Crumb’s innovative classics of the extended piano are now attracting more pianists – there have been at least six recordings of Makrokosmos 1, starting with that by the dedicatee, David Burge, on a Nonesuch LP (5/75 – nla). It’s not just the piano which is extended with amplification but also the pianist, who is required to play on the strings inside the instrument and trace elusive harmonics. At times various objects are placed on the strings to change their sound, in the manner of Cage’s prepared piano. The player also has to speak, sing, groan, whistle and tap on the soundboard – a demanding range of activities where the difference between performances is usually indicated by the pianist’s voice and his/her whistling ability.

Crumb called his 1972 cycle ‘Twelve fantasy pieces after the Zodiac’, with Book 2 as a second set. He said: ‘Each piece is associated with a different sign of the Zodiac and with the initials of a person born under that sign.’ A kind of Enigma Variations, in fact. The seductively evocative sounds are generally well recorded in all versions. Robert Nasveld, in his two-CD set, has some awe-inspiring groans and shouts louder than Burge. He has the best whistling but his Chopin quote in ‘Dream Images’ is too loud to ‘emerge from silence’. Jo Boatright is the best here – and the effect is magical. Christiane Mathé is rather faster.

In choosing between these versatile players, price is a factor. Nasveld’s two-CD set of the complete works is well worth having; of the single CDs Toros Can has the most immediate recorded sound with stronger amplification; but Boatright is the bargain at mid-price with a thorough CD booklet, too