Bolus-red clay and its impact on the frequency spectrum of the sound of wood organ pipes

Abstract

Regarding historical musical instruments it is crucial, after their restoration, to preserve the authenticity of their sound. The present study deals with the influence of the bolus - red clay on the frequency spectrum of the sound of wooden organ pipes. The experiment simulates the application of the restoration process in which they are applied: a primer on the inside walls of the wooden organ. Similar coatings are applied mainly in the restoration of the internal walls of the wooden pipes, that have lost their original acoustic properties. Research has shown the influence of the frequency spectrum of the sound, and thus the resulting sound quality. In each of the cases examined, there has been a significant growth in harmonics, which has had a major impact on the resulting sound quality within the wood register. This result not only opens a debate on the use of certain restoration techniques, but also the question of the impact of the quality of the inner surface of the walls of the pipes on the spectrum of a wooden organ. Further deepening of this knowledge can lead to the conservation of the musically aesthetic quality of historical instruments and thus musical and cultural heritage.