Audio near-distance directional loudspeaker technology for portable multimedia devices

Utilization modes for micro audio near-distance directional loudspeaker in portable multimedia devices are investigated to examine a novel auditory experience. This novel loudspeaker can provide private listening service by emitting the audible sound with high directivity. Two kinds of micro transducer array as the emitter of the directional loudspeaker are presented. One of them is fabricated by MEMS technology and another is assembled by PZT ceramic transducers. The testing results of impedance, frequency response and sound pressure level characteristics are described and compared. It indicates that the performance of PZT ceramic transducer array is better than the MEMS-based transducer array. But the MEMS-based array is the best solution because of the advantage of micro size even though its performance should be further improved and optimized. In the end, A prototype based on PZT ceramic transducer array is constructed for mobile phone usage and its acoustic characteristics are measured. The experiment result indicates the feasibility of utilizing the audio near-distance directional loudspeaker with low power consumption and micro size in portable multimedia devices.