Given the name Con-Pilot may I suggest Concorde might have been a tad noisy.
Well must say that the time between hearing a B-58 takeoff and the Concorde takeoff was rather long, I'd still have to give the edge to the B-58.
And the question was, "Loudest
military aircraft."
Watching a night time takeoff of a B-58 was truly awesome. Especially on a wet runway. Noise, fire and smoke (steam).
But the loudest aircraft (okay, okay heavier than air vehicle), by far, with no competition, was the Saturn V rocket used in the Apollo Space program.