Try this site, I use it occasionally to help me ignore the fan &#x2F; 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.<p><a href="http:&#x2F;&#x2F;mynoise.net&#x2F;NoiseMachines&#x2F;throatSingingDroneGenerator.php" rel="nofollow">http:&#x2F;&#x2F;mynoise.net&#x2F;NoiseMachines&#x2F;throatSingingDroneGenerator...</a><p>I use that one, Darkness, overall volume up a little and first two sliders down a little.  Works like a charm.