A little left field,perhaps,but this relates in a post modern yet anciently rooted kinda way:
Acool bit of pop,or should that be rock? Culture stuff,re the musical/acoustic applications of trig,oh and of it's magick too of course, lol...
Devil's Tritone and the diminished fifth:
"While playing shows in England in 1969, the band discovered they were being mistaken for another English group named Earth, and decided to again change their name. A cinema across the street from the band's rehearsal room was showing the 1963 Boris Karloff horror film Black Sabbath directed by Mario Bava.
While watching people line up to see the film Butler noted that it was "strange that people spend so much money to see scary movies." Following that, Osbourne and Butler wrote the lyrics for a song called "Black Sabbath", which was inspired by the work of occult writer Dennis Wheatley along with a vision that Butler had of a black silhouetted figure standing at the foot of his bed.
Making use of the musical tritone, also known as "The Devil's Interval", the song's ominous sound and dark lyrics pushed the band in a darker direction', a stark contrast to the popular music of the late 1960s which was dominated by flower power,folk music and hippie culture. Judas Priest frontman Rob Halford has called the track "probably the most evil song ever written".
Inspired by the new sound, the band changed their name to Black Sabbath in August 1969 and made the decision to focus on writing similar material in an attempt to create the musical equivalent of horror films."