Peter K. Frey and Daniel Studer have been working together as a duo for 20 years; Zeit celebrates this milestone by folding two separate gigs, recorded in 2004 and 2018, around each other, editing across time to generate one seamless construction. The material from 2004 added Jürg Frey and Alfred Zimmerlin to the basic duo for a concert recorded at the Rote Fabrik in Zurich: each musician placed in a different room played sounds from a master-score that were diffused into a fifth space, leaving audience members to decide whether to focus on the soloists or the randomly emerging quartet music. The duo pieces, recorded last year, are fully improvised, with (Peter) Frey and Studer morphing between sprays of notes, dot-to-dot textures and distorting mirrors of electronic sound. Placing these two sorts of music together creates a counterpoint of notably varied energies – improvisational intention set against coincidental overlaps of sound. A thoughtful and worthwhile disc.