With the advent of technology, the sound transduction play an important role in our life. Modern people are more concerned about the tone quality. Now, Mobile phones combined with notebooks, audio electronics, headphones, etc. to make the audio effects better. Although modern technology products tend to light, thin, short, small and easy to carry, the internal component still needs to keep high efficiency. Micro speaker also must keep high tone quality, high sound pressure, high sensitivity, low voltage drives, small structure, high bandwidth, low distortion, low cost, etc. in a limited space.