The title track on Drone Positions by the Gothenburg, Sweden, group Trio Ramberget is a promising taste of the full set, which is due out on September 29. The ensemble consists of three horn players: Gustav Davidsson, trombone; Johanna Ekholm, double bass; and Pelle Westlin, bass clarinet. They are joined on the album by a half dozen guests playing, among other things, piano, guitar, vibraphone, and a tape deck, as well as singing. “Drone Positions” is a luxurious descent into deep deep timbre. The sounds are dense and glottal, rich and vibrant. There is an earthy sibilance throughout, and a steady — if glacial — sense of melodic development. It’s wondrous.