Low Frequencies, Dark, Simple, Sinister, Gloomy
This collection requires little explanation. These are very simple sounds that are mainly on the lower end of the frequency spectrum. In fact, most of them are so simple, you may use them in conjunction with other sounds that lack bass. Or you might want to use them in an area where there are lots of other sound effects, or conversely, where you don't want much sound at all, but need a very minimal atmosphere.