Abstract
We aimed to develop an easy-to-use artificial larynx with high tone quality. We focused on using a piezo speaker as the sound source because it is small, consumes less power, and is harmless to humans. Conventional piezo speakers are problematic in that they cannot generate enough sounds in the low-frequency range; thus, they cannot be used in artificial larynges. Therefore, we aimed to develop piezo speakers generating enough volume in the low-frequency range. If the resonance frequency of the speaker is lowered, it can easily generate low-pitch sounds. Therefore, we have created new diaphragms with low resonance frequency. Here, we report on the characteristic comparison of this piezo speaker. In fact, we analyzed the optimization of its structure by using finite element method computer simulations and fast Fourier transformation analysis of the generated sounds. By the result of computer simulation, we confirmed that the stiffness of the diaphragm was adjusted, and the resonance frequency was able to be lowered. By the result of analysis of the sound generated by the piezo speaker using the diaphragm, we confirmed that the resonance frequency was able to be lowered too.
