バズーンにおけるリードの振動とボーカル入口音圧

抄録

Dynamic properties of the artificially blown bassoon have been studied by simultaneous observations of the reed vibration and the sound pressure variation at the bocal entrance, the former being measured by an optical method and the latter by a probe microphone. It has been found that (a) the waveform of the reed vibration is almost the same as that of pressure variation and the phase of both vibrations coincide well with each other ; (b) the waveform of the reed vibration is peculiar to the bassoon especially in lower tones, i. e. , the reed closes completely for a short time once in a cycle and opens during the rest of the cycle to its full extent, with small vibrations being superposed ; (c) features of waveforms of the above-mentioned small vibration depends on the tone blown but not on the individuality of the reed ; (d) spectra of the reed vibration are not of the form of sinc function in spite of the sharp pulses repeated in the reed vibration ; (e) the first formant is obtained at about 200 Hz for the sound pressure at the bocal entrance, but that of the radiated sound pressure is found at about 500 Hz. Reed vibrations in the played bassoon observed in the player's mouth by an another optical method are also described.