As shown in the figure, it is clear that changing the material changes the frequency characteristics, and it is possible to control the frequency characteristic of the ceramic case. Also, the frequency characteristics are slightly more flat when the specified enclosure is used, and the output was 3dB to 5dB louder in a wide area when compared to the low-frequency range, the characteristic of a high-performing speaker. The result of subjective evaluations by around 100 audio experts showed that combining this item with any speaker electronic components results in robust and dense sound quality with clear mid- and high-pitched sounds. Although the bass sounds a little weak in a large space such as an event space, it can be heard well by adjusting the location of the speaker.