Abstract: A matrix system encodes five discrete audio signals down to a two-channel stereo recording and decodes the recorded stereo signal into at least five stand alone, independent channels to allow placement of specific sounds at any one of 5 or more predetermined locations as individual, independent sound sources, thus producing a 5-2-5 matrix system. One embodiment of the system provides signals to left front, right front, center, left rear, and right rear speaker locations. The matrix system is compatible with all existing stereo materials and material encoded for use with other existing surround systems. Material specifically encoded for this system can be played back through any other existing decoding systems without producing undesirable results.

Abstract: A matrix system encodes five discrete audio signals down to a two-channel stereo recording and decodes the recorded stereo signal into at least five stand alone, independent channels to allow placement of specific sounds at any one of 5 or more predetermined locations as individual, independent sound sources, thus producing a 5-2-5 matrix system. One embodiment of the system provides signals to left front, right front, center, left rear, and right rear speaker locations. The matrix system is compatible with all existing stereo materials and material encoded for use with other existing surround systems. Material specifically encoded for this system can be played back through any other existing decoding systems without producing undesirable results.

Abstract: An expandable multi-dimensional sound system has two modes of operation. Prior to the detection of a 20 kHz tone, the system is configured such that input audio panned hard to the left or right will result in the center and surround channels steering down so that the signal is only passed through the left front and right front channels, respectively. Mono information is fed only through the center channel, as the left and right front channels cancel any center channel or mono information. Material panned hard to the surround position steers down the front left and right channels and is only fed to the rear surround channels. No information is fed to the front center channel due to the fact that the signal contains only difference information. Directional steering to the rear channels is still provided in the absence of any hard broadband left or right panning. Upon the detection of a 20 kHz tone, the system is re-configured such that the left and right front channels and the center channel become disabled.

Abstract: An analog tape saturation simulator produces the same results as analog tape saturation in a controllable environment which can be user adjusted to the desirable level of saturation effect. A log-based audio detector receives the audio signal in front of a circuit limiting the maximum range over which a dynamic filter will operate to control the high frequency bandwidth via a voltage-controlled low pass filter which follows a soft-clipping distortion circuit also receiving the audio signal. The simulator provides dynamic changes to the signal based on the level of simulated saturation taking place. The simulator produces the nonlinear, soft clipping characteristics of overdriving analog tape and dynamically reduces the high frequency information in response to the input amplitude of the audio signal.

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.

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.