Patent ID: 9118997
Filing Date: 2015-08-25
Classification: H04R

Abstract:
1. A speaker device comprising: a line array speaker that includes a plurality of speakers arranged on a same plane at predetermined intervals; an IIR filter that is adapted to control an amplitude characteristic of a digital sound signal; a plurality of FIR filters that correspond to said speakers and each delay common said digital sound signal input through said IIR filter; and a plurality of D/A converters that each convert said delayed digital sound signal to an analog sound signal, wherein said FIR filters delay said digital sound signal so as to increase a ratio of a delay time difference to the arrangement interval between adjacent speakers toward one end of said line array speaker; and said FIR filters compensate for a phase characteristic of said IIR filter and delay said digital sound signal such that a minimum value among the delay time differences between the adjacent speakers becomes less than a sampling period of said digital sound signal, wherein filter coefficients for said FIR filters are obtained by adding a common shift delay time for each of said FIR filters to values obtained by performing an inverse Fourier transform of frequency characteristics determined by turning said phase characteristic of said IIR filter upside down and rotating said phase characteristic of said IIR filter by a predetermined angle.