Two minutes of extra work on the set or in the field can save you hours of headache in the edit bay. You just need to remember to do it.
Remember MacGyver? With his trusty Swiss Army knife, some bubble gum and duct tape, he could fashion weapons, build flying machines and repair almost anything -- all this, just in time to thwart the bad guys and save the damsel in distress. You have a similar tool at your disposal - perfect for defeating the evils of audio editing. No, it's not gaffer's tape, it's Natural Sound or Nat Sot, for short. Natural sound is often misunderstood or, worse, ignored by many video editors, but it works great covering tough edits and creating a real sense of space. Whether you're shooting standard DV or a high-def project, natural sound can save the day just like our intrepid hero.
I've thought about natural sound quite a bit lately as I've been editing a high-def movie and its associated extras for the DVD. Let me walk you through a couple of typical editing scenarios to explain the importance of natural sound and how to use it in your productions. Scene 63, for example, involves a conversation between two of the lead actors, sitting over a running creek on a low-water bridge. It's a wooded area and there are plenty of birds and insects chirping in the background. As nice as the setting was, the water running beneath the actor's feet was impossibly loud and completely masked all but the loudest of dialog. We went ahead and shot the scene wide to establish the location, then moved the actors away from the noise to shoot the close-ups. After the shoot, I dutifully recorded several minutes of the environment, knowing we'd need it in editing.
The scene starts and ends with the wide shot, but all the dialog uses the medium and close shots from the quieter location. After cutting the scene together, I dropped my natural sound recording into the mix to re-create the environment we'd lost at the new location. With some volume tweaks, that worked great, but there was another problem. During editing, the director decided we should build some uncomfortable pauses in the conversation to heighten the tension. We accomplished this by cutting away to some B-roll. While the close-up location was quieter, it was not silent, and now, there were obvious audio holes in the soundtrack. We patched these by finding some "silence" between takes and using that audio to fill the gaps.
It's easy to record natural sound from your locations. Before the talent arrives (or after they leave), simply roll a minute or two of tape to capture the audio environment. As for microphones, you can use the same mics the talent will use, or use the stereo microphone in your camcorder. If you're interested in recording surround sound, Reason Products and Sony make simple, inexpensive surround microphones that are perfect for this purpose. Capture your audio-only clips along with the other video material and remove the video to create your natural soundtrack. While it's not difficult to do this in most editing software, Adobe Audition has a handy feature called "Open Audio From Video" that simplifies the process dramatically. If the edited video goes longer than your recording, just loop it again and trim any excess. To create smooth transitions, apply a fade-in and fade-out to the ends of your audio segments.
In editing the making-of documentary for the DVD, I ran into similar problems that we quickly solved with natural sound. We shot most of the cast interviews on set, complete with the location audio and an occasional crewmember or two causing interruptions. As with most documentaries in this style, the video consists of the talent describing certain elements of the movie, their character or the process of making the movie. We see the talking head onscreen for a while, and then cut to b-roll to illustrate their chitchat. It's easy to slice the interview into bite-sized chunks, allowing the action to play out, but it leaves holes in the sound that are very easy to hear. I wasn't trying to create an audio environment like the movie and knew that some background music would cover many of the holes. However, the gaps were still there and I had to do something. Rather than use my audio atmospheres, I opted to use quiet parts of the interview to fill the holes. Fortunately, we'd started rolling tape before the interviews and had several seconds of material that would serve as audio Band-Aids.
It's amazing how difficult it is to find these quiet sections when you don't plan for them. Lesson learned: before or after the interview, have the talent clam up for a minute and keep the tape rolling. Using the same microphone in the same location is the best way to save the day in situations such as these.
Natural Sound in Reverse
Let's say you shot an interview or some dramatic dialog in a noisy environment, confident it wouldn't be a problem. Now, you're in the edit suite and it's driving you crazy. I'm thinking specifically of an interview I edited for a friend that was originally shot in a kitchen. Apparently, every segment was bathed in a low whirring of a running refrigerator for the entire 30 minutes of the shoot and every clip had that annoying audio distraction. It won't work every time, but using the Noise Reduction feature of Adobe Audition, or a plug-in for another editor, you can eliminate most of the noise. Since you've read this article and knew to record some natural sound at the shoot, you're set. Go ahead and edit the interview, then load the audio portion and your natural sound recording into Audition. Noise Reduction creates noise template by sampling a segment you define as noise. This is a section of your environmental recording that has just the noise you want to minimize. If you have to find your noise within the interview, you'll be surprised at how difficult it is to isolate just the noise. Fortunately, one-half to one second is plenty for the noise reduction process. Highlight the noise and, under the Effects menu, choose Noise Reduction. Using the preset values as a starting point, click the Capture Profile button. The program will scan the audio and create a noise profile. Next, click the Select Entire File button, and then click OK. After several seconds you should have a freshly de-noised audio track. Listen closely to the new version. Digital noise reduction can cause some strange noises of its own. The new audio may sound strange in places. If so, undo the noise reduction and redo it, using different settings or possibly a different noise sample. Some trial and error is required, but the results are often amazing.
It's Only Natural
Whether you're shooting a movie, a training video or an infomercial, virtually every production will benefit with natural sound. It's a great mix element to reinforce the action onscreen and will cover you in difficult editing situations. It's just as handy (but not quite as fun) as a Swiss Army knife.
Hal Robertson is the cinematographer, editor and entire crew for the independent digital feature, Breaking Ten.