Many well-known musicians of all genres offer royalty-free samples
via CD for composers, musicians and so forth. Generally these are
extremely expensive - averaging $75 to nearly $200 per disc.
SourceCodeX (not so well-known) now offers ~~~Alien Ambience~~~
at "starving musician" budget price for your use. You get 100 high-
grade wav files of 610 MB total running 18 to 60+ seconds each and a
6-minute bonus track is included.
More info & demo clips here: http://sourcecodex.eer-music.com
Current sales listings:
Example of item for sale:
Thanks for all the deep drones inspiration . . . you know who you are.