When I sit down to work on a novel, I try to engage my other senses in ways that open up my thinking but aren't intrusive. So, I usually have a candle or scent diffuser going, and I almost always music playing. The music needs to be wordless or in a language I don't understand, and the dynamic these days is dark and moody. As a teenager in a punk/artsy college culture, I could never imagine a future where I would not just tolerate but prefer long-form, new age-type compositions, but here I am, requiring those expansive, airy tracks to loosen me up like wine. I blame Peter Gabriel's Passion soundtrack to The Last Temptation of Christ for chasing the punk out of me.
Current favorites for writing include Explosions in the Sky and Ludovico Einaudi. I have yet to find the right internet radio station--most of the ambient oriented ones tilt towards "relaxation," and that isn't quite the service I need. Dark Ambient over-corrects, and Drone Zone would be perfect if there were drums once in a while. Otherwise it puts me right out. I'm listening to it right now, and I'm beginning to turn into a statue.
But it's not the music, really. It's about capturing and sustaining the physical element that we think is inspiration, that surge we mistake as the catalyst for creation, when it is more likely a byproduct of the process. I suspect the illusion has something to do with hormonal nostalgia. Everyone's young when they listen to music, even if the music they are listening to is for old folks like me.