Tricks to Cleaning Up Your Audio
We’ve all been there. Shooting for the entire day, outdoors, on-location, battling the sun, rain, wind, traffic and every other obstacle location shooting can throw our way. All just to capture that perfect shot; that perfect interview or that perfect performance. Now it’s time to head back to the edit suite to dredge through our footage and assemble our masterpiece.
But wait! How can this be? As we view our footage we find that the audio is total rubbish! The dialogue sounds distant with whole phrases being drowned out by unwanted background noise. The natural sound is competing with unexpected voices and shouts from the background. And worse of all, gusts of wind and noisy traffic forever leave their ugly imprint on our audio track.
What happened? Well, put simply we underestimated the most important aspect of producing our video. And it’s not the type of camera or lenses, not the amount of light or even the composition of the shot, but the sound.
The soundtrack is the most important, and ironically the most overlooked aspect of video production. Without a good clean soundtrack your video will likely come across as amateur, cheesy or lacking any impact. Unwanted noise and uneven audio will distract and even drive viewers away. Your piece will simply fail to deliver.
So what could we have done to make our location audio sound better?
Well for starters, just listen. Be aware of what you hear. If there is any distracting rumbling or noises try eliminating them such as shutting off fans or closing a window. If a