Fred Frith’s most recent collective ensemble, Cosa Brava (Fred Frith, Karla Kihlstedt, Zeena Parlins, Matthias Bossi, Shahzad Ismaily and The Norman Conquest) is best known for its tricksy compositional work, but here feature in an imaginary performance painstakingly compiled only from the improvised passages of numerous live recordings (in a process similar to Neil Young’s luminous arc, but to very different effect).