The latest project from Hans-Joachim Roedelius of Cluster/Kluster and Harmonia fame is Qluster, a duo with Onnen Bock of Zeitkratzer. And even though Bock is roughly half Roedelius' age, the two men communicate very well on the seven analog synth improvisations that make up the disc. Many of them fit into the darkened kosmische music territory Roedelius explored so ably in the 1970s, before moving into neo-classical composition, but others represent entirely new areas of investigation for him. "Wurzelwelt" sounds like an early-'80s instrumental by the Residents, with its dripping-water percussion sounds, haunted-house music-box sounds, and off-kilter melody. "Haste Töne," on the other hand, is a slowly blossoming piece not far from early-'90s ambient work by Aphex Twin or the Orb. And Roedelius and Bock are masters of the recording studio; there are sub-bass rumbles here that would make Bill Laswell swallow his tongue with envy. Like many classic analog synth discs from the '70s by Roedelius, Klaus Schulze, Tangerine Dream, et al., Fragen sounds like an entirely different album when heard through headphones rather than speakers, and vice versa. But no matter how you listen to it, it's a very strong addition to the Roedelius discography, and the history of synthesizer music in general.