Pressure in the mouthpiece, reed opening, and air-flow speed at the reed opening of a clarinet artificially blown.

Abstract

A clarinet with all toneholes closed has been artificially blown and the respective variations of mouthpiece sound pressure, reed opening, velocity of air-flow from the artificial mouth into the instrument, and the pressure in the artificial mouth have been measured. In this paper, the details of these four waveforms are studied and compared for typical examples. Important results are:(1) The reed opening is proportional to the mouth-piece pressure for periodic vibrations, except for the reed-displacement limitations.(2) For nonperiodic vibrations, both the mouthpiece pressure and the reed opening must be observed because their variations are less correlated.(3) The air-flow velocity is roughly proportional to the reed opening when the pressure in the mouthpiece is not so high; however, it decreases with further increase of the mouthpiece-pressure which widens the reed opening. So far as our experimental results are concerned, no positive evidence of the air-flow from the instrument into the artificial mouth has been found.(4) The amplitude of the reed vibrations is limited by the mouth-piece lay or by the artificial lip or by both of these in most vibratory states, while the reed displacement is not restricted in a few states. No rule was found relating the reed-displacement limitation and the blowing parameters (lip-adjustment and blowing pressure).(5) The pressure in the artificial mouth used for these experiments has been isolated from the sounding clarinet system because it has been kept almost constant.