The Bulgarian Women’s Choir introduced many Westerners to the haunting chorales of their Eastern European nation. Several other ensembles have followed in their path. The London-based Perunika group, a trio of women of Macedonian descent (the region’s borders are porous), are resolutely traditional despite their previous background in rock and classical. The result is the opposite of the junky “fusions” prevalent in world music. Weaving spooky tapestries with voice and the occasional accompaniment of woodwinds, the trio sings timeless songs associated with changing seasons, the rites of fertility and the spirituality of Eastern Orthodoxy. The heartbreak and yearning of their music threatens to burst the bonds of the material world.