System for improving a spatial effect of stereo sound or encoded sound

A system for improving a spatial effect of stereo sound or encoded sound when producing three dimensional image sound signals from a left stereo channel signal and a right stereo channel signal, comprising

• for each of said left and right stereo channel signals:
• a spatial effect enhancing means for producing a signal for enhancing a spatial effect and a directivity of sound;
• a band enhancing means for generating a signal for enhancing a signal component in a first predetermined frequency range of said stereo channel signal and maintaining a signal component in a second predetermined frequency range of said stereo channel signal;
• and a matrix means for calculating an output signal of said spatial effect enhancing means, an output signal of said band enhancing means and said stereo channel signal in a matrix manner;
• and a gain control means for controlling mutual gain among an output signal of said spatial effect enhancing means, an output signal of said band enhancing means, and said stereo channel signal;
• wherein said spatial effect enhancing means has a characteristic as a high pass filter having an interrupting frequency in a lower frequency range so that a spatial effect and a directivity of sound of a reproduced sound, which is determined by a signal component in a high frequency range, is improved and a signal component of an output signal of said system is kept as that of an original sound signal in a middle frequency range;
• wherein said band enhancing means has a characteristic as a low pass filter having an interrupting frequency in a higher frequency range so that a signal component of output signal of said system is enhanced in a lower frequency range and a signal component of an output signal of said system is kept as that of an original sound signal in a middle frequency range;
• and
• wherein said matrix means has a characteristic in that an output signal of the matrix means provided in a left side stereo channel is a L+βL″−γR′ and an output signal of said matrix means provided in a right side stereo channel is αR+βR″−γL′, where the reference symbols α, β, and γ are factors for conducting in tat a signal component in a low frequency range is passed through said calculations in the matrix means;
• and
• wherein output signals L″ and R″ have a characteristic as a low pass filter, signals L′ and R′ have a characteristic in that a signal component in a high frequency range is passed through, and said factors of α, β, and γ are able to be set in an arbitrary manner.

A system for improving a spatial effect of stereo sound or encoded sound when recording a left stereo channel signal and a right stereo channel signal as three dimensional image sound signals comprising,

• for each of said left and right stereo channel signals, a spatial effect enhancing means for producing a signal for enhancing a spatial effect and a directivity of sound;
• a band enhancing means for generating a signal for enhancing a signal component in a first predetermined frequency range of said stereo channel signal and maintaining a signal component in a second predetermined frequency range of said stereo channel signal;
• and a matrix means for calculating an output signal of said spatial effect enhancing means, an output signal of said band enhancing means and said stereo channel signal in a matrix manner;
• wherein said spatial effect enhancing means has a characteristic as a high pass filter having an interrupting frequency in a lower frequency range so that a spatial effect and a directivity of sound of a reproduced sound, which is determined by a signal component in a high frequency range, is improved and a signal component of an output signal of said system is kept as that of an original sound signal in a middle frequency range;
• wherein said band enhancing means has a characteristic as a low pass filter having an interrupting frequency in a higher frequency range so that a signal component of output signal of said system is enhanced in a lower frequency range and a signal component of an output signal of said system is kept as that of an original sound signal in a middle frequency range;
• and
• wherein said matrix means has a characteristic in that an output signal of the matrix means provided in a left side stereo channel is αL+βL″−γR′ and an output signal of said matrix means provided in a right side stereo channel is αR+R″−γL′, where the reference symbols α, β, and γ are factors for conducting said calculations in the matrix means;
• and
• wherein output signals L″ and R″ have a characteristic in that a signal component in a low frequency range is passed through, signals L″ and R″ have a characteristic in that a signal component in a high frequency range is passed through, and said factors of α, β, and γ are able to be set in an arbitrary manner.