Deep space
Chandra has detected sound waves coming from a supermassive black hole....
In musical terms, the pitch of the sound generated by the black hole translates into the note of B flat. But, a human would have no chance of hearing this cosmic performance because the note is 57 octaves lower than middle-C. For comparison, a typical piano contains only about seven octaves. At a frequency over a million billion times deeper than the limits of human hearing, this is the deepest note ever detected from an object in the Universe.
From NASA
Apparently this discovery might help to explain a disparity between hot and cool gas in galaxy cluster.