Investigation of the acoustical characteristics of organ pipes in a performing space

Abstract

The acoustical influence of organ pipes on the sound fields within a performing space was investigated. Test specimens with appropriate characteristics were determined after a field survey of various prospect pipes. Laboratory tests using 1:10 scale models were carried out to identify the surface characteristics of an organ's prospect pipes. The absorption, scattering and diffusion coefficients of the prospect pipes were found to range from 0.09 to 0.10, 0.11 to 0.31, and from 0.18 to 0.37, respectively. From the field measurements made in a large concert hall with a pipe organ on the right lateral wall, higher G and LFE4 values were observed at positions nearer the pipe organ. Additionally, a computer simulation was employed to identify the acoustic properties of the pipe organ within a hall. As a result, it was derived that the pipe organ, including the prospect pipes and the organ enclosure had an absorption coefficient of 0.21 with higher absorption at lower frequency bands and an average scattering coefficient of 0.50.