The influence of formants and noise parts on the perceived typicality of woodwind soundsMichael Oehler; Marco Lehmann; Christoph Reuter
The aim of the presented study is to investigate the role of formants and noise parts (e.g. breath noise, air flow) of several woodwind sounds with respect to the perceived typicality of the instrument sounds. In concordance with the results of Reuter (1995, 1996) it is supposed that formants play a dominant role, if the fundamental frequency stays below the first formant area, whereas noise parts become more important, when the fundamental frequency exceeds the region of the first formant. By means of the currently developed analysis software Jaco Visual Signal (by Herbert Griebel with special functions for the Musicological Institute of the University of Vienna), recorded woodwind sounds could be precisely decomposed into a priori specified spectral parts. Clarinet, flute, oboe and bassoon sounds with deleted formant areas, deleted noise parts and a combination of both deletions as well as the inverse versions (only the extracted formant areas etc.) were produced in different registers and used as stimuli in a listening experiment. Subjects were presented with the original instrument sounds and subsequently judged the similarity as well as the naturalness of the modified and original stimuli. Although the conditions were rated slightly different in dependence of the specific instrument, the overall results seem to support the hypothesis. At the same time the described corpus of stimuli is used in neuropsychological timbre experiments (MEG) that, in a further step, will be interrelated with the results of the presented study. Furthermore future experiments may additionally include the phase parameter, in order to correlate the psychological results with current research in the field of digital pulse forming as an explanation for the sound production of wind instruments.