One of my favorite sound when I visited Buddhist temples in Japan is the sound of the giant bells, often called bonshō (or tsurigane or ogane). With the sound wave character that tends to be more of a sinus wave with longer sustain, the sound of this bell feels highly meditative and spiritual. If listened closely, the sound will reach deep into souls. I remember the first time I listened to the bonsho in a temple in Tsui, Awajishima 4 years ago. It was sunset, the sky was getting dark. It was such a magical and spiritual experience.
This record is a sound of one of the bonsho in Yamadera temple located in Yamagata prefecture. This bell’s diameter is not too wide, only for about 30 centimeter which causes less low tone frequency. This fundamental frequency is around 480Hz with a harmonic series frequency which is dominant around 600Hz. Far compared to the larger bonsho (with more than 1 meter of diameter) which can reach around 100Hz of frequency.
Discussing about Japanese’s bell tradition can be a long story. You might have seen it in movies, when monks swings wood to beat the Bonshō. A typical Japanese scene. Bonshō has become a strong part in the spiritual and philosophical part of the Japanese’s lives. Historically, the bell traditions in temples of Japan was brought from China through Korean seas along with the propagation of the Buddhist religion in Japan around the 6th century BC. There has been numerous researches done about bonsho written by academics historically, related to the Buddhist values, and also from the acoustics of bells which is included in physics of sound’s realm. For example from engineer Onozuka Masakazu’s research which focuses on the frequency aspect, shape of soundwaves, organology, and tsurigane’s sound coverage.
Back to the sound record of this bell in Yamadera. Listen to the quality of sound during the first (attack) toll, then resonates (sustain), and lastly that noise lasts for a long period of time until slowly decay. In Japan, all three occurrences of this bonshō has their own terms such as atari, oshi, and okuri. According to the reference I studied, bonsho crafters will work hard to create a high quality sound, just like gamelan crafters who are sensitive over resonance and the instrument’s sound quality they made. If examined further, the length of toll of Yamadera bell can last for more than a minute. Just listen to it. Such an incredible physical acoustic phenomenon. The metal material produced from the mixture of copper and tin steadily vibrates causing a lengthy sound. Isn’t that beautiful? A perfect work of art coming from bonsho crafters. The result of monumental human culture for thousands of years.