Electronic music producer Moby’s Ambient 23 collection contains some compelling pieces that are evocative and reward close listening. The tracks alternate between synthesizer-based electronic washes of sound and austere piano pieces built upon a few still tones. One of my favorites of the former type is “amb 23-11.” Structurally the music is a I-vi-V progression, but in slow motion. Each chord lasts about twenty seconds, and once around the cycle about one minute, which means the cycle is heard ten times over the ten-minute piece. The repetition foregrounds basic music theory: how two of the chords (I and V) are major and stable-feeling, while the linking chord is minor (sharing two pitches with the I chord) and unstable-feeling. Timbrally “amb 23-11” slowly rises and falls in brightness as white noise textures grow out of the sides of the stereo field. But overall, the music remains muted and calm–as interesting as it is ignorable, to remix the famous Brian Eno quote about ambient–and evokes dark clouds floating on a horizon.