Understanding organ sound better through scientific research by Wim Eradus

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 hiscompany after World War II.

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

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

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

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