I love the late reading style - the voice weak but well suited to the run-on digressive, seemingly narrative (but not), lazy-toned yet ethically sharp poetics. Listen to the 23-minute reading he gave at the 92nd Street Y in 1967. Dazzling - moving and beautiful. He reads "Of Being Numerous."
Perhaps the most moving of Oppen's statements or readings is his introduction to Charles Reznikoff, before a reading by "Rezzi" in 1974:
[Reznikoff] had bought a letterpress, and everyday, every evening after work, Reznikoff set two lines of verse, teaching himself to set verse, as he worked at it. And this way he printed all of his first books by himself. We, Mary and I that is, have carried these poems in our minds through everything that has happened to us since we were nineteen or twenty years old. I don't know of any poems more pure, or more purely spoken, or more revelatory. I professed before, I think the young of my generation were luckier than the youngest in this audience, in that we had to go searching for our own tradition and our own poets. What we found was Reznikoff, and he's played — I cannot say how important he has been to us, as I think he will be to you, and this is what I wanted to say to Charles Reznikoff when he said to me, 'George, I think we all do the best we can.'
(The whole text of the introduction is here.)