‘My inspiration comes always from the voice. I have more records of old voices than I do of old pianists.’ That mantra, from an interview Horowitz gave to Thomas Willis in 1974 (one of two included on this release), coloured everything he did and gave his interpretations a flexibility that meant every recital was a new experience, which is why this one, given when he was 83, is such a fascinating document. It took place in Chicago – where he’d had his first major American success nearly 59 years earlier – and was broadcast locally via the city’s main classical radio station WFMT as a thank you to the city itself, which had always warmly welcomed him.

No one could imitate anything Horowitz did, and that’s particularly true of his Scarlatti, which combines lightness of action and the subtlest of pedalling: the sharp angles of Kk380 are preserved without a hint of aggression, while Kk135 is filled with a quiet playfulness, the brilliance almost understated.

Schumann’s Arabeske, new to his DG output though by no means new to his discography as a whole, has a pearlescent beauty, a reactivity that gives new tints to the main theme each time it reappears. In Liszt’s Petrarch Sonnet No 104, too, there’s an assurance to the way it unfolds that’s utterly compelling, its dying moments truly moving, even if it does get a tad tangled in some of the more physically demanding passages. And the Sixth Soirée de Vienne is full of rapturous beauties (just sample the murmured filigree beginning at 3'59"). Horowitz’s Chopin is not to all tastes, being too romantic for some, but it’s hard to resist his Op 7 No 3 Mazurka, which is lent a febrile instability. The First Scherzo, though, is a bit of a car crash that even moments of wondrous singing tone can’t rescue. The audience applause is as warm as ever – perhaps out of relief as much as anything else. Ah yes, the audience: late October in the Windy City is perhaps inevitably going to mean a lot of snuffles, sneezes and coughs, and they form an unwelcome counterpoint to the proceedings on stage.

Mozart, Horowitz reveals in a radio interview with Norman Pellegrini recorded the day before his Chicago recital, had been a great love all his life but it was only latterly that he’d felt ready to share it on the concert platform. If others find a more dolorous quality to the B minor Adagio, Horowitz is in his element in the D major Rondo, which glistens and glints with ever-changing hues. And he turns the first movement of the C major Sonata, K330, into a veritable opera in miniature. The Scriabin C sharp minor Etude, Op 2 No 1, is beautifully sung, while the Moszkowski ‘Etincelles’ – long a favourite encore – has enormous spirit, if not quite the carefree freedom of earlier incarnations, not least the 1975 Carnegie Hall recital (RCA). With good sound and a fascinating booklet essay, this is another compelling addition to the vast Horowitz legacy.