It definitely sounds like machinery- similar to sounds I've heard in factories, but much more prolonged and obnoxious. I certainly wouldn't call it majestic or trumpet-like; more like metal grinding on metal.
It's obviously the motherships moving into position. Really though, this is a wild phenomenon.
I have a hard time believing this one (no hyperbole). Unlike crop circles, there is no compelling evidence they aren't all faked. The only way one could verify this is a real phenomenon is to experience it first person.
All that being said, I don't automatically disbelieve something I can't objectively prove. I have been passively interested in this for a few years but that's about it.
I heard it was underground bases.
I think I spend too much time listening to weird music. To me, that just sounds like something Sun Ra woulda cooked up.
Bashar spoke of this phenomenon relatively recently, mentioning that it was an opportunity to discover more of the self.
In other words, it's a catalyst (for some) to delve into mystery (the infinite), and seek.