A speaker device for improving mid/high-range frequencies includes a magnetic base, a frame annularly mounted to the magnetic base, a cone mounted to an inner side of the frame, a voice coil mounted to the cone and suspended in a gap of the magnetic base, and a deadening phase plug mounted on a central portion of the magnetic base. The magnetic base includes a T-iron, a magnet, and a pole plate. The deadening phase plug is made of a sound-absorbing material for absorbing and eliminating sound waves generated by the voice coil and the cone.