Nonlinear vibrations in the air column of a clarinet artificially blown

Abstract

A clarinet with all toneholes closed has been blown artificially and the respective variations of mouthpiece sound pressure, reed opening, and volume flow from the artificial mouth into the instrument have been measured. For a fixed lip adjustment (lip–reed contact position and height of the reed opening under lip pressure), several different vibratory states were found over the complete range of the blowing pressure. The states were stable within their respective regions, but sudden transitions took place from one state to the other when the blowing pressure was varied beyond the stable region. Multiple vibratory states were excitable in some ranges of the blowing pressure, the state excited being dependent upon the manner in which the blowing pressure was varied. The experiment was repeated for different lip adjustments. For the examples discussed, the closed tonehole fundamental of this instrument (D3 on the equally tempered scale) was inevitably produced, but other stable vibratory states were also excited. The vibratory states found for the lip adjustments presented were both periodic states emitting tones of pitch D3 or of much higher pitches, and aperiodic states most of which had an attractor of torus T2. At least one state of torus T3 was identified. Excitation regions of these vibratory states are described.