I have experimented a little with NASA's Sun sound recordings. They are archived over at the Stanford University website now. I originally wasn't using them for research related to dreams but I noticed a large increase in dreams the same night if I listened to a specific one for about 10 minutes before going to sleep; (as a note, this was done on a larger stereo system with a sub woofer, and I haven't tried my expensive studio headphones yet).

Among the other notable effects is after 10 minutes, most of the time I would have the "whole body vibrating" effect that a lot of people claim they experience when they enter SP (Sleep Paralysis).

Here are the links to the Stanford site:

The sun sound I use is here - http://soi.stanford.edu/results/all_modes_l_0_1_2.aiff

This is the general page of the Stanford Sun Sounds - http://solar-center.stanford.edu/singing/singing.html