I've kept an open mind reading and listening to the various loud noise accounts. I doubt we will know exactly what this noise represents, but I've come across a few possible explanations:
1. As Planet X/Comet Elenin/Nibiru (I believe they are all one in the same) arrives within our solar system, a vacuum is created during certain
alignments. This is not heard in space, since space doesn't have sound per say. This is energetic waves that when faced with our atmosphere or
oxygen, it converts into sound.
2. HAARP (sorry, I know everyone is sick of hearing this). I've reviewed the videos of former HAARP scientists and also the Russian diplomat (not
sure of his position at this moment) who threatened to use HAARP against the USA (this was only a few weeks ago). When HAARP is turned on, the energy
goes up in our atmosphere and back down like a roller coaster, but over large spans of land. If HAARP was turned on in the Pacific Northwest
(Oregon/Washington), the energy waves could hit in the east coast. If Russia claims to want to use HAARP as a weapon against us, then they have the
ability to use/shoot long range.
3. NASA's Cloud Machine. Since many of the reports are on the east coast, the Cloud Machine sounded very similar to what we heard on the audio tapes.
The only problem I have with this is what about the west coast audio? No explanation for that unless NASA has Cloud Machines all over. Probably
unlikely in a place like San Diego, CA as there isn't 125,000 vacant acres of land near the coast.