Wim Eradus Understanding organ sound better through scientific research
Het ORGEL 98 (2002), nr. 3, 19-28 [summary]

From 16-19 January 2002, a course ‘Organ Acoustics’ was given in the Fraunhofer Institute in Stuttgart. The course was taught by Dr. Judit Angster and her colleagues. Together with her husband, Prof. András Miklós, Angster has been researching the physical aspects of organs for ten years now. Angster is a daughter of the Hungarian organ builder Josef Angster, who lost his company after World War II.

The subjects of the course were: an introduction to musical acoustics; the properties of hearing and the influence of acoustics on organ sound; flow of liquids and gasses and the design of wind supply systems; how labial pipes and reeds function; development of new ways of sound documentation.

Among many other things, it became clear that the tone color of a sound, determined by the amplitudes of its harmonics, is not sufficient for recognition – hearing the attack is essential. Also, it was shown how inharmonic overtones can be ‘removed’ from a pipe’s sound by applying nicks (which does not mean that this would always be the best way).

Another important subject was the relation between the pipe wall and the sound. Many researchers have studied this, and it seems that we have to conclude that, at least with modern pipes, the material of a pipe does not really influence its sound. Another widely spread misconception was also identified as such: pipes on slider chests don’t ‘couple’ their sound via the channels. Interesting, furthermore, was the model Angster developed in order to design wind supply systems.

Judit Angster emphasized frequently that the physical research in her Institute is not done for its own sake, but that it has to be a response to the problems and questions organ builders cope with.