Well, the sweetest sound I ever heard was a cry from my first born, but since we seem to be speaking aviation here, and loud aviation at that, There are three seperate times where the sound was totally burned into my senses.
First time, I was serving on a Destroyer, USS Eversole, and we were about 10 miles west of Catalina Island, and several miles south. It was lunch time, and most of the crew was in line on the port side, waiting to get into the chow hall.
Suddenly, it was as if the world exploded, and we were in the middle of the fireball. The ship literally shoke from the shock.
I could hear the planes on the starboard side as the flew past us. A pair of F4's, supersonic at about 50 feet above the water, had passed over us.
I ran through the O-1 level and exited the starboard hatch, just in time to see them about 10 miles out. They were in a high G turn, and slowing down. As they passed over us again, much slower, they waggeled their wings as if to say, "Gotcha".
Back in the 80's, I lived close enough to Oshkosh that I attended every EAA flyin. One year they had a Marine Harrier there. I stood about 100 feet away as he lifted vertically and hovered about 100 feet above the runway. They warned us to open our mouths and cover our ears. It still hurt.
A couple of years later, same venue, they had the Concord visiting. Again, I was in the crowd, about 100 feet from the edge of the runway when they started the tackoff roll. Since the field is not to far from Lake Michigan, I don't believe they held anything back. Very impressive, and noisy.
Ok, one more, duiring the celebration of the 50th aniversary of the Battle od Britain, there was a Mousquito there that year. A pair of Rolls Royce Merlins at full throttle a few hundred feet above the centerline of the runway,,,, Sweet music, Sweeeeeet.
John Miller