Lightsaber Sound Cookbook

Ben Burtt's lightsaber sound effect, considered by many to be the greatest Star Wars sound effect of all time, is comprised of just a couple of steady humming sounds. The way they are combined, however, results in something spectacular. This is typical of many sound effects in Star Wars, and a characteristic of Ben Burtt's style. He often constructs his effects from diminutive elements, layering and sequencing simple sounds into an extraordinary alloy. Notably, since he builds sounds up from such simple parts, he retains control over every nuance of the mixture and therefore his sounds are also bestowed with a remarkable range of expression.

Unique to Ben Burtt's lightsaber sound design is a rather unusual recording technique. Wielding his microphone like a sword, twirling and swiping it in front of a speaker, he recorded real movements, turning the laws of physics into a signal processing system. This molded the waveforms into expressive gestures, as if he honored a vibrating larynx with a mouth to form vowels and consonants. Through this meticulous research and experimentation, the sound of lightsabers began to take shape and, expertly, the technique that brought it to life was hidden deep within its own brilliant illusion.

In this tutorial for creating original lightsaber sound effects, I have not only attempted to unearth Ben Burtts's design, but I have also embellished it with my own ideas, so this is a mixture of detective work, speculation and creativity. Some of you will use this tutorial as inspiration for new sound design techniques but I think the majority of you are interested in simulating lightsabers for your projects. Whatever the case, I suggest that the first time you experiment with it you do not get too wrapped up in trying to get a specific sound. The important thing is to get a good feel for the entire process, learning how the different steps contribute to the end result. After your first try, you will have a much clearer idea of how to proceed with the tone and texture of your lightsabers.

This tutorial is slightly advanced and assumes that you have prior understanding of multitrack recording and editing with such digital audio workstations as Protools, Nuendo, Sonar, Ableton or Vegas. You should also understand how to use audio plugins like equalizers and dynamics processors. It is not absolutely necessary that you own a shotgun microphone but in order to do accurate lightsaber emulations you should buy, rent, or borrow one. Refer to the glossary at the bottom of this page if you are confused by the tutorial's terminology.

When asked to come up with the sound of the lightsaber, Ben Burtt decided to use the humming sound of an old film projector. The projector housed two motors which vibrated at different frequencies, together producing a slow harmonizing pulsation. The interaction of these two tones is intrinsic to the way lightsabers sound when being swept around (lightsabers oscillate at a low frequency when idle and burst into a higher frequency when moving). These abrupt shifts in frequency are analogous to Doppler shifts of fast moving objects, therefore it sounds very natural for the lightsaber to change frequency when in motion. The projector motors sounded warm and smooth, providing a lot of energy and low end girth. However, he wanted some high end electrical vibrance. In order to give the lightsaber sound an electrical quality, he mixed in a sound which he discovered when passing his microphone in back of a television set called electromagnetic interference (EMI). This sound was emitting from the television's cathode ray picture tube (a.k.a. "CRT screen"). Presumably, he took this waveform and dropped it slightly in pitch to be in unison with the two motor hums, one at about 98Hz and the other at about 90Hz. Two separate oscillations were created: one at 98Hz consisting of the high motor hum and EMI buzz, also one at 90Hz consisting of the low motor hum and EMI buzz.

These waveforms are the main components necessary to create the lightsaber sound effect. Like me, you probably do not have the precise model of some obsolete film projector that Ben Burtt used to get the hum, in which case you can actually use the vibration of an old electrical transformer. Alternatively, you could use a synthesized triangle wave or filtered sawtooth, adding some light chorus to give it movement. For the buzzing sound you should not have too much trouble procuring an old television with a cathode ray picture tube. If you absolutely can not get one, you could synthesize the buzz with a bright sawtooth or pulse wave. If you are attempting to create a more authentic lightsaber sound, you will be much better off not using synthesizers. One of the reasons that the sound effects for Star Wars are so unique is that synthesizers were used very little, which gave the sounds an organic quality. By recording materials and physical reactions, sounds have a more natural and realistic character.

If you want to create an accurate rendition, I highly recommend using the movies as a reference. Both the Darth Vader vs. Obiwan duel in Episode IV and the Luke vs. Darth duel in Episode V are good; each of these scenes feature the original lightsaber sound effect without background music.

To emulate Ben Burtt's projector motor recordings, try capturing a humming transformer in an old radio, an electric razor, an engraver or any other vibrating electronic device. You will need to record it with a decent condenser microphone or possibly a contact mic so that you get a loud clean signal. I suggest moving the device or your microphone around a bit so that the sound transforms a little from moment to moment.

