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Communication Acoustics Laboratory Heads for Wuhan to Appraise the Olympic Copper Bell

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(From Jinqiu Sang of Communication Acoustics Laboratory)  Two graduate students from Communication Acoustics Laboratory headed for Wuhan to appraise the Olympic Copper Bell on December 24th, 2007. They tested the acoustic characteristics of Olympic Copper Bell in a processing workshop of Wuhan Heavy Industry Casting and Forging Corporation. This bell has been named as the Olympic Bell by the Beijing Organizing Committee. It is to be placed at the junction of Beijing middle axis and Olympic Village, which has a far-reaching impact. During the day, several experts on foundry, acoustics, musical instruments, public art and traditional craftwork were invited together to appraise the Olympic Bell from different angles. They measured the Olympic Bell through several tests in the workshop and finally agreed upon the evaluation of the Olympic Bell at the appraisal meeting.

The Olympic Bell is 2.9 meters high. The diameter of the bottom of the Bell is 2.008 meters. It weighs 8 tons. From top to bottom, the structure is: Pu Lao is the double coiled dragon arching the bead; the middle of the Bell's top is a hole called Heaven Door which is 10 centimeters in diameter. The bell's shoulder is a relievo made up of five peace doves and a circle of olive branches. The top strip is made up of three decorated lines. Top Palace and Down Palace are layouts of Nine Palace. The inscription of the bell is a poem named the Olympic Poem. The poem is written in 2008 characters by a famous writer Jinling Wang in China. The bell's dress has a knocking spot, Bell Sun and Bell Moon. The bottom of the Bell is carved with pictures of seas and mountains.   

The copper bell is different from those traditional ones from Tang, Ming and Qing Dynasty in the structure design. Above the waist of the bell, the volume is convergent inwards till the waist. While below the bell's waist, the volume is outspread. At the end of the bell, the proportion of the largest diameter of the bell to the diameter of the bell's waist is around 1:0.6. Compared with conventional bells of the same quality of materials, the volume is smaller. As a result, the basic frequency and subjective pitch of the Bell are elevated.

The results of acoustic measurement are satisfying. The pitches in the frequency spectrum are harmonic. The main pitch is 62.7 Hz which is near standard musical pitch C2:64Hz, which sounds clear and beautiful. The beats in the time domain are obvious and the delay time is rather long. The Bell sends out sounds of nature as soon as it is knocked. The frequencies of the bell are abundant and the attenuation of the bell is slow. In a word, the bell sounds as the effect of thunder, which is reverberant, loud and perfect.  

The Olympic Bell is creative and beautiful. It is founded in an exquisite way. Its loudness is high. Its tones are beautiful and touching. The bell is innovative and of high technique, which is a perfect outcome of the combination of High-tech Olympics and People's Olympics.

Figure 1 Blueprint of the Olympic Bell

Figure 2 Picture of the Olympic Bell


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