I'm writing a paper on the song 'Mood Indigo' by Duke Ellington, from 1930. It is known for its achingly beautiful sound, which is achieved via three-part harmony of trumpet, trombone, and clarinet. However, it places the trombone in its highest register, and the clarinet in its lowest register, so that the order of voicing from top to bottom is trumpet-trombone-clarinet. This combined with mutes in the trumpet and trombone has the effect of creating a unique, elusive tone color.
I read from John Hasse's "Beyond Category" biography of Duke Ellington about the arrangement for Mood Indigo: "As Gunther Schuller has asserted, the resulting tonal colors probably had never been heard before in all of music history."
I imagine he's right if you restrict your search to harmonies involving muted trumpet, muted trombone, and clarinet in the same voicing order. But are there any examples of simply voicing clarinet below trombone at all, in any previous works? I would be interested to know of them.