Pressing the device against another object may amplify and change the character of the sound substantially. For example, if an engraver sounds too high pitched and raspy, duct tape it to the inside wall of a thick plastic tote and put the cover on.

I had good luck with an old electric fan, feeding it just enough power so that the blade would not turn, which caused the transformer in its base to hum loudly. To induce some extra motion into the sound, I rotated my microphone around closely in front of it. Two one minute recordings were made which I had to bring down in pitch. Here in North America, transformers hum at 120Hz and in Europe 100Hz so if you are using transformer hum you will have to tune your oscillations from either one of those frequencies down to 90Hz and 98Hz accordingly. There may be some hiss in the recording so use noise reduction or cut the high end a bit. Regardless of the sounds' origin, you should end up with two different hums, one at 90Hz and one at 98Hz, each at least one minute long.

If your humming sound is too thin or does not have enough high-end, you can reinforce it using equalizers or a re-synthesizer such as Chameleon 5000 or Doppelmangler. It is important that you end up with a hum that sounds powerful and lively. This reinforcement should occur after you tune your recordings to the proper frequency.

Later you will create variations of this sound called accent hums, useful for dramatic action. If you want to tackle these now, see "Special Sounds" below. To make this tutorial go faster, I recommend making these sounds after you have created and tested the basic ones.

For the buzz sound you should use an old television with a CRT screen, holding a microphone against the back to pick up the interference. It is possible to get this interference from a florescent light bulb but I found it to have too many crackly sounds and weird harmonics (not to mention that it also energized my Zoom H4 with an electrical charge that erased the card and nearly blew my fingers off). Many mics are very good at blocking out electromagnetic interference. A Rode NTG-2 shotgun mic pressed sideways against the back of a Zenith 25 inch television produced a very loud signal with just the right tone. However a Rode NT-1 barely picked up any interference at all, neither did the Zoom H4's built in mics. I read in Wikipedia that Ben Burtt may have recorded the EMI from an unshielded cable but I believe this is false because doing so produces a complex modulated tone unlike the lightsaber. You will, of course, pick up other sounds in the room and most likely this will include the high pitched squeal of the cathode ray which is around 15.7KHz. If your ears have lost high-end sensitivity you may not notice it, in which case you can drop the sample rate of the recording to hear it. Keep in mind this sound will cause headaches for people with good ears. Use a narrow notch filter to get rid of this oscillation.

Once you have recorded this sound and removed the squeal, drop the pitch to 90Hz and create a second version at 98Hz. Again, use noise reduction to clean up the completed waveform.

You should now have 4 waveforms: A high hum at 98Hz, low hum at 90Hz, high buzz at 98Hz and low buzz at 90Hz. Create 4 tracks in your audio workstation, one for each sound. Now you can work on the tone of your lightsaber and here is where the films will start to come in handy. Locate a section of a Star Wars film where you can hear an idle lightsaber sound (a part where the lightsaber is powered up but not swinging) without dialogue or music, then create a reference audio file and load it into a 5th track on your audio workstatation. Solo/mute it when you need to compare your own lightsaber sound to the original.

Now turn on the two 90Hz sounds, creating a nice balance of the hum and buzz with a lot of body and growl. This is the bottom end of the lightsaber sound which provides the fundamental frequency and most of the girth. You do not need to get this perfect yet, just mix it to taste for now. When you are done with this, turn these two sounds off and do the same for the high frequency sounds, this time mixing in just a very faint bit of the buzz so that the hum sounds more bright than it would by itself. This is the high-end sound that will most often be heard when the lightsaber swings. For now on I will refer to the low end, 90Hz mixture as the "low oscillator" and the high end, 98Hz mixture as the "high oscillator". The oscillators are the sounds that will be fed into the speakers later on.

Next, turn both the high and low oscillators on and listen to the entire mixture closely. Compare it to your reference, making any necessary volume and equalization adjustments for each track. You are not trying to emulate a moving lightsaber yet but just the tone. The movement effects will be created next. If you are way off base, you may want to go back and re-record or resynthesize the hum or buzz. Again, try not to get too bogged down with getting the tone right before you are familiar with the whole process. Just give yourself something to work with as you proceed to the next step.

