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Magical Sounds

Feb 1, 2006 1:00 PM, By Blair Jackson

Creating the sonic Harry Potter universe—again.

Web-Expanded Version

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Potter Sound Secrets

Next month's DVD release of Harry Potter and the Goblet of Fire gives audio professionals a chance to take a closer look at a great accomplishment in sound effects. Although passed up for Academy Awards in visual effects and sound, the fourth film in the mega-grossing fantasy series was a tremendous undertaking from a technical standpoint. Matching the mind-boggling visual effects of the film — complete with dragons, underwater scenes, and scores of magical components — was a challenge principal sound designer and co-supervising sound editor Randy Thom was more than ready to take on.

An Oscar winner last year for his work on The Incredibles and The Right Stuff 10 years earlier, Thom was one of just a small handful of people who worked on Goblet of Fire's post. Thom also supervised the second Potter film, Harry Potter and the Chamber of Secrets, and was an Oscar nominee for such diverse movies as Star Wars: Episode VI — Return of the Jedi, Cast Away, Contact, Backdraft, and The Polar Express. At his sound design suite at Skywalker Sound in Marin County, Calif. (north of San Francisco), Thom also worked on effects for the forthcoming computer-animated films Monster House and Ice Age 2.

When asked if he had to respect some of the audio conventions established in the first three films of the series when working on Goblet of Fire, Thom says, “Definitely.”

“You have to be a little careful about reinventing the wheel, coming up with a set of magic sounds for actions that are similar in a previous movie,” he continues. “You wouldn't want them to sound absolutely, completely different than the movie you're working on. On the other hand, magic is magic, and you don't expect things to be the same all the time, so we do have quite a bit of latitude to change things, also. One of the tricky things about the Potter movie, like a lot of the movies we work on, is you have all these magical things going on — spells and wands and fantastic creatures — and they still need to sound organic. It can't sound like it's electronically synthesized and belongs in a space movie. So my job, then, is to come up with a palette of sounds that suggests magic but still is grounded in more-or-less real-world sound. So in this one I tended to use, as a starting point, things like thunder and wind, for instance, both of which can sound kind of musical and magical, but are very familiar sounds and organic real-world sounds that people can relate to.”

Thom likes to record as much original material as he can for each film he works on, but also taps into his extensive personal archives and other sound collections available at Skywalker Ranch. In the case of the thunder recordings that became the base of a number of effects in Goblet of Fire, Thom reveals, “There's this blind guy who lives in thunder country named Tad Staples, whose entire life revolves around thunder. He gets someone to drive him out when the storms are happening and he records thunder. We've been buying thunder recordings from him for quite a while, and I've also recorded a few over the years myself. Then, obviously, we're constantly fiddling with them — playing elements backwards and combining them with other things to make new sounds — but it's always nice to have a new crop of thunder sounds every once in a while so you can keep things sounding as fresh as possible.”

At this point, Thom is doing most of his sonic manipulation in Digidesign Pro Tools. “I've never been a big sampler person,” he says. “I don't have anything philosophically against them; I used a Synclavier for a while, and an Emulator, but I've never really relied on those. These days I tend to just drag sounds into the edit window in Pro Tools and use plug-ins and basic editing techniques and volume modulation to get the effects that I want.”

Thom and co-supervisor Dennis Leonard, with whom he's worked on 10 films, spent about eight weeks designing, gathering, and editing sounds at Skywalker. Then, they headed over to England to work with a post crew at DeLane Lea Studios in London's Soho district. A month into their London sojourn, they brought another top Bay Area sound editor, Doug Murray, over to help out on effects production.

“The English sound crew did a wonderful job,” Thom says. “Andy Kennedy, our senior English effects editor, really made the dragon sequence sing. And Tom Johnson, who used to work at Skywalker and now works mostly in Dublin, Ireland, mixed the effects magnificently.” Like Skywalker's principal mix room, DeLane Lea's Theater One is equipped with a Neve DFC mixing console.

The main storyline of The Goblet of Fire revolves around the Triwizard Tournament, which pits Potter against other magic students in three perilous tasks. Each of these set pieces required a tremendous amount of creativity from the sound design team to match the fantastical CG effects.

