[osxrand]

Try this site, I use it occasionally to help me ignore the fan / vibration noise in this building and it works really well (for my purposes at least). There are plenty of different presets to choose from or tune your own.

http://mynoise.net/NoiseMachines/throatSingingDroneGenerator...

I use that one, Darkness, overall volume up a little and first two sliders down a little. Works like a charm.