Consultation des notices

According to an expert organ-builder (or voicer), the onomatopoeia 'hiss' must be distinguished from the more common term "chiff" in order to describe the characteristic bursts of noise occurring during the transient of many flue organ pipes. These sounds can be adjusted and aligned to a certain aesthetic but many organ experts do not yet discuss this matter much. In this study, three pipes of the same pitch were recorded. Two listening tests were administrated via a computer (1) and results are presented. The first test explores the faculty of musically trained listeners to separate harmonics and noise parts. The second test focuses on the perception of ‘hiss’. An attempt is made to match the results of the second test with a time-frequency analysis of the recorded sounds. The noise/harmonic separation task was successful for a large number of subjects supporting the hypothesis of a natural perceptual difference between the noise bursts and the concomitant harmonic set-up. To differentiate and identify 'hiss' sounds is a much more elaborated task which requires experience. Still there is a clear correspondence between the answers of the subjects and of the voicer. Some components of the starting transient are showed to play a main role in the perception of ‘hiss’.