Music can definitely affect my writing, and not simply because it's playing and providing a backdrop while I'm writing. If I've been listening to a song, piece, or type of music, that strongly resonates with me, I find that when I sit down to write, some of its motifs, rhythms, and cadences show up in what I write and the way I write it. If you pay attention to how music affects you, you will find it is an extremely powerful energy. Some music can soothe you, some irritate you, some gladden you, and some spur you on to action. Music definitely does affect a writer, even if he's unaware of its effect.