Sound designers for film and games often use creative methods to generate the appropriate sound from existing sources, rather than through signal processing techniques designed to synthesise or process audio. One well-known technique for generating the Doppler effect is to swing a microphone back and forth in front of a sound source. This was used in the original Star Wars to generate the original lightsaber sound. As described by Ben Burtt, the sound designer;
“… once we had established this tone of the lightsaber of course you had to get the sense of the lightsaber moving because characters would carry it around, they would whip it through the air , they would thrust and slash at each other in fights, and to achieve this addtional sense of movement I played the sound over a speaker in a room.
Just the humming sound, the humming and the buzzing combined as an endless sound, and then I took another microphone and waved it in the air next to that speaker so that it would come close to the speaker and go away and you could whip it by. And what happens when you do that by recording with a moving microphone is you get a Doppler’s shift, you get a pitch shift in the sound and therefore you can produce a very authentic facsimile of a moving sound. And therefore give the lightsaber a sense of movement…”
Ben Burtt, by the way, is one of the most successful sound designers of all time. One of his trademarks is incorporating the ‘Wilhelm Scream’ into many of the films he works on. This scream is a stock sound clip that he found, which was originally recorded for the movie Distant Drums (1951). Here’s some examples of where the clip has been used.