Star Wars sound designer Ben Burtt explains the difficulty of making convincing explosion sounds in the movies: "Real explosions are really difficult to record, because they're so loud, and quite often they're so sudden. ... A normal recording system doesn't get something that's very interesting." To get a movie-worthy explosion, Burtt traveled to military bases and accidentally blew up some microphones in the process. Here's a two-minute explanation of how he got the sounds that led to the end of the Death Star:

And tying it all together, Burtt explains how he popularized the title "Sound Designer" to explain the many sound-related roles he played. Amazing stuff:

See also: Creating the Lightsaber Sound and Creating Voices for Chewbacca and R2-D2.