The vast Ponte 25 de Abril in Lisbon can be heard long before you see it—a soft, alluring hum, almost a siren song. Expecting a monumental sound-art installation, Margrit Rieben instead found a bridge that inspired a conceptual choral work voiced by the M+M Chor (36 singers). Each of the 36 voices was recorded separately and without a guide track, producing a slow, organic detuning no unified choir could achieve. As the layers accumulate, the human timbre takes on an uncannily synthetic sheen; overtones bloom like an angelic choir at the horizon, and from apparent monochrome emerges striking complexity. A meditation on resonance, architecture, and the blurred border between the analogue voice and electronic illusion.