Analysis and Synthesis of the Chiff of Organ Pipes

Tutor: Stefan Goetze
Type of Thesis: Diplomarbeit (Dipl.)
date of end: 07/2007
Student: Raphael Knoop
Status: finished
ANT-shelfmark: D-07/07-1
Abstract: The sampling technique is widely used in digital church organs to
reproduce the sound of a classical pipe organ and makes it possible to
build digital church organs with a very natural sound. For the human
hearing the first few milliseconds of a sound - the attack section - are
very important to identify the character of the sound. In case of an
organ pipe in the attack section the partial tones of the sound are
coming in but also some noise caused by turbulent streaming which
decreases over time. Organ builders call this 'the chiff' of the pipe.
While the chiff has a very dynamic and transient behaviour and can be
influenced by the organ player, with the sampling technique only a
certain situation can be reproduced. The aim of the diploma thesis is to
find an algorithm which uses signal processing techniques to decompose
the original sample of an organ pipe into the partial tones and the
noise with repsect to the transient character of the chiff. Therefore
several techniques have to be researched. With the results of the signal
decomposition a new technique should be developed which makes it
possible to reproduced the sound of an organ pipe and the chiff with
respect to a mathematical description, physical properties and a
realistic interaction with the organ player.
Last change on 30.04.2008 by S. Goetze
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