“The maple tree’s not made of wood / It is wood.” Kenneth Koch’s lines seem to fit, paradoxically, the double bass of Norwegian virtuoso Sigurd Hole. Soughing and snapping, creaking and groaning, humming and thrumming, it seems—on his new record Lys / Mørke (Light / Darkness), whose release this event celebrates—to have reverted to the forest from which it was hewn.—E.E.