaying means;
• and,
• means for subtracting the delayed difference signal from a delayed channel signal.