Found primarily in Morocco, Gnawa is a passionate, devotional fusion of Sufi/Berber/sub-Saharan musics in which musicians, often appearing as if in a trance, engage in intense, lengthy (up to hours-long) descriptions of the spirits. Gnawa compositions consist of a single phrase or just a few lines that musicians repeat over and over. The rhythms are complicated and the time signatures shift readily between 2/4, 6/8 and 12/8. Watch gnawa superstar Hassan Hakmoun rock out on the sintir.
About Gnawa music:
Wikipedia’s Gnawa overview | Hassan Hakmoun demonstrating the multi-tempo Gnawa footdance