Sacha Mullin has spent more than two decades building a musical world that resists easy categorization. His songs move between intimate vocal passages, adventurous harmonies and arrangements that draw from pop, jazz, rock and experimental music. Yet for his fourth album, "Social Touch," the Chicago based singer songwriter is turning toward a more direct pop sound, bringing his distinctive voice and intricate songwriting into sharper focus without abandoning the unpredictability that has defined his work.