This is white noise generated from the open source Android app Chroma Doze, https://github.com/pmarks-net/chromadoze, with the pitch set more towards the lower end of the spectrum.
This is a normalized and trimmed version of http://freesound.org/people/RSilveira_88/sounds/216306/
I made the modifications to make it more suitable for an SMS text notification. License is CC-BY to RSilveira_88 …
April 1st, 2015