Iceland is exporting lots of contemporary classical music lately, and the world is listening. The principal appeal would often seem to be, as it were, topographic; critics are forever citing a sense of expanse and emptiness that evokes the Nordic landscape. The composer Anna Þorvaldsdóttir, who was born in 1977, is one of her generation’s best and brightest, having received commissions from top symphonic and chamber-music ensembles in Berlin, New York, Paris, Munich, and other hot spots. She describes her new METAXIS for the Iceland Symphony Orchestra as “an installation for scattered orchestra and space.” It premieres at Harpa, Reykhavík’s glass-enclosed concert hall that opened in 2011, towering over the harbor like an iceberg or giant hunk of mountain crystal, with soaring lobbies that raise the spirit and perhaps intimidate at the same time. We’re visualizing listeners navigating as they wish among clusters of instrumentalists positioned per the composer’s specific instructions. Given the aleatory and subjective elements, some listeners will surely want to stay all night, but that’s not an option. Free tickets are good for admission either at four P.M. or five P.M., and the performance lasts just half an hour. Somehow, Eva Ollikainen will conduct, somehow assisted by Ross Jamie Collins. —Matthew Gurewitsch