When I write a character, I picture not just the character but the voice, same with reading, and going from a paper or eBook to an audio book usually breaks both. Books I write rarely include characters from Manchester (UK), so reading voices with my strong accent would definitely break a lot of my books. It is also the reason I sometimes don't enjoy movies if I have read the book. It is not a one way street though, some really good narrators can improve the experience a lot, same with good directors.