Stereophonic phase filter for correcting sound image in sound reproduction system of car, has passing unit including all pass filters of second and first order on channels with phase difference remaining constantly close to specific values

摘要

The filter has a passing unit including all pass filters of order 2 and order 1 on channels having quality coefficients equal to 0.8 and 7 and equal to 2, where the filter maintains a phase difference between right and left channels near to 0 degree in low frequencies. The phase difference abruptly rises to 180 degrees inside a band of width close to or less than one sixth of octave between 45 and 135 degrees at frequency between 80 and 160 Hz. The phase difference between the channels remains constantly close to 180 degrees until the frequency is equal to approximately 500 Hz. An independent claim is also included for a device for broadcasting sound messages in a vehicle.