Ben Burtt, sound designer of the Star Wars films, details how he created the iconic sound of lightsabers in this vintage interview.
The lightsaber hum is one of Burtt's favorite sounds, he says. Inspired by Ralph McQuarrie's concept paintings featuring lightsabers, Burtt said he could "hear the sound in his head." At the time, he was still a graduate student at USC and was working as a projectionist. The old projector had an interlocked motor which, when idle, made a "wonderful humming sound." Burtt recorded it, and it became the basis of the lightsaber sound. But it wasn't enough -- he needed a buzzing sound, and he actually found it by accident. Walking by television set with a live microphone, the microphone picked up the transmission from the unit and produced a buzz. Burtt loved it, recorded it, and combined it with the projector motor, creating a new sound that became the basic lightsaber tone. To achieve the aural effect of a lightsaber moving, he played the hum out of a speaker and waved a microphone by it; doing so created the fascimile of a moving sound, and in this case, the sound of a Jedi or Sith wielding a weapon in battle. In this video, Burtt is seen using this technique to match the strikes in Luke Skywalker's duel with Darth Vader in The Empire Strikes Back.