Improving Real-Time Pedal Steel Guitar Audio Synthesis through Physical Modeling

Abstract

The pedal steel guitar (PSG) is a common instrument in American country music, with an inseparable history and present steeped in country, but recently, it has become increasingly adopted in other genres and spaces outside of the American countryside because of the instrument's unique color and capabilities for expression. The aim of this thesis is to analyze the nature of the pedal steel sound and the methods for re-synthesizing it to improve a pedal steel physical model, specifically the one which runs on the embedded hardware of the Electrosteel instrument, to allow for real-time performance. The creation of the Electrosteel by Jeff Snyder, Davis Polito and Matthew Wang, was to allow PSG players to interface and perform with a synthesizer through the means of the pedal steel's distinguishable expression and timbre. In this way, players can not only transfer their techniques to new sonic timbres and textures, but using a realistic physical model, also extend the sound of the PSG to create near-unreproducible sounds otherwise on physical pedal steels. Through the methods provided in this thesis, an investigation was taken into how the physical model for string propagation works in this low-computation environment to explain what parts from electric guitar modeling is applicable to the physical model of the PSG and what parts of this model affect tone and timbre. This thesis also clarifies some of what can be quantified with the sound of the pedal steel, and how one can improve the physical model further, as well as what improvements were made through this work, all in an effort to enable future live-session usage and replacement for the PSG, particularly in use cases where the portability of the Electrosteel matters (i.e touring). Through this work, three different methods were used to model the decay of sounds, some of which were taken from measurements of two types of PSG with different characteristics, and other models were investigated based on electric guitar models as well. These models were iterated on and simulate the effects of an electromagnetic pickup based both on the physical PSG's electrical circuits, and from recordings of the PSGs.