Anything making sound, CD, radio, TV, DVD that has irregular intervals in it. If it is too repetitious sounding it doesn't work. Does have to be something I like for best results, soap operas would never work nor would techno, but otherwise a very wide range of titles. Not close enough to the refrigerator to hear it but it does have quite a range of interesting sounds. If the birds are singing loud enough that works good. I spend more time thinking about what I am writing or gluing together so whatever is running can be on auto repeat for hours. I do seem to like west coast rock better than east coast. The older the jazz, the better. Classical music with a unique sound or arrangement. If a western is on the TV, except for a few select ones, I don't hear it at all unless it is a spaghetti western. One particular movie works quite well, Johnny Depps Lone Ranger, dialog and music. Where as the pirate series is pretty much just background noise. For music, I like lots of rock from the 60s and 70s, lots of UK from the 80s, not much after that. Nirvana is great for artwork, the change ups keep it interesting.