Even if you do not have a microphone and speaker, by mixing your oscillators together in your DAW you will end up with a decent lightsaber idle sound. This is the best way to get started making lightsaber sounds and it is also a good way for you to rehearse your oscillators, making sure that they will give you a nice tone. You may even decide to use this sound in your finished lightsaber duel, using it as a foundation to build from or as a filler sound. I found that blending in a premixed idle here and there adds a bit of extra dimension to the final mix.

In your workstation, add an effects plugin to each of the four tracks that will make the volume go up and down very slightly. Amplitude modulation is featured in tremolos, choruses, flangers, and panners and many other types of plugins. I used Waves Mondomod, disabling frequency modulation and stereo rotation to get a slow and subtle up and down modulation. Keep the effect slight, you just want a touch of motion in the sound, not a rhythm. Because the sounds all have slightly different harmonics, when they independently rise and drop in volume the mixture becomes full of textural motion. Listen to your reference file and try to mimic some of the fine textural movements you hear. Make each plugin modulate at a slightly different speed and even add a few more of them in series for each track to create more complex modulation. You should end up with a subtle and irregular shifting of the high-end that makes the lightsaber sound breath with life. It should now start sounding a lot more like a lightsaber. When you are happy with the results, render out a minute or so and save it.

Here is a premixed lightsaber idle created with transformer hum and picture tube buzz:

Here is where things get fun, albeit a little more tricky. You will need a few more tools to do this right, including a shotgun microphone, a speaker, headphones, a good sound card and a new reference file (one that includes swiping sounds). A long shotgun is preferable, one having a narrow acceptance angle, but if all you can get your hands on is a short or medium length one (like me) there is a way to make it work which I will describe below. The speaker should have some low end but does not need a lot of highs. A full range cone is optimal but a two-way speaker will also work (that is what I used in this example) but you may have to keep the microphone further away from the cabinet to get a nice tone. You will need to play sound through the speaker and simultaneously record and monitor the microphone input. Therefore, you will need a soundcard with multiple outputs, preferably one that includes line level outs and a dedicated headphone output. A good alternative to this is to connect your microphone to a mixer, send the mixer output to your sound card and use the headphone output on the mixer to monitor the signal coming into the mic.

Set your speaker up in a quiet area, clear of obstacles, at about chest level and play the low oscillator sound through it. Turn off effects because you are going to reproduce the effect physically now and do not want to include processors in your recording. Your headphones should only be monitoring what is coming in through the microphone. The microphone signal should be going to a record track on your DAW. Before you make the recording, just get a feel for the way the low oscillator sounds when you wave the mic around in front of the speaker, listening for problems. You may need to wrap a cloth over the microphone or use a shockmount to reduce handling noise. Also, consider taping the cable to your arm so that you do not bump or yank it. Listen for any extraneous sounds such as fan noise from your computer, breathing, footsteps, or cloth movement. Try to get rid of these artifacts because they will plague your lightsaber sounds.

Point your microphone at the speaker and adjust the input level so that you are not getting any distortion when it is capturing the full signal. Now move the mic around, pointing away and then directly at the speaker. Pass it by the cabinet quickly, then slowly, getting a sense for how to control the swinging sounds. Try pointing the microphone away from the speaker most of the time at an angle that provides the most rejection because you only want the sound to rise up now and then. Listen to your reference and try to get the pacing and movement of your swipes similar to what you hear in the films. Remember that you are only hearing one half of the sound now, just the low oscillator. When you think that you are ready, make a recording. Perform a wide variety of movements so that you have a lot of material to choose from when you edit. A good lightsaber sound library will include lots of variants on the most useful sounds. Do the same with the high oscillator and save your recordings to separate files.

If you are creating sound for picture, you can load the video into your DAW and perform your movements to it. Personally though, I think this complicates things too much. If you create a library of idles and strokes with plenty of variations, you should have what you need to edit any duel together.

I am not sure if Ben Burtt recorded the high and low oscillator sounds in one pass by waving his mic around in front of two appropriately placed speakers. My Rhode NTG-2 shotgun mic does not have enough side rejection to allow this to work (the sound from each speaker would mix together too much). Therefore I have to record each oscillator separately. This works fine though and it may even be better because you can mix them together more carefully during the editing process.

Accent Hum:
When a lightsaber swings aggressively or when tension is rising, the oscillators should sound more fierce and electrifying. This can be achieved by creating accent hums, which are basically just different versions of the high and low oscillator. To create them, you can either make processed versions of your hums or synthesize new ones from scratch. A quick and effective technique is to simply run your hum through a distortion plugin such as iZotope Trash. Trash will really allow you to change the personality of your lightsaber sounds and is especially good at energizing weak sounds. It is not absolutely necessary to record the accent hum in motion with your microphone. During the edit-to-picture stage, you can just layer some accent hum in here and there using volume envelopes.

