Remember those old nautical folk tales of beautiful sirens luring sailors to meet their sweet below the waves with melodic and mesmerizing serenades? Montreal’s electronic-indie duo Purity Ring has similar tendencies, pulling you into their depths and then devouring you whole. The vocals of Megan James are so sweet and delicate, but with lyrics like “let it seep through your sockets and ears, into your precious ruptured skull,” it’s clear there’s something dark lingering beneath her lacy loops. Word on the street is that other half, instrumentalist Corin Roddick, employs a custom tree-shaped command center that controls both sound and light. Purity Ring’s post-dub and gothic samples have earned their album Belispeak its own genre-name “Witch House,” appropriate considering the twosome’s tunes are captivating and potentially dangerous. Young Magic opens the Ybor date.