I did not know this American music as a youth. It came to me via a young German named Sebastian who made a cassette tape of the whole session for us when we lived overseas in the early 90's. But I miss the warm crackles and pops captured on the cassette* as he recorded it from his parents' vinyl LPs.
I love the crystal clarity of Ella's voice contrasted with Louis' gravelly murk. Together, they made musical chiaroscuro.
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*I found the tape in a recent move and have been listening to it in my car -- the only cassette player left.