Carl Philipp Emanuel Bach: Late keyboard pieces (ECM New Series)**** (4 of 5)No label generates such a buzz around new releases as the quirky Munich-based ECM which, after 48 years of high output, still manages to produce the unexpected, and at high quality. To find the senescent music of C P E Bach in a series that specialises in living composers is surprise enough. To hear him played on an esoteric Tangent piano is altogether a delight.The shortlived Tangent piano, mostly built by August Späth in the mid-to-late 18th century, allows an artist to express a personal sound - according to the Russian pianist, Alexei Lyubimov. Certainly, the sound on this recording is unlike any other keyboard timbre I have experienced. At one extreme it has something of the boxiness of John Cage’s prepared piano. At the other it reveals angelic beauty in music of no great genius.CPE Bach never listened when his old man told him to leave the public wanting more. He comes up with an intriguing Rondo or Fantasie and, instead of cutting short at two or three minutes, proceeds to work the theme for all it’s worth and more. Despite the composer’s best efforts to beat his tunes to death, Lyubimov makes a strong case for the late sonatas.Remarkably, the Tangent helps redeem this music from mediocrity, adding pastel colours to the sound picture, along with a hint of unpredictability that could almost be Cageian, or aleatory. No keyboard lover should dare to miss this recording.___Norman Lebrecht has written 12 books about music, the most recent being Why Mahler? He hosts the blog Slipped Disc, writes a monthly essay for Standpoint magazine and is writing two more books.