Over the years I've published a number of papers and articles on audio topics in various magazines and journals, and most of those are available here.
Another View of TIM
A Fully In-Band Multitone Test for Transient Intermodulation Distortion
Build a High Performance THD Analyzer
Open-Loop Output Impedance and Interface Intermodulation Distortion
Phase Intermodulation Distortion - Instrumentation and Measurements
A MOSFET Power Amplifier with Error Correction