To start with it sounds like out-of-tune pianos. Ives dipped his toes into quarter-tonal waters but Wyschnegradsky went for total immersion as a fully-fledged microtonalist in most of his large output. Ivan Wyschnegradsky (1893-1979; also Vïshnegradsky), was a Russian composer rooted in science, philosophy, oriental thought and the music of Scriabin. He first composed in microtones in 1918 and a quarter-tone piano with three keyboards was built to his design in 1924. After that he published a treatise on quarter-tone harmony and was connected with the Parisian avant-garde around the Second World War when Boulez took part in a performance of his Cosmos.

The trouble is that you could take the quarter-tones out of most of his two-piano Preludes and come up with something straightforward and familiar. There is plenty of range in the selections from Wyschnegradsky’s Preludes where the quarter-tones affect both harmony and melody. It’s a weird sound that has its fascinations, but his Etude (1956) for a normal piano is in a luscious post-impressionist idiom.

Ives completed his Quarter-Tone Pieces at the end of his composing career – he thought of them as studies and borrowed extensively from his own music in the new context. These performances are slower than the first recording by George C Pappastavrou (editor of the score) and Stuart Warren Lanning (a 1967 Odyssey LP) but the way Ives moves in and out of his quarter-tones is always fascinating – this is a classic in the genre. I can’t tell from the uninformative CD booklet which pianist is playing Ives’s Three-Page Sonata. The edition used is the one made by Henry Cowell published in 1949 and not the more elaborate later one by Kirkpatrick. It sounds like Schleiermacher, whose presence is a guarantee that everything will be fastidiously delivered.