Album review: Brahms/Schumann, Strings Attached - Arno Piters/Royal Concertgebouw (Challenge) Composer Geert van Keulen reshapes Brahms's Clarinet Sonatas in F minor and E flat major after the model of his Clarinet Quintet in this alluring disc of arrangements. The soundworld is notably darker than Brahms's original, but the result is fluid and idiomatic. Principal clarinettist Arno Piters is handsomely supported by his colleagues from the Concertgebouw in this and in Schumann's Fantasiestücke - as fiendish a test for the strings as it is for pianists.