posted on Jul, 12 2011 @ 10:30 AM
The first thought that came to mind was a combine/harvester or some large farm equipment.
Sounds can be so tricky, weather conditions can certainly carry loud sounds unusually long distances but those tend to be directional, you can tell
which way they come from, and unless you have some expensive audio recording equipment it just won't sound on video like you heard it live.
Ah for a hot-air balloon in times such as this. Then you can just pop up for a look around and pinpoint the source of the sound and the mystery would