In the first challenge, Potter battles a very ornery dragon. How did Thom deal with its fearsome vocalizations? “One thing we did that was useful was to record my voice,” Thom says. “I almost always use my voice — it's cheap talent — in any kind of creature vocal. We recorded me at 192kHz and I tricked Pro Tools into thinking it was 48kHz or 96kHz, and if you do that you get a much cleaner, fuller pitched-down sound than you do if you record even at 96kHz or 192kHz and then use something like the [Serato] Pitch ‘n Time plug-in to alter it. The illusion is that there are more high frequencies there even when you're playing something back at one-quarter pitch. For certain kinds of program material, it can sound almost like a recording that hasn't been altered at all, and you rarely get that effect when you pitch something down using a plug-in.

“Then we'll take that sound and combining with the usual cast of characters — pigs, horses, and big cats. … I love doing creature vocals and I detest doing creature vocals. It's a real challenge to come up with something that sounds fresh and new and organic and huge, and also varies from moment to moment. So it's a combination of various real-world animal recordings and my voice — most of the growling in between the roars is me.”

As for the dragon's immense, leathery wings, Thom says, “Some of that came from actual wings that I had recorded. We found a taxidermist that had Canadian geese and other very big birds, so there were these wings that were obviously very stiff, since they were taxidermied, but the great thing about them is you got the real sense of feathers — which doesn't necessarily apply to something like a dragon, but it's a great sound, that swish of air through feathers you get when you flap it in front of a microphone. Then, if you combine that with big rugs or tarps, doing a similar thing — you get two or three or four people and hold up this big rug and sort of wave it and flap it through the air — you're pretty close to the kind of physical scale that you need to do a dragon's wing.” Thom's current favorite field effects recorder is the Sound Devices 722 digital unit.

The second challenge occurs underwater, in a lake on the Hogwarts grounds. “Underwater sound is one of those movie conventions that defies the laws of physics,” Thom says, “because actually when you're underwater you hear more high frequencies than when you're above the water, because water transmits sound better than air does. But the convention that people are used to is that sound underwater is muffled, so if you try to do anything else, people don't believe it. Actually, a lot of the underwater [movement] sounds you hear [in the film] is just swishing hands through water. I've found that you can get more interesting sounds not necessarily recording under the water, but by recording at the surface of the water and moving your hand, your foot, or a stick or whatever, swishing it around in the water so it's partially submerged and partially out of the water, and then EQing it; I'll roll off highs. Sometimes, you get some interesting acoustic phasing as your hand moves through the water, or maybe you have a really interesting beginning of one swishing sound and then you edit to the end of another swishing sound.”

In the film's climax, following the completion of the third task, Harry and the evil Lord Voldemort lock in battle with their wands in a dark, forbidding graveyard — great arcs of light collide with incredible force, as sparks fly and what seems like a fiery molten profusion lights the night sky. “The first thing the director told me, which I anticipated, is, ‘We don't want it sound like Star Wars,’ yet in some ways it has some similarities to a laser sword fight,” Thom says. “These wands are creating a lot of heat, so you have white-hot stuff dripping and flying everywhere. We used a lot of thunder and lightning sounds in that sequence — some of it is more or less normal thunder, some of it very manipulated, in terms of maybe having all of the lows EQed out of it, and I'd combine that with some really high-frequency crackly thunder, with some Jacob's ladder-type electrical sounds, to make it sound even more vicious than normal thunder. You want to convey that this is a life-or-death struggle, but the scene goes on for a while, so you also need to keep it as varied and dynamic as possible.”

In the end, the sound designers faced challenges nearly as daunting as the ones that faced Potter: For more than two and a half hours, it's a sonic trip to another time and space where little is as it seems and there's always danger around the next corner.

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Potter Sound Secrets

Randy Thom and co-supervising sound editor Dennis Leonard unblock more sound secrets of Harry Potter and the Goblet of Fire.

On the use of nearly inaudible sound elements to heighten tension:

Leonard: "There are a lot of subliminal sounds in the film. One thing I did that was interesting is I created a number of low-frequency sweeteners—these really low-frequency punctuations—using a program called Trilogy [by Spectrasonics]. What I ended up doing is an old analog synth trick: turning the resonance of a filter all the way up—and I was using a string bass sample—and then sweeping the center frequency very close to the frequency of the actual fundamental note I was playing on a keyboard. What you end up with is these anomalies where nine out of 10 of them are going to be distorted, but in one out of 10 you get this tremendous amount of air movement; I was jokingly calling them barometric events, because they move so much air. I used those for some of the spells' wand action. They're inaudible, but you sense them through the subwoofers. It feels like a disturbance in the atmosphere. Anything below [listenable] audio people find very disturbing." Leonard also developed subsonic information for the appearances of "The Dark Mark," creating a 19Hz pulse out of wind and other rumble samples played simultaneously on a keyboard.

