A leading figure of the Swedish avant-garde, Rolf Enström is primarily known for his intensely complicated and darkly hued electronic works, of which the five brooding pieces on Quarks, his 2007 release on Caprice, are representative examples. Because Enström's dense textures, skittering gestures, deeply resonant backgrounds, and sharp timbres change little from piece to piece, and seem to share a common electronic vocabulary, Spin (1995), Charm (1996), Strange (1997), Up! (1999), and Down: (2001) flow together rather evenly and connectedly, almost as if they were movements of one long tone poem about subatomic particles. Enström's mysterious colors and spacious effects are particularly well suited to the hybrid SACD format, which permits vast sonic dimensions and a wide range of dynamics, and captures the softest and remotest pulses as well as the loudest and closest blasts. This is a fine album for adventurous listeners who want to hear electronic music of consistent high quality and intellectual depth that is free of clichés, though others may find that these soundscapes are too edgy in style, abrasive in feeling, and alien in expression for comfortable listening.