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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.

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.

Important results were obtained by artificial blowings of the reed woodwind instruments: Many states of air column vibrations can be excited under a fixed fingering and a fixed embouchure; these states have their respective regions of blowing pressure in which frequency and waveform of the air column vibration change slightly and continuously as the blowing pressure is varied; a sudden transition from one state to another takes place irreversibly at a blowing pressure, the upper (or lower) boundary of the state, when blowing pressure is increased (or decreased) gradually. It will be presented that the above‐described results are not necessarily valid for a conical brass pipe (0.63 m long), which has the same apex angle as that of the bassoon, blown by the mouthpiece of the soprano saxophone. One of the vibratory states excited has changed to another state without transition. When a cylindrical brass pipe, which has about the same length as that of the clarinet, has been artificially blown with the clarinet mouthpiece, the reed has been easily broken, which has rarely been observed for the clarinet.

The sounding mechanism of a simple clarinetlike system has been investigated experimentally and numerically. The system consists of a cylindrical pipe fitted with the clarinet mouthpiece. By artificial blowing, it produced various periodic and quasiperiodic sounds, among which the lowest pitch was Cs3. In particular, hysteresis of the vibratory state transitions was observed when the flowing pressure was increased and decreased under the same lip adjustment. This was also observed for the artificially blown clarinet. The behavior of the simple system is analyzed numerically by using the Schumacher model [Acustica 48, 71–85 (1981)]. The numerical model is characterized as a double‐delayed feedback system represented by a simple reflection function consisting of two separated narrow Gaussian peaks. One of the peaks is due to the main reflection from the open end of the cylindrical air column, and the other, which introduces a short delay, originates from the inside discontinuity of the mouthpiece. Thi...

The impulse response of an oboe air column was measured by means of the transfer function method. This will be applied to the construction of the model for synthesizing musical sound and to the trouble‐diagnostics of the instrument. Pressures at the two points are simultaneously measured in the cylinder, which is smoothly connected to the tested instrument. A time‐stretched pulse is used, with the property of its phase being proportional to the square of its frequency. The generation of the pulse and the acquisition of the signal are synchronously made under computer control. The received signal is then averaged. The advantages of the method are the following. (1) The frequency responses of the measuring system, which is the sum of those of the transducer, microphone, amplifier, and so on, are compensated at once. (2) The time‐stretching pulse enables one to impress high power to the test object. (3) The averaging attains a high S/N ratio. Results were obtained, with sufficient accuracy, which allows one ...

A new method for speed measurement by correlation techniques is proposed. An image of a rough surface of a moving object is obtained every 1/30 second using an ITV camera with a rotary shutter. The displacement of the object during 1/30 second is estimated from a polarity cross-correlation function between two successive surface images. (1) The speed v to be measured is proportional to the displacement. (2) v = O can be measured. (3) The average length for the computation of correlation function is determined from the measurement accuracy required. The time required for signal processing is less than one field period (1/60 second).

Reed vibrations and pressure variations in the reed have been observed at the same time for the lowest note of a bassoon artificially blown. For comparison, the observations have been performed also for a cone simulating the bassoon and for a bassoon without tone holes. Behaviors of the bassoon and the bassoon-like systems artificially blown are fairly similar and remarkably complicated.

Input impulse responses of several bassoons are presented. The impulse responses are obtained by the inverse Fourier transform of measured input impedances of the bassoons as seen from the bocal entrance. Method of input impedance determination are outlined. Comparison of the impulse responses shows such differences between a particular bas-soon and the others as can be found only by test blowing.

Reed vibrations have been observed for the lowest notes of a bassoon, an oboe, a clarinet, and a soprano saxophone artificially blown. The blowing pressure in the artificial mouth used has been increased from 1.5 k Pa to about 10 kPa (20 kPa for the oboe) and decreased. The relative position and contact pressure between the lips and reeds have been fixed during a cycle of changes in the blowing pressure. Conclusions: (1) Many different modes of very stable periodic vibrations are found even under the same blowing pressure. (2) A slow continuous change in blowing pressure causes a sudden transition from one mode to the next without a change in the lip‐reed relative position; this in turn gives rise to some change in the blowing pressure. (3) Which mode is excited under a given blowing pressure depends on the sequence of the preceding modes. (4) In the bassoon and oboe, not all the transitions are reversible; with blowing pressure being increased and decreased, the sequence of modes encountered exhibits hys...

A new method similar to the stroboscopic observation for measuring the correlation functions and the impulse responses of linear systems is described. The method essentially makes use of a peculiar periodic property of the autocorrelation function of a signal derived from a maximal-length binary shift register sequence which is applied to the input. A quick impulse response can thus be recorded directly on a rather slow pen writing oscillograph with the scale of time magnified by a factor of several thousands. An example of oscillogram showing the response of a sonic system is presented.