Patent ID: 8442237

Claim:
A stereo sound generation apparatus to reproduce multi-channel audio input signals as two-channel output signals, the apparatus comprising: a decimation unit configured to decimate low frequency components of two-channel audio input signals from among the multi-channel audio input signals; a preprocessing filter unit to reduce a correlation between the two-channel audio signals output from the decimation unit and to generate a presence perception; a virtual speaker filter unit to convert the two-channel audio signals output from the preprocessing filter unit into a virtual sound source at a predetermined position; a signal correction filter unit to correct a signal characteristic between remaining ones of the multi-channel audio input signals excluding the two-channel audio input signals and the two-channel audio signals output from the virtual speaker filter unit; and an addition unit configured to add signals to be output to a first channel from among the multi-channel audio signals output from the virtual speaker filter unit and the signal correction filter unit, and to add signals to be output to a second channel from among the multi-channel audio signals output from the virtual speaker filter unit and the signal correction filter unit, wherein the preprocessing filter unit comprises: a first delay unit to delay a first channel audio signal from among the two-channel audio input signals for a first time period; a second delay unit to delay a second channel audio signal from among the two-channel audio input signals for a second time period; a third delay unit to delay the first channel audio signal from among the two-channel audio input signals for a third time period; a fourth delay unit to delay the second channel audio signal from among the two-channel audio input signals for a fourth time period; a first gain unit to adjust an output gain of the third delay unit; a second gain unit to adjust an output gain of the fourth delay unit; a first addition unit to add an output of the first delay unit and an output of the second gain unit; and a second addition unit to add an output of the second delay unit and an output of the first gain unit.