When Pharoah Sanders puts his lips to his tenor saxophone, it’s as if the sky opens up. Sounds rain down in a sparkling shimmer, but the Arkansas native isn’t a mere speed demon. His entrancing flurries of notes are arrayed in glorious patterns, like flocks of birds taking flight against a blank sky. Sanders is a free-jazz icon, first achieving some recognition with Sun Ra in New York before he really came into his own while collaborating with John Coltrane on a series of landmark concerts and recordings in the mid-1960s. As leader of his own bands, Sanders has incorporated African grooves and R&B influences and experimented with such forceful musicians as Bill Laswell and former PiL bassist Jah Wobble. In recent years, he’s been stretching out locally with bop pianist Harold Mabern’s group. Also Saturday-Sunday, Jan. 7-8.