JPS54123902A - Stereo reproducer - Google Patents

Abstract

PURPOSE:To improve spreading feel and depth feel of listening sounds by adding and mixing left and right channel signals and making their specified regulation of delay, phase shift and level thereby forming artificial indirect sounds. CONSTITUTION:The mixed signal of left and right channels by a mixer 1 is delayed for the time tau1 corresponding to the path difference between the distance (a) from the listening point P up to the sound image localization position I and the distance (b) from the position I up to the reflection point of the wall B by a delay circuit 2 and is then made to the artificial indirect sound signals of direction -xsi1 of sound pressures PL, PR for the left and right ears of th listener of a phase difference theta and amplitude ratio X based on formulas I, II by phase shifters 3, 4 and level setters 5, 6. At the same time, the artificial indirect sound signals from the direction xsi2 are formed in the similar manner and when these artificial indirect sounds and the left and right channel signals are synthesized in adders 14, 15 and the synthesized signals are applied to speakers, these are received as the sound image of the fixed point further from the point P and those corresponding to the reflected sounds through reflection of the wall at a far distance, thus even in a narrow room the listened sounds have increased spreading and depth feel. Here, gamma denotes the attenuation constant by head diffraction and PO the reference sound pressure of the indirect sounds.