In one embodiment, a sound image is generated by applying first and second copies of a first input audio signal to first and second audio channels, respectively, to generate first and second output audio signals for the sound image. The optical disk drive module includes a chassis module and a drive carrier. A machining-energy adjusting unit adjusts machining energy generated by the main-discharge voltage pulse based on a discharge position determined before applying the main-discharge voltage pulse, and reflects a result of the adjustment on the generation of an electric discharge by feeding the result to the discharge-generation control unit.