Exclusive: Ben Burtt's WALL-E Sound Masterclass
The world's most renowned Sound Designer teaches RT
Other sounds, like EVE's laser for instance, are made by finding unusual sounds that most people wouldn't hear in the course of their day. The sound of the laser is made by striking a very long Slinky. You stretch it out, and there's a special way that you can impact it to get that sound travelling along the Slinky.
It's similar to the blaster sound in Star Wars, but that was a very long cable attached to a radio tower. The same principal applies when you hit it - the sound travels along the wire and the high frequencies travel faster than the low frequencies so when you pick the sound up at the other end of it you get high, then middle, then low. You get a pass-by feeling to it.
I couldn't use the Star Wars blaster, because I wanted to come up with something new, but I tend to think in the same terms - what does a laser sound like? I've already established it in Star Wars, so it makes sense to come up with a distant cousin for WALL-E.
There is a language of sound, and once you've established something it's hard to approach it in a different way. The droids that came before us helped a lot in this movie!
I keep track of the number of sound files that we've made for the film, but it'd be hard to guess how many there are playing during any particular moment. We made something like 2,600 sound files, which is more than I've made for any single feature film that I've ever worked on, mainly because there was dialogue as well as sound to support. There was also a tremendous amount of development over the years and a lot of the dialogue changed, so that number includes sounds we didn't end up using.
And the animation is so densely packed with action - there are so many things happening at any time and usually there's a sound associated with everything. It's easy to design one interesting sound but when you've got ten things happening at one time and they're all there for fractions of a second, it gets difficult to orchestrate them and figure out the clarity. The mixture works very hard in the film to make something that's coherent. It's easy to make 2,600 sounds, but the next thing is to play them back in a way that makes some comprehension to the ear in the brain.
Ben's contribution wraps up WALL-E Week on RT and sister site IGN. For a round-up of the special WALL-E features we've run this week: