I'm listening to a suberb audiobook at the moment, "The Sisters Brothers" by Patrick deWitt. It has the wry wit of a Coen Brothers western, and keeps impressing me with how well done it is up close.
The narrator, William Hope is brilliant. The two brothers have very different characters and their story is told by just one of them. Hope's voice is fine-tuned to that brother but instantly modulates to the other when reporting his speech, or any other character as well. It's effortless, it's the same voice, and yet it is an entire cast of characters - quite wonderfully done.