A method for sharing a common computing system among multiple users is disclosed. A speaker driving apparatus supplies electric power to a speaker apparatus, acquires information about an electroacoustic characteristic and maximum input electric power of each speaker apparatus from the speaker apparatus, and executes characteristic correction and output electric power restriction according to the information. The resist portion remaining at the interface, after removal of the exposed region, provides a basis for a chemical epitaxy template. For each given mode determined to be \u201coff\u201d, the control panel places each interface configured with the given mode in the second state.