PURPOSE: To locate the position of a sound source to a prescribed position at all times even if a head is turned, by detecting the change in a direction through the detection of a magnetic field generated from a reference magnetic field generator and controlling the transmission characteristic of a sound in response to the change in the direction.
CONSTITUTION: An electric signal generated at the reference magnetic field signal generator 11 flows in a solenoid or loop coil 12 and generates a reference magnetic field HO near the head of a listener 2. When the listener 2 turns the head by an angle of θ, an output of a detector 13 is fluctuated, the rotating angle is detected 14 and a control signal is outputted. The acoustic signal applied to an input terminal 15 is added with a time difference to left and right ears with a control signal from the turning angle detecting section 14 at a both- ear time difference adjusting section 17 via a reference direction transfer function generating section 16, weighted with the absolute value of the transfer function at a real transfer function adjusting section 18 and drives a headphone drive section 19. Thus, even if the head of the listner is turned, the sound source is located to the prescribed position at all times.
KIKUCHI YOSHINOBU
GOTOU TOSHIYUKI
