According to one embodiment, a light-emitting device includes a ceramic substrate, a plurality of light-emitting elements, and pressure member. The RRAM structure includes a bottom electrode on a substrate; a resistive material layer on the bottom electrode, the resistive material layer having filament features with a filament ratio greater than about 0. Left and right filters respectively filter audio signals of left and right channels according to the acoustic transfer characteristics loaded from the database. The look-up table may select one of a plurality of scaling factors based upon the index.