Objective evaluation of the sound quality at the Faculty of Acoustics Design of Kyushu University

“Measurement and analysis of the acoustic and physical characteristics of speakers”


図のように、材質を変えることで周波数特性が変化し、陶器製筐体の周波数特性を制御できることが明らかとなった。更に、周波数特性が規定のエンクロージャーを使った場合よりもややフラットであり、加えて低域と比べて広域での出力が3dBから5dB大きく、高性能であるといった特徴があった。 オーディオの専門家約100人に主観評価していただいた結果、どのスピーカー電子部品との組み合わせでも、立体感のある密度の濃い音質で、中高音が澄み切っている。イベントスペース等の広い空間では低音が少し弱いが、スピーカーの設置場所の調整で低音もしっかり出る。

sound quality evaluation

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.

一般の土 信楽の土断面
Cross-section of Shigaraki clay, a general-use clay

Cross-section of Koishiwara clay



Sound reflection and absorption properties

General-use clays, such as Shigaraki clay, are usually soft and porous. In contrast, Koishiwara clay is dense and has hard and soft parts, which render the ability to reflect and absorb sound.


Audio house


To protect the originality of the production area, it is crucial to preserve the natural surroundings and transfer the blessings directly into the artwork as efficiently as possible. We never know what the future needs. However, organic products that are elaborately devised by skillful craftsmen may bring happiness to others in the future. After venturing into the sound industry by making speakers and met many people, I could see several ways to the future. I believe that more people will be happy through the creation of new things, and I can expand my dreams by finding many ways.
Second Hekizan Onimaru