On the magical maze in the Triwizard Tournament:

Thom: "The maze is one of my favorite sound sequences because it has so much dynamics. We get to be really quiet in certain sections. When Harry first goes into the maze, I said, 'How about if we go to absolute silence there, like this hedge that's between him and the people in the [stands] and the band is soundproof wall. So there's no sound there for a moment or two,' and I love that—going from lots of sound to no sound. I think it has enormous dramatic potential when you do that sort of thing in the right context.

"It was also fun doing whispering sounds for the maze. You never see what it is that's whispering, but you assume it's spirits of some sort. Some of that was done in ADR in loop group form, and some of it was various whisper recordings I've made over the last year or two."

And how about those hedges in the maze that grab at people and crash into each other with no notice, closing off passages of possible escape?

Thom: "That kind of scene is fraught with danger in sound editing because if you started doing a sequence like that by treating it literally—and just finding big bushes and bashing them into each other—it wouldn't sound interesting; it would be noise. Especially in mid-range and high frequencies, it can turn into pink noise. So we started on that scene with very little of that kind of stuff. Instead we made it more tonal and gave it as much character as we could. There's a plant that grows at Skywalker Ranch that has a stalk that's hollow and when you break it or crack it or slit it, it has an almost vocal quality to it, because it has this cavity that changes in shape as you smash it or twist or break it. So you twist and break enough of them that you get enough moments that are useful, and that was an important element in that hedge sequence also. Then you can add some of the other kind of more obvious [plant crashing sounds]."

The sounds of underwater creatures in the second task:

Thom: "The Merpeople had two cries: one is a kind of mournful cry, which was a whale recording pitched up quite a bit, and the other was a kind of frightened or aggressive cry which is a combination of human voices blended in an interesting way.

"One other specific sound I could mention is the vocal sound for the Grindylows—the little squid-like underwater creatures. Those came from a dog named Choochi. A guy ... here at the Ranch recorded this dog which had an incredible voice that was almost human sometimes. In fact, I tried to use it in War of the Worlds, but [director Steven] Spielberg decided he didn't want the Martians to have voices. So I got to use some of that experimentation for Harry Potter. The voice has an almost whimsical or comical element to it, and I was a little afraid that Mike [Newell] and editor Mick might think it was too comical, but they actually liked it."

The mysterious Portkey, which magically transports wizards through space:

Leonard: "That's something Randy built, and it is essentially winds that were manipulated with a plug-in called GRM Tools, which has an excellent Doppler program, and varying the speed of the repeats."

And finally: Making big crowds out of small groups:

Leonard: "One of the big issues we faced is that all of those scenes where there were big crowds, those were mostly CG scenes and we didn't have the huge crowds you see onscreen. The Qidditch World Cup was almost all CG, so we had to come up with the chants and the general crowd sounds. And [in the Triwizard Tournament] where you saw a stand with kids, only about half that was kids, and the rest was CGed-in kids; plus it was shot inside, so it wouldn't have sounded the way we wanted for outdoor scenes.

"So we found a location two-and-half hours outside of London and took five adults and about 45 kids—including about a dozen ringers who were voice-talent kids from London; the rest were from a local school's drama department—and went to this abandoned RAF base that was out in the wide open and spent an entire day recording all the crowd material in 5.0 [L-C-R plus rears; no sub] on a portable Pro Tools rig. We came up with a spacing of the left, center and right mics which is the average space behind the average screen in a multiplex, to try to capture all of the time domain image nuances that you would get. Randy recorded MS, and I recorded a shotgun walking through the crowd as we did each cue, and we had an eagle up there with a bird handler to chase away birds so we wouldn't get any intrusion. It worked out really well; it was a great environment. I believe that the more you can do to capture natural sounds in a good environment, the more vibrant the soundtrack is."

© 2008 Penton Media, Inc.