William Peter Pester.
"The Hermit of Palm Springs"
Playing unidentified Knutsen guitar. 1917(!)

Steel Guitar is a microtonal instrument...

Here's an interesting ( if heavy-going ) paper by Akine Honingh which really delves into the theory and science behind the relationships between pitches.
Although it doesn't really explore the influence that cultural differences have on the perception and organisation of pitch into scalar patterns it does give insight into the workings and reasoning behind Equal Temperament and Just Intonation, plus the title sounds kinda cool like something from Gurdjieff's "All & Everything".
The Origin and Well-Formedness of Tonal Pitch Structures

Another nice read...about rhythm...
The Role of Subvocalization in Rehearsal and Maintenance of Rhythmic Patterns.