A transducer comprising an acoustic energy generating means and a resonator. The electrode layers are planarized to obtain an extremely planar surface. The Entertainment System including a database subsystem, a registration subsystem, a server subsystem, and a virtual world providing subsystem. A second intermediate representation is generated responsive to the application of the at least one optimization technique to the first intermediate representation. The auxiliary air duct is fixed on the bottom of the main air duct, and is accommodated in the first air duct area, so as to further isolate a second air duct area in communication with the air inlet it the first air duct area. Because the fastening blocks are not easily deformed, the card connector can be firmly fixed in the circuit board and avoids being slanted downward in use.