| 摘要 |
PROBLEM TO BE SOLVED: To optimize the hearing state of an occupant by detecting a position of each occupant, determining a volume setting value to each speaker on the basis of this position of each occupant, and controlling the sound volume so as to be reached to the volume setting value. SOLUTION: As for a sensitive differential in the output volume of a speaker, if it is compared with a speaker S1 having correlation to a distance between speaker and occupant, sound volume of a speaker S2 - a driver at a point (d) perceives - is d1/d2 times over the output volume of the speaker S1 to be perceived. Supposing that each output volume of speakers S1 to S4 is set to be M1 to M4 respectively, the driver at the point (d) feels that it is M1=M2=M3=M4 at a time when the output volume of these speakers S1 to S4 is in relation to M2=γM1, M3=βM1, M4=αM1, (whereα=d4/d1,β=d3/d1,γ=d2/d1). Accordingly, with the output volume of these speakers S1 to S4 set up, the driver at the point (d) feels that each speaker is the same volume, so that a hearing state is thus optimized.
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