Personally I have http://RainyMood.com http://RainyMood.com and http://SimplyNoise.com http://SimplyNoise.com (on brown noise, medium oscillation) running 24/7;

Personally I have http://RainyMood.com http://RainyMood.com and http://SimplyNoise.com http://SimplyNoise.com (on brown noise, medium oscillation) running 24/7; it helps me concentrate as well as sleep.