The Sound of a Craving Heart

May 1, 2007 12:00 PM, By Jeffrey P. Fisher

Backgrounds and Room Tone

The hardest problem to fix is distortion caused by overloaded recording levels. If there isn't an alternative take and you are unable to rerecord the distorted lines, you can take the edge off the harshness and make the track more tolerable using EQ to cut 8 to 10 dB between 8 and 9 kHz.

Every location has a sound, called room tone or presence, that gets recorded and is useful for filling in dialog gaps. Because there was no separate room tone included with the project, I had to steal it from ends of phrases and between words.

Background (BG), also called natural or nat sound, shouldn't be confused with room tone. Ambiences, such as traffic noise during a street scene, are usually built entirely in postproduction. Although I created some conventional backgrounds, I also used some nonliteral sounds, such as low rumbles, to underscore emotion and create moods.

With dialog occupying the center position in the stereo field, I gave the backgrounds a wide stereo image using iZotope Ozone 3 (www.izotope.com) to open up the mix. My favorite trick is to combine two mono recordings of different ambiences and hard-pan them. Another approach is to use duplicates of the same sound and hard-pan them, but with one copy offset by half its length.

For Effect

Although sound effects often get recorded on location along with dialog, they are usually not of high-enough quality for the finished movie. Rather, they serve as inspiration and help with synchronization. In this project, only a handful of the original effects remained, and the rest were replaced with better recordings.

You don't have to match a sound to every onscreen action. Focus on covering the obvious sound cues. Generally, when nobody is talking, I add more realism to a scene with sound effects, and I back them off during dialog.

I spent a day auditioning sound effects from my libraries for literal sounds, such as car-bys, footsteps, and doors closing. But I searched for nonliteral sound-design elements as well. Next, I used UltimateSoundBank's X-Treme FX (www.ultimatesoundbank.com) soft synth for layering and audio effects to generate more car-bys, thunder, rain, and general backgrounds. I recorded these MIDI performances — if holding down a key for 20 seconds can be considered a performance — using Sony Acid Pro 6 and then rendered the tracks to 24-bit, 48 kHz WAV files. (DV audio's sampling rate is 48 kHz.)

I also did some field recording with an M-Audio Microtrack 24/96 and a pair of inexpensive binaural mics from Core Sound (www.core-sound.com). I prefer grabbing backgrounds, such as traffic and restaurants, in stereo. I used a Marshall Electronics MXL DRK mic for recording close-up mono tracks, like car doors and footsteps.

By the end, I had amassed about a gigabyte of sound effects. Building such a complex sound toolbox takes time, but once it is in place, much of it can be reused. For example, once you build a location's ambience, you can use it again in subsequent scenes taking place at that same location.

Adding everything to a scene to make it work can take a lot of time. For instance, I spent four hours tweaking minimal production dialog, footsteps, car doors opening and closing, clothes rustling, and a car pulling up, idling, and driving away. It is a completely realistic scene that nobody will notice because it seems natural to the casual viewer, as if it had been captured on location perfectly. Subtle details, such as a little bell chime whenever a door opened in the coffee shop, further enhanced scenes.

One of my favorite sound moments in the film shows a woman waiting in vain for another person while cars whiz by in front of her. I carefully selected stereo car-bys to match the screen action and checkerboarded them on several tracks. Though it was time-consuming to sync every sound element to every onscreen car, the effect was realistic, if slightly exaggerated.

These particular tracks were sent to a single bus, which had a flanger and stereo multitap delay in series, to add an otherworldly sound to the passing cars (see Fig. 2). The scene begins with normal sounds, and then gradually the effects increase as the wait grows longer (see Web Clip 1). There is also a dark, heavy drone to fill in the low-frequency area of the mix.

Another segment that required a lot of effort was when the director had expressed how unhappy he was with the original screams he had used for the final scene. I opted for heavily processed and layered screams to make the scene far more effective (see Web Clip 2).

Music: the Director's Cut

With no budget for underscore, Harrington experimented with Sony AcidXpress and was immediately hooked by how easy it was to come up with music that worked. “I'm no musician, but I had a good feel for the emotion I was trying to convey,” he says.

Harrington's musical sequences were straightforward and unprocessed, so I dressed them with reverb, EQ, doubling, pitch-shifting, volume envelopes, and panning. Though some of Katy J's music came directly from her Stand Still CD, a few tracks were roughs. I placed iZotope Ozone 3 on the music bus to use its EQ, multiband compression, spatial enhancement, and limiting to bring up the volume and give her tracks and the underscore a final bit of sweetening.

It's in the Mix

I premix many of the tracks into stems as I go along, and perform the final mix at the bus level by recording automation in a few passes. I follow the Hollywood standard using a fixed monitor gain that has -20 dBfs, which is equal to 0 VU in the analog realm, yielding 86 dB SPL. The speaker calibration is done using pink noise.

Soundtracks have a much wider dynamic range than music — about 20 to 30 dB compared with a range of less than 12 dB. The dialog averages -27 dB RMS, which most musicians would find remarkably low. There are opportunities for huge dynamic swings in film soundtracks, which is part of the thrill of working on them.

Be sure to check the mono compatibility of your mix, because many theaters have less-than-stellar audio playback systems. I also check mixes at a low volume on small, bass-challenged close-field monitors, such as the Avant Electronics Avantone MixCubes. Referencing my mix on such a system gives me a good idea of what it will sound like on a consumer playback system.

Typically, wind and rain are hard to mix because of their noise components. In the opening scene of the film, I used different rain perspectives (close, far, and midfield) and a lot of equalization (high-frequency boost, low cuts, and carving out the middle mud). For thunder I layered loud, close-up crashes with distant rumbles. Some thunderclaps were actually explosions, and I used reverb with a long predelay to thicken them up.

Some of my bass sounds were routed to a bus with a lowpass filter and pitch-shifter set down an octave. The resulting deep rumble was mixed in at key points for low-frequency enhancement.

Another idea added during the mix happens when a character is awakened by a cell-phone ring. I made the first ring sound as if it were off in the distance, like you might perceive it as you come out of a dream, by soaking it with reverb. The second ring had about half as much of the effect, and the final ring, before the character answers, was dry and up front (see Web Clip 3).

I sent Harrington updates nearly every day, and he made suggestions that were incorporated right away. Because the drive also had the video files, I began making DVDs of the project with the new soundtrack and overnighting them for approval. This became more important when I switched to the newly released Vegas 7 and began using audio effects the director lacked. Near the end of the process, Spotted Eagle added his invaluable insight into the mix, and the audio portion of Craving was finally complete.

All that remained was some video work, such as color correction, and the final swap of proxies for the high-definition HDV media. Spotted Eagle handled the video tweaks while I pulled the project file together for the final rendering, which took more than six hours. I also authored the initial DVD for film festivals.

In Focus

If you do sound for picture, you have to learn to live with the fact that most of your work goes completely unnoticed. As the saying goes, “Nobody leaves the theater whistling your sound effects.”

Despite the amount of tedious grunt work involved in audio postproduction, creative sound design and mixing can make the process fulfilling. Every project has a unique set of challenges that force you to employ every ounce of your knowledge and creativity. Finally, when you see and hear your work in a darkened theater and experience the audience's reactions, you know all that effort has paid off.

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Jeffrey P. Fisher's latest book is Soundtrack Success: A Digital Storyteller's Guide to Audio Post-Production (Thomson Course Technology, 2007). Learn more about his work at www.jeffreypfisher.com.