I just discovered this little website that mixes different ambient background sounds that are themed after different story franchises, and lots of other concepts as well. Want to feel like you're cozied up on that ancient, worn sofa in the Gryffindor common room, in front of the crackling fire, Hermione studying at your side, Ron giving endless sidelong glances because he's such a dunce? They've got you covered! I'm not usually one for gimmicks, but I really, really like this idea. You can modify them on the fly, btw. Like, the one I'm listening to now has a bird that was constantly chirping. Too much. You can look for the loop that has that particular sound and click the Random button and set it to only play that loop every so often. It gives you different lengths of time to choose from. You can adjust the volume for each given loop; you can fade them left or right to give directionality. Best of all, looks like you can create your own combinations and save them! You don't need to download anything if you're on a computer, just click and enjoy. There is a downloadable mobile app version for those of you who prefer mobile platforms for your writing http://www.ambient-mixer.com/ Here are just a few of their top pics.