Directivity of a small pipe organ buffet

Abstract

While the radiation pattern of small instruments can be measured in anechoic chambers, it is challenging to study the directivity of large, unmovable instruments such as pipe organs associated with cultural historic sites. The soundfield outside an organ buffet is the result of the convolution of the sound of the pipe with the surrounding scattering system, the enclosing cavity of the instrument, and the apertures between the pipes in the façade of the instrument. The directivity of a small, proxy organ buffet consisting of a plywood enclosure with PVC pipe scatterers was studied in an anechoic chamber using omnidirectional and cylindrical loudspeaker sources. This proxy buffet grants access to modeling parameters such as the pipe spacing and density. These laboratory measurements were then compared to in situ, free-field directivity measurements of the same sources inside a real positive organ buffet of comparable size and shape located inside a church.