Power Up/Down:
For the blade open and close effects, you can be very creative as these vary quite a bit in the films. I found that the sound of a solid fuel rocket launch is a good starting point, as is a credit card sliding across plastic laminate (such as Formica), or even chalk on a blackboard. If you bend the pitch of these sounds upward it sounds like a lightsaber blade opening and the same sounds in reverse work for closing. In fact, any smooth "pssshhh" type sound will work and I have no doubt that, with a bit of processing, you could even use your mouth to create it.

Clashes:
For the blades colliding, look no further than electrical zaps. You can design these effects with microphones, synthesizers and effects processors. However, since this topic is so complex, it will require its own web page. Therefore, unless you already know how to create these sounds, I am going to recommend that you use commercial sound effects from such retailers as sounddogs.com. If you just can not cope with that (which I sincerely hope) it is possible to create these sounds using car batteries. Check out this page on epicsound.com for more information.

Before you convert your recordings into a sound library, listen closely to what you captured and identify problems. The main trouble I had was one caused by lack of side rejection in my Rhode NTG-2 shotgun microphone. It is not a long shotgun which would have done a better job of reducing off-axis sound, enabling me to make more defined strokes. In order to remedy the problem, I ran my recordings through an expander, which is basically the opposite of the more popular processor known as an audio compressor. Whereas a compressor makes loud sounds quieter, and quiet sounds louder, an expander makes loud sounds louder and quiet sounds quieter. In some ways, adding this increased dynamic range to my recording simulated the way a long shotgun microphone would have behaved, making the off-axis sounds very quiet and the on axis sounds loud and present. If you do not have a long enough shotgun or would simply like to enhance your dynamic range, this is a decent solution. You can do this by making the ratio value on your compressor less than 1:1. I used a ratio of 0.5:1 so that when the input signal exceeded my threshold setting the output increased in volume by 50 percent. Of course, I had to reduce the output volume considerably to prevent the signal from clipping. This effectively made the oscillators sound quiet when the speaker was off-axis and at full volume when the speaker was directly in the microphones path. The end result was that my strokes sounded more punchy.

A symptom typical of directional microphones, muffled off-axis frequency response helps to create a more faithful lightsaber emulation. This problem becomes useful, transforming the oscillator sound with a lowpass filtering effect. When the speaker is on-axis the filter is open and off-axis the filter is closed, giving the lightsaber, for lack of a better description, a "wrroww" filter sound. The more side rejection the microphone has, the more pronounced the effect. If you are not getting enough of this, you can use what is called an envelope filter, which is basically a lowpass filter with a cutoff frequency controlled by the input level. A 12dB per octave filter (this is also called a 2-Pole filter) works well. This functionality is included in such plugins as PSP Nitro, a modular VST plugin with powerful envelopes and several 2-Pole filter types. You can perform this process to individual samples, but I suggest adding the effect to your stroke tracks during the mixing and editing stage. (If you try this and the filtering is too severe then adjust the plugin's mix level to 50 percent or less.)

You may want to perform equalization on the recordings. I used a speaker with excessive low end, an Event 20/20 Bas. Therefore I had to reduce the bass on the recording a bit. Also, my recordings resonated in the midrange so I notched out the offending frequency with a parametric equalizer. The Event's built in amplifiers sound noisy at close proximity which made my swiping sounds hiss so I got rid of the offending noise with Waves X-noise.

Following all of this prep-work, cut your recordings down into a well organized assortment of shorter samples. You should have high strokes, low strokes, fast strokes, slow swelling idles, subtle flicks and all sorts of sounds that you created by twirling the microphone around. Whatever you created, use a naming convention that will make it easy for you to find sounds of a certain character. If you are making sounds for different types of lightsabers, such as battlestaffs, lightwhips or short sabers, consider separating them into different tone sets. Also, every time you make recordings for lightsaber sounds, you will undoubtedly come up with sounds of a completely different character. Therefore you may also want to create sets based on subtle differences in tonality.

In the next step you will combine your samples into a composite lightsaber sound. Create a new project in your DAW with a track for each sound type. If you are just experimenting with this for the first time, you may only need three tracks: idles, strokes, and accents.


	Steinberg Nuendo (pictured) is a great DAW platform to create lightsaber duel sounds on. If you are new to audio editing you might consider Sony Vegas, a workstation far easier to learn. Both of these programs feature video import.

First lay down some samples from your library, getting a feel for how the different sounds can be used together by mixing them, putting them in series, dragging them forward and backward in time, etc. I find that it is best to start with power ups and idles, then work in the strokes, then the accents, and finally the clashes. These are recommendations only, and should not keep you from recognizing your own techniques. After playing around a bit, you may realize that you are lacking enough variations on some sounds, in which case you should flesh out your library more.

Remember to refer to your film reference, listening to and watching the way lightsabers sound when swinging around in a battle sequence. Try to identify the idle sound and the high and low strokes, paying close attention to the way these sounds interplay. Sometimes when a lightsaber starts to swing the high oscillator resonates to full volume and halfway through the swing the low oscillator takes over. This can be achieved by superseding a high stroke with a low stroke. The pitch of the oscillators often go above or below their default frequencies, especially during suspenseful action, creating discord and edginess. You can create this effect simply by adjusting the pitch of certain samples up to plus or minus a semitone or even more. In an idle state, the two oscillators are fairly balanced but occasionally the low oscillator intensifies, especially when the duelists approach each other. To do this, simply increase the level on your low idle or mix in an aggressive low accent hum.

Obviously, the mix should sound cohesive, that is, one should not know that they are listening to layered and sequenced samples. The high and low oscillators should form one composite sound, rather than sound like two different sounds on top of each other. Sometimes, the best way to achieve this is to see-saw between them; if the high oscillator gets louder, drop the level of the low oscillator and vice versa. Also, try not to layer high and low strokes too much, but instead flip-flop between them.

When you are creating the sound of two lightsabers, you need to be careful not to layer too many sounds together. For example, if you had 2 high strokes or a high and a low stroke sounding at the same time (1 sound for each lightsaber in motion), it can sound cluttered. In order to give the mix punch and clarity, use the least amount of sounds possible and avoid layering like-sounds. If two lightsabers are swinging at the same time, the sound of one stroke may do.

For added realism, especially with indoor battle scenes, you should apply some reverb to the mix by setting up an effects send on each track. Generally, the clash sounds will require the most reverb. Spreading the different sounds to the left and right also helps, as does a bit of stereo panning motion on the strokes. Ultimately, when your sounds are synchronized with video and mixed in with foley, special effects and music, the genuineness is hugely intensified.

Once your lightsaber sound library is fleshed out and you know how to use it, the process of mixing a duel is fairly straightforward. Most of the work should go into the library creation so that when it comes time to mix, you are able to control the sounds as expressively as a musical instrument.

Below is a short lightsaber battle I created by following the various steps listed in this tutorial. I first made recordings of transformer hum and picture tube buzz to create oscillators. Next, I used a microphone and speaker to transform the oscillators into stroke sounds. I then assembled the recordings into a lightsaber sound libary and finally mixed together the battle.

Hum: The fundamental sound of the lightsaber which is combined with the buzz sound to create high and low oscillators. This sound can be created with recordings of vibrating Electromechanical devices or synthesizers.

Buzz: A sound that is mixed in with the hum to make it more electric and vibrant. It is created with either recordings of electromagnetic interference from a cathode ray picture tube or with a synthesizer.

High Oscillator: A 98Hz waveform consisting of the hum and buzz mixed together. This sound is sent through the speaker and recorded with a shotgun microphone to create strokes.

Low Oscillator: A 90Hz waveform consisting of the hum and buzz mixed together. This sound is sent through the speaker and recorded with a shotgun microphone to create strokes and idles. The low oscillator is prominent in idle sounds.

Stroke: The sound of a lightsaber in full swing. Strokes are usually at either 98Hz (high stroke) or 90Hz (low stroke) but are often somewhere in between. This sound is created by recording the high and low oscillator sounds with a shotgun microphone.

Accent Hum: A variant of the basic hum that is more intense and perhaps even distorted sounding. Accents are mixed in with strokes and idles to make the lightsaber sound more aggressive. This sound can be created by running the high and low hum through a distortion plugin or with a synthesizer.

Idle: The sound of a lightsaber that is powered up, but fairly motionless. The idle sound is usually comprised of a mixture of the high and low oscillator sounds, either recorded with a microphone or mixed together in the DAW.

Clash: The sound of two lightsabers colliding, usually created with electrical zaps.

DAW: Abbreviation for Digital Audio Workstation, a multitrack audio editor. Examples include Protools, Cubase and Nuendo.