The phrase "big boom" refers to a loud noise caused by an explosion or a sudden happening that makes a strong impact or creates a significant change. Full definition
That translates into a loud stream of audio with big booming bass, which the speaker certainly does deliver. (androidcentral.com)
Pretty simple for me, I could easily believe in gods existance with just a few miracles performed, big booming voice from the sky, ect.. (religion.blogs.cnn.com)
Without it, we would have seen bigger booms and busts and more variable and, probably, higher inflation. (rba.gov.au)