Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment acoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to a cross-talk cancellation and naturalization compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including cross-coupling while permitting listener movement by limiting the cross-talk cancellation and diffraction compensation to frequencies substantially below approximately ten kilohertz.

Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment acoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to a cross-talk cancellation and naturalization compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including cross-coupling while permitting listener movement by limiting the cross-talk cancellation and diffraction compensation to frequencies substantially below approximately ten kilohertz.

Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment acoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to a cross-talk cancellation and naturalization compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including cross-coupling while permitting listener movement by limiting the cross-talk cancellation and diffraction compensation to frequencies substantially below approximately ten kilohertz.

Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment acoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to an equalization circuit with the outputs coupled to a cross-talk cancellation compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including equalization and cross-coupling while permitting listener movement by modifying the cross-talk cancellation and diffraction compensation at frequencies substantially above approximately ten kilohertz while maintaining substantially accurate equalization for the desired incidence angle.

Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment accoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to an equalization circuit with the outputs coupled to a cross-talk cancellation compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including equalization and cross-coupling while permitting listener movement by modifying the cross-talk cancellation and diffraction compensation at frequencies substantially above approximately ten kilohertz while maintaining substantially accurate equalization for the desired incidence angle.

Abstract: A stereo audio processing system for a stereo audio signal processing reproduction that provides improved source imaging and simulation of desired listening environment acoustics while retaining relative independence of listener movement. The system first utilizes a synthetic or artificial head microphone pickup and utilizes the results as inputs to a cross-talk cancellation and naturalization compensation circuit utilizing minimum phase filter circuits to adapt the head diffraction compensated signals for use as loudspeaker signals. The system provides for head diffraction compensation including cross-coupling while permitting listener movement by limiting the cross-talk cancellation and diffraction compensation to frequencies substantially below approximately ten kilohertz.

Abstract: Multidirectional sound signals are optimally matrixed to increase the psychoacoustic directional fidelity as compared with prior systems. Four (or more) azimuthally spaced loudspeakers are fed from two transmission channels with very satisfactory directional sensing accuracy and full compatibility with conventional single-channel and two-channel reproduction equipment. Further auxiliary transmission channels may be added to produce a form of discrete-channel capability having even greater azimuthai fidelity than obtained in speaker-identifed channels, while at the same time maintaining compatibility both with conventional reproducing equipment and with equipment for the basic two-channel transmission of the invention. The auxiliary channels may be transmitted in a relatively narrow frequency range, thus reducing the total bandwidth requirement for recording or broadcasting as compared with full conventional discrete channels.

Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.

Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.

Abstract: A device which reduces beat distortion caused by crosstalk between subchannel signals in a multichannel sound system. To effect reduced beat distortion, one component present in both the sum and difference subchannel is attenuated before the subchannels are modulated.

Abstract: A method and apparatus is disclosed for reducing crossover modulation distortion generated at a sub-channel and for minimizing phase differences between 4-channel signals that are recorded on a recording medium in a multiple-frequency manner. More specifically, the present invention is directed to reducing or eliminating the beat distortion that is caused by crosstalk between a sub-channel signal and a main channel signal when the main channel signal is recorded according to RIAA-TYPE recording characteristics.

Abstract: Multidirectional source signals which are encoded in two monaural and stereo-compatible transmission channels with predetermined amplitude and phase relations indicative of source directions and adapted to be decoded for formation of more than two loudspeaker presentation signals having source signals corresponding to every source direction appearing in a plurality of such presentation signals, but in differing relative amplitude, are decoded with at least one auxiliary channel. The auxiliary channels have the source signals encoded therein with amplitude and phase relations differently indicative of source directions, and the decode of the two mono and stereo compatible channels is combined with the decode of the auxiliary channels to produce presentation signals with sharpened directionality. Also disclosed are limited-frequency auxiliary channels.

Abstract: A method and apparatus is disclosed for reducing distortion between signals that are recorded on a recording medium in a multiple-frequency manner. More specifically, the present invention is directed to reducing or eliminating crosstalk from a main channel signal to a sub-channel signal that is caused by tracing distortion produced in a higher frequency range of the sub-channel signal. The reduction of crosstalk is achieved by reverse compensating a sub-channel signal during recording by an anticipated amount of tracing distortion.