Three months in Beijing ? Micro-perforated absorbers, eigenvalues and other topics

Abstract

In this contribution a personal and scientific report on a three month exchange stay at the Institute of Acoustics in Beijing will be reported. Micro-perforation and low frequencies in small rooms have been the background of an investigation under supervision of Prof. Daa-You Maa in 1999. Maa's ideas from the 1930s about the distribution on Eigenmodes in rooms in combination with micro-perforated absorbers as reference absorbers had been the basis of this work. Abacus and computer calculations as the basis of old/new ideas formed the background of a stay as a student. Even after more than 12 years micro-perforation is part of the daily work as consultant often dealing with new product ideas and developments. The presentation will give a very brief overview on this work that started in Beijing. Furthermore, in remembrance of a once in a life time personal experiences with Prof. Daa-You Maa, his wife and his colleagues will be reported.