SCOTT SIMON, HOST:

"How To Train Your Dragon 2" opens this weekend around the country. The Academy Award winning sound designer Randy Thom, who's worked for NPR, did the sound design for this animated film and we asked him to deconstruct one particular scene where the hero, Hiccup, confronts a menacing group of dragons in the cave.

(SOUNDBITE OF FILM, "HOW TO TRAIN YOUR DRAGON 2")

RANDY THOM: That growling and snarling is a combination of a leopard and me. When I growl, I go into some dark studio where nobody can see me making a fool of myself. And I make sounds like...

(SOUNDBITE OF FILM, "HOW TO TRAIN YOUR DRAGON 2")

THOM: What happens then in the scene is that Hiccup mesmerizes the dragon, first with his fire saber, and then with this kind of cloud of gas that he ignites. The way that we recorded the fire part of the fire saber was just to get a rag and put it on the end of a long pole, put gasoline onto the rag and light it and wave it around in the air, which gives you that kind of dynamic, moving fluttery sound as the flame moves through the air.

(SOUNDBITE OF FILM, "HOW TO TRAIN YOUR DRAGON 2)

THOM: For the smoke part of the fire sword, all we did was record a fire extinguisher.

(SOUNDBITE OF FIRE EXTINGUISHER)

THOM: In general, in the scene, we hear a variety of dragons off screen and some of them are camel sounds, some are dogs, some are me, some are birds of prey that I have pitched down by one or two or sometimes even three octaves to make them much lower. And I think it works, in part, because, you know, we know from studying evolution that birds are almost certainly descended from dinosaurs. And so it's kind of believable that a pitched down, enhanced version of a bird would sound like a really big reptile.

(SOUNDBITE OF FILM, "HOW TO TRAIN YOUR DRAGON 2")

THOM: The sounds are very evocative. They bring up all kinds of visual images. And it doesn't occur to filmmakers very often that specific concrete sounds in the real world that they might listen to in preproduction, before they start shooting the movie or animating the movie, could inspire the way the film looks. And I started making sounds very early on "How To Train Your Dragon." And those sounds did in fact, to some degree, inspire the look of the movie.

(SOUNDBITE OF FILM, "HOW TO TRAIN YOUR DRAGON 2")

SIMON: Sound designer Randy Thom on the movie "How To Train Your Dragon 2," opening this weekend. This is NPR News. Transcript provided by NPR, Copyright NPR.