|Sounding Surfaces and Quality of Tone|
|The bridge and sound quality|
|Varying thickeness of the wood|
|Thickness and internal bracing|
Michael Kasha, a physicist at Florida State University, is a proponent of both varying sound-board thickness and special placement of internal framework in guitar construction. After twenty-five years of research on the action of sound waves inside guitars, he produced an instrument — highly praised by Andres Segovia — with deeper bass, more-even tone, and greater tone-sustaining capability. Segovia said that his Kasha guitar combined the “docility” and “virility” of his favorite instruments and was better than both combined. The Omni article from which this information is taken (May 1990) does not: indicate whether “varying” thickness refers to the usual graduation or to something else — perhaps even the factor of wood density.