On the first page of the first dream song we read, stanza 3:

What he has now to say is a long  wonder the world can bear & be.  Once in a sycamore I was glad  all at the top, and I sang.  Hard on the land wears the strong sea  and empty grows every bed.

Three voices, two lines each, speaking in one stanza. The first voice is objective, the poet introducing his character, giving the gist of his theme. The second voice may be received as Henry's voice, recalling the good times, sycamores and songs. But the third voice is different from either; it is generic, representative, apocalyptic, Mankind rather than any particular man, Henry or J. B. or anyone else. In this third voice the feeling is universal rather than local; it is consistent with the first and second voices, but distinct, as if its experience were the history of the world rather than the fate of a man. It is my understanding that these three voices are nearly as many as the poet requires for his long poem: the unidentified friend who addresses Henry occasionally as Mr. Bones uses an AI Jolson voice and a chocolate idiom to admonish his white American friend, but beyond that degree he is hardly distinguished from any other figure, silent, sympathetic, watchful. So the three voices are nearly enough.