Here is a couple of examples of how you can generate beautiful background sounds directly in linux command line with the play command (install the vox package in your linux distribution).

Sound in space (sure, lets image that would work)

play -n -c1 synth whitenoise lowpass -1 120 lowpass -1 120 lowpass -1 120 gain +14

Here is a 30 second sample of the output from the above command (I used Audacity and Pulseaudio to record the output from the play command):

Waves hitting the shore (if your are a more down to earth person)

play -n synth brownnoise synth pinknoise mix synth 0 0 0 15 40 80 trapezium amod 0.2 10

Again, here is a 30 second sample: