Acoustic image creation system and program therefor

A computer-readable storage medium, having embodied thereon an acoustic image creation program for creating a left-right pair of surround sound image signals, from audio input signals containing a left signal, a right signal, a left-rear signal, and a right-rear signal, wherein the program, when executed, causes a computer to perform the steps of:

• a left-rear-localization-process step of creating a left-rear localization signal, where said creating a left-rear localization signal includes left-signal summing together the left signal and the left-rear signal into a left summation result and performing a first left rear-localization-filtering-process on the left summation result to create a first left rear-localization-filtering-process result;
• a right-rear-localization-process step of creating a right-rear localization signal, where said creating a right-rear localization signal includes right-signal summing together the right signal and the right-rear signal into a right summation result and performing a first right rear-localization-filtering-process on the right summation result to create a first right rear-localization-filtering-process result;
• and
• an acoustic image creation step of creating the surround sound image signals, from the left signal, the right signal, the left-rear localization signal, and the right-rear localization signal.

An acoustic image creation method for creating a left-right pair of surround sound image signals, from audio input signals containing a left signal, a right signal, a left-rear signal, and a right-rear signal, the method comprising the steps of:

• a left-rear-localization-process step of creating a left-rear localization signal, where said creating a left-rear localization signal includes left-signal summing together the left signal and the left-rear signal into a left summation result and performing a first left rear-localization-filtering-process on the left summation result to create a first left rear-localization-filtering-process result;
• a right-rear-localization-process step of creating a right-rear localization signal, where said creating a right-rear localization signal includes right-signal summing together the right signal and the right-rear signal into a right summation result and performing a first right rear-localization-filtering-process on the right summation result to create a first right rear-localization-filtering-process result;
• and
• an acoustic image creation step of creating the surround sound image signals, from the left signal, the right signal, the left-rear localization signal, and the right-rear localization signal.