Abstract:
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 to distinguish the shapes of the air column and perceive the differences in the level of the joint.