Readers of a nervous disposition regarding Allan Pettersson’s music should start this disc with the Four Improvisations (1936). The opening’s rusticity will come as a surprise; the remainder oscillates between Bartok in folk-mode and Hindemith. Like the other shorter items, the Improvisations are stylistically anonymous, unrecognizable when set against the monumental, Angst-driven output of the composer’s maturity, and strangely patchy in quality. When vast symphonic canvases could later be erected from the sparest of material, the two-and-a-half-minute Fantasy (1936) seems prodigal by comparison in achieving so little with so much. On a similar scale, Lamento (1945) – Pettersson’s only surviving piano work – is quite forgettable. At over 14 minutes in duration, the 1948 wind Fuga is certainly no trifle; its obsessive reliance on pure counterpoint (with precious few textural contrasts) is suggestive of the later symphonist. Yet it just does not sound like Pettersson, making the vibrancy of personality evident in every bar of the Concerto of a year later all the more extraordinary. This really is a masterpiece, albeit a discomfiting one, written by a composer who was also a master string player. Karl-Ove Mannberg and the Fresk Quartet recorded it for the Swedish label Caprice, a fine performance fiercely recorded, emphasizing the dissonance of expression. Hoelscher and the Mandelring are equally good and CPO’s sound has less glare, softening edges that were unnaturally severe with no loss of impact. A revelatory issue.'