Sound of a Black Hole

Regarding my Infrasound post below, Marc Laidlaw points us to this article about the discovery of sound waves from a supermassive black hole more than 250 million light years from Earth. According to a NASA article, "the 'note' is the deepest ever detected from any object in our Universe." Marc asks "Could it be that the supermassive black hole at the galactic core is responsible for the sense of cosmic dread that permeates our galaxy?" Link