“For Voice” by artist Lydia Ourahmane was created in collaboration with her sister, composer and musician Sarah Ourahmane. Written for two visually impaired female singers, the composition unfolds across the triangular gallery space of the Galeria Municipal do Porto. Barely visible yet perceptible to touch, the score is embedded directly into the gallery walls. The piece responds to and studies the architecture: its structure is entirely determined by the gallery’s dimensions. When activated, each singer traces the Braille score along the walls, moving through the space as the composition unfolds.

In Braille musical notation, the six-dot cell conveys both pitch and rhythm, alongside the key and octave in which the composition is written. The score appears as a continuous line in which notes, durations, octave registers, ligatures, pauses, and interpretive instructions follow one another sequentially. By reducing ornamental markings and instructions, the piece invites each singer to bring her own interpretive logic to the phrasing. They must therefore memorize the distinct elements of the score and reconstruct them via performance, introducing an expanded potential for variation and entropy, as each performer’s method shapes the spatial choreography of the work.

Following the performance, a kinetic audio system installed on a linear rail replays a recording through two speakers. In the darkened space, the illuminated speakers move through the gallery, echoing the cadence and trajectories of the singers, translating the score in their absence.

At the weekend marking the end of the exhibition, singers Cristina Afonso and Joana Rita Santos will return to the Porto Municipal Gallery for a final live performance of “For Voice”.