As the audience's rustling quietens along with the memories of everyday pulses, ethereal sounds appear. We are at Helsinki's iconic Rock Church, on the eighth night of the biennial Musica nova festival for contemporary music. The Helsinki Chamber Choir sound the first, lingering lines of György Ligeti's Lux Aeterna from the balcony, behind the audience. The peculiar acoustics give the illusion that the choir is hidden in between the crevasses and cracks of the stone wall in front. The listener is surrounded. Marvellously kept together by Nils Schweckendiek, the singers transform the colour of their voices into sine-tones and oboes in a strangely soothing way. This rendition now somewhat more present than the night before, when the choir echoed the same micropolyphonic lines across the aula of the Kiasma art museum. There the cool distance of the work really spoke in a mesmerising way, with an unreachable caress.