At other points, the melted murmurs and shimmered syllables feel soothing and psalm-like, as though the girl’s ghost is mourning herself. In places, the young woman’s voice flickers and trembles with playful delight, sounding impossibly alive. Recorded in 1978 but released for the first time this year, the piece is woven entirely from the voice of Ferreyra’s niece Mercedes Cornu, who died in a car accident prior to its composition. Argentine composer Beatriz Ferreyra is renowned for the disorienting spatiality and shape-shifting abstraction of her electronic and tape-based work, but it’s the human scale and raw intimacy of “Echos” that startle.