Acoustic documentation of 12 pipe organs and analysis of their plena

Abstract
The method for acoustic measurement and documentation of pipe organs developed in 1991 in VUZORT, Prague enables to describe the sound of all organ pipes and plena measured in situ. The real time measurement and digitalisation of the sampled sound, computation and processing of the amplitude spectrum are possible without necessity of sound recording. Sampling frequencies were adjusted to the stop length and fundamental frequency of the measured tone. The results of factor analysis of the octave spectra of Great organ plenum for 12 instruments are described. The Czech Baroque organs created a distinctive group in 3-dimensional factor space due to their rich harmonic spectra.