The Necks—an Australian trio consisting of keyboardist Chris Abrahams, bassist Lloyd Swanton, and drummer Tony Buck—have been releasing recordings of their finely shaped improvisations since the late '80s. There are elements of jazz, ambient, rock, and other styles here, but their music can’t be reduced to a single genre. Like a number of The Necks' albums, Open consists of a single lengthy track. Droney monochord fingerings and shimmering chimes mark the start of the piece. Melodies that evoke Chinese, Indian, and Native American music come into play. Psychedelia and the great British improv unit AAM spring to mind, and so does the free-meter alap section of a traditional raga. Open also evokes the spiritual jazz of Alice Coltrane, Pharoah Sanders, and others. Despite a sense of overall stasis, the sounds keep changing and engaging. A few delicious bass tones might make you think the band is ready to blast off, but they don’t; instead they provide more subtle pleasures. Buck can supercharge the moment with a thwack or two. And Abrahams—whether spinning out minimalist passages on piano or sustaining a just-right chord on organ—is excellent.