Inst. fur Tech. Akust. der TU Berlin, D-1000 Berlin 10, Germany
In his late years Professor Cremer was very interested in violins. After having worked a lot on the vibrations of the strings and the violin body, he wanted to get a better understanding of the radiation properties of violins. As was typical for him, he did not like to use a general numerical method such as the boundary element method; he wanted to find a calculation scheme that does not hide the physics of the problem. So he replaced the radiator by equivalent sources and adjusted their amplitudes so that the radiated sound is approximated to any degree of accuracy. He also showed the close relationship of some aspects of this method to the law of conjugate energies. After Cremer's original publication it turned out that the calculation scheme he proposed can be applied to many other radiators apart from violins. The method and its extension, as well as some examples (boxes of different shape, railway rails, etc.) will be presented in the paper.