Patent attributes
An acoustic apparatus comprises an attenuator for attenuating a first audio signal to produce a second audio signal, a low pass filter for reducing high frequency components of the second audio signal to produce a third audio signal, a differential amplifier operative to produce a fourth audio signal corresponding to a difference between the first and third audio signals, and a speaker supplied with the fourth audio signal obtained from the differential amplifier, wherein a cutoff frequency of the low pass filter is selected to be not lower than 2 kHz and not higher than 6 kHz and attenuation of the first audio signal in the attenuator is so selected that a listener is able to recognize a virtual sound source position in front of and at a level higher than an actual position of the speaker.
