terça-feira, 25 de dezembro de 2012




    This thesis presents an interdisciplinary research on reed woodwind instruments and human voice, focusing on acoustical, physiological and perceptual aspects of sound generation.

    The wind instruments studies concentrate on breathing and blowing under realistic conditions and provide a deeper insight on required aerodynamical input parameters. The variation of blowing pressure with loudness and fundamental frequency was measured in professional players of oboe, bassoon, clarinet, and alto saxophone and was found to be quite systematic, though differing between the instruments. Airflow for sustained tones was measured by indirect spirometry, together with blowing pressure and sound pressure level, using extreme reeds, one soft and one hard. Recordings were made in an ordinary room as well as in a calibrated reverberant chamber. Also, tones with an intense vibrato were analysed for the oboe, the saxophone and the bassoon. The results revealed wide variations in blowing pressure, suggesting that a rhythmic modulation of the contraction of expiratory muscles was a main factor, and relatively small variation in fundamental frequency. The players’ perception of self-produced static lung pressures typically used in performances was analysed in a psychophysical experiment, that revealed a quasi-linear relationship between perceived and produced pressures. The respiratory movements during playing were measured by a non-invasive technique, respiratory inductive pletysmography, which offered acceptably reliable data. The results revealed significant participation of the rib cage in all players and also of the abdominal wall in several players. Also, the impact of the continuous changes of O2 and CO2 gases in the pulmonary air exhaled during performance on the fundamental frequency was predicted from theory and compared with experimental data. The effect, smaller than that of temperature variation, still would represent a factor of potential relevance to wind instrument intonation. In addition, the sound production characteristics of a particular type of phonation, perceptually judged as similar to that used in Tibetan chant, were studied by high-speed imaging. Also, it was examined using acoustical and physiological methods. The results revealed a synchronised co-oscillation of the vocal and ventricular folds, which yields a lowering of fundamental frequency due to multiplication of the vocal fold period.


    Keywords: blowing pressures, reed woodwinds, oboe, clarinet, saxophone, bassoon, music performance, respiratory inductive plethysmography, perception of blowing pressure, intonation, aerodynamics, Tibetan chant, ventricular folds, respiratory behaviour, airflow, vibrato, music acoustics, physiology of music.

    ©1998 by Leonardo Fuks



Nenhum comentário:

Postar um comentário