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Aim 2

The second aim was to review acoustic pulse reflectometry as a means of measuring the properties of brass musical instruments, and to perform experiments to give examples of its use.

The theory behind acoustic pulse reflectometry has been reviewed. This included the calculation of the input impedance and bore profile from the input impulse response. An existing practical system used for the measurement of the input impulse response of brass instruments was then set out. Measurements of the input impulse response, input impedance and bore profile were carried out on a test object consisting of two cylindrical sections. Because the actual bore profile was well known, the accuracy of the of the layer-peeling algorithm was readily quantified to be around 0.1mm for this object. Also, the input impedance was compared with theoretical calculations using the multimodal theory for both the stepped tube test object and the bell section of a trumpet.



Jonathan Kemp 2003-03-24