Patent ID: 7191022

Claim:
An on-vehicle sound-amplification apparatus, comprising: a dipole sound source provided in a vicinity of a position of a passenger wherein at least one acoustic radiation axis thereof is directed outwardly from a vehicle interior; and signal processing means for amplifying an acoustic signal and then inputting an output thereof to the dipole sound source; and a non-directional sound source provided in a vicinity of a center of the dipole sound source wherein an acoustic radiation thereof is driven to have an inverted phase from that of the acoustic radiation of the dipole sound source which is directed into the vehicle interior wherein the dipole sound source includes at least two loudspeakers wherein the at least two loudspeakers are arranged so that respective acoustic radiation planes thereof are directed opposite to each other; and the signal processing means variably controls a phase of an input to at least one of the loudspeakers included in the dipole sound source, wherein the on-vehicle sound-amplification apparatus is located outside the vehicle interior, and wherein the combination of the dipole sound source, the non-directional sound source and the signal processing means produce a radiated sound where substantially no direct sound reaches a location in the vicinity of a position of a passenger.