Originally posted by sigmonkey:
quote:
Cu tube and glass bottle thing
Not sure if I understand your post, but...
Copper (pipe) slide and glass (beer/booze bottle neck, or "pill bottle" ) used as a slide to play (mostly played in open tuning) where the tuning is a major chord (typically), so the slide closes the bar chord on the fret and permits a constant "base line" and then fingered or multiple strings with the slide create melody lines.
The result is the "illusion" of multiple parts played on a single guitar, that often required two or more people to play a similar composition.
Similar to various finger picking techniques that also resulted in a rich composition by a single player on a single instrument that "sound/appeared" to be more than one player. (as Robert Johnson's finger picking often came across as three players).