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Contents
List of Figures
List of Tables
Introduction to the study of wind instrument acoustics
Background
Acoustic resonance
Exciting the air column
Input impedance
Input impedance measurement techniques
Frequency domain measurement
Acoustic pulse reflectometry
Calculation of the input impedance
Multimodal propagation
Aims and outline of thesis
Multimodal propagation in acoustic horns
Introduction
Plane waves in a uniform section of tube
Plane waves at a change in cross-section
Multimodal equations in a uniform wave-guide
Solutions for a cylinder
Solutions for a uniform rectangular duct
Multimodal equations at a discontinuity
Solutions for circular cross-section
Solutions for rectangular cross-section
Method for calculation of input impedance
Projection across a discontinuity
Projection along a cylinder
Method for calculation of pressure field
Radiation impedance
Introduction
Ideal open end condition
The piston approximation
Pressure radiation from a piston terminated in an infinite baffle
Pressure radiation from a duct terminated in an infinite baffle
Multimodal radiation impedance of a duct terminated in an infinite baffle
Multimodal radiation impedance of a cylindrical duct terminated in an infinite baffle
Analysis
Results
Multimodal radiation impedance of a rectangular duct terminated in an infinite baffle
Analysis
Results
Numerical implementation of multimodal theory
Review of input impedance method
The radiation impedance matrix
Projecting the impedance matrix
Numerical implementation
Results for a trumpet section
Acoustic pulse reflectometry
Introduction
Input impulse response
Input impedance from the input impulse response
Layer peeling bore reconstruction
Numerical implementation issues
Losses
Apparatus
Experimental measurement of the input impulse response
Deconvolution
Experimental measurement of the input impedance
DC offset
Experimental measurement of the bore profile
Multimodal reflections
Introduction
Multimodal reflectance matrix
Multimodal reflectance of a single discontinuity
Multimodal input impulse response
Issues in multimodal bore reconstruction
Multimodal scattering matrix
Iteration method with multimodal control
Improvements to pulse reflectometry
Introduction
The virtual DC tube method
Measuring longer objects
Source reflection cancellation method
Results
Maximum length sequences
Generating an MLS sequence
Auto-correlation property of MLS
Extracting the system impulse response from MLS measurement
Acoustic pulse reflectometry measurement with MLS excitation
Conclusions
Achievement of aims
Aim 1
Aim 2
Aim 3
Aim 4
Future work
Properties of Bessel functions
Projection at a discontinuity
General expression
Pressure
Volume velocity
Projection matrix in cylindrical geometry
Inductance method
Bibliography
Jonathan Kemp 2003-03-24