The Monk by the Sea is the name under which Ivan Ujevic of Zagreb, Croatia, records lush ambient music, often guitar-based. Presumably the “sea” in question is the Adriatic, which separates Croatia from Italy. In a new track titled “Lost at Sea,” the Monk by the Sea ventures into a spectral zone, a purely imaginary space, one that feels more celestial than aquatic. When the piece first opens, the familiar pluck of an electric guitar and the effects of backward-masking — already a nostalgic technological touch when employed by rock musicians in the 1960s, and these days doubly so — are easily recognizable. Yet as the work moves forward, those sounds get lost in — more to the point, those sounds expand to become — a vast shuddering spectacle, a voluminous shimmer that drones on like the sonic equivalent of the horizon.