Sorry...NOTHING beats the F-4 Phantom II for that. Two J-79s at full afterburner on a low 450-knot airshow pass is just one of the most amazing walls of sound you'll ever hear. Raw, brute, unadulterated power, and a total triumph of sheer thrust over aerodynamics. :)
Old "Double Ugly" is the third-loudest airplane I've ever heard. #2 was a B-1B in full afterburner, and #1, by a mile, was the Concorde.
}:-)4
The Phantom II is proof that if you strap big enough engines on a brick, it will fly.
The Harrier remains the single loudest SINGLE engine aircraft that I have ever heard.
Loud enough to make you puke.
Then you need to look at the B-58 - four J-79s. Worst noise though was from the Jaguar - not for loudness, but they have the worst whistle I've ever heard at idle. Dogs for miles will roll in pain.