1, floor elevation
1924, Tsinghua University appointed Hai Yan, a teacher of natural science department, and other three people to discuss and solve the acoustic problems of the auditorium. As a math teacher in Tsinghua University Advanced Department, through general observation and empirical analysis, Dr. Haiyan thinks that the right angle of the inner wall of the auditorium is too sharp to transmit sound. Therefore, he initially proposed countermeasures: or "raising the rubber floor to blunt its angle"; Or "hang the ceiling of the auditorium with a cloth curtain to make a circle, and the angle can be increased." What Haiyan and others came up with was only a very rough plan, which did not touch the essence of architectural acoustics.
2. It is the first time to use the theory of architectural acoustics to propose a solution.
From 65438 to 0926, Professor Ye led a research team composed of colleagues from the Department of Physics and experimental assistants at the beginning of its establishment, conducted a comprehensive study on the latest progress of architectural acoustics abroad, roughly grasped the meaning of Sabin formula, and initially realized the influence of large space structure, vocal characteristics, sound field distribution, temperature and other factors on reverberation time. At the same time, Ye Group creatively studied the influence of indoor temperature change on reverberation time, which was not considered by Sabin formula, and completed the measurement of sound absorption capacity of Chinese clothing, which provided important basic parameters for architectural acoustics in China at that time.
Based on the new architectural acoustics theory, Ye's team analyzed the reasons that lead to the difficulty in listening to the audience: the spatial form defect of vault modeling, and too little sound-absorbing materials in the lime brick interior wall directly lead to too long reverberation time. It is pointed out that the most suitable reverberation time of Tsinghua Auditorium is 1.75 seconds, and it is calculated that the sound absorption capacity needs to be supplemented by 470 square meters (window opening), and the dome, four curved surfaces and four walls are the main positions for laying sound absorption materials.
It should be said that Ye Group accurately found out the causes of acoustic problems in Tsinghua Auditorium theoretically, and put forward the solutions to architectural acoustic problems. Although the solution proposed by Ye Group has not been implemented, their theoretical research has enabled the research and practice of architectural acoustics to enter a broader scientific field of vision from Tsinghua University, laying the foundation for the start of modern architectural acoustics in China.
3. Acoustic reconstruction of Tsinghua University's 90th anniversary.
Before the 90th anniversary of 200 1 Tsinghua University, Tsinghua University organized relevant experts to carry out a simple acoustic transformation of the auditorium. At that time, the school decided that the building and decoration of the auditorium could not be moved, so the original curtains were replaced only at the position where the window was opened on the wall. The newly added curtains are thicker and heavier than the original curtains, and the sound absorption coefficient is higher. At the same time, the number of speakers in the original sound reinforcement system is increased, which makes the audience's sound field more uniform.
This renovation has improved the acoustic effect of the hall room to some extent, but it has not fundamentally solved the problem of long reverberation time of architectural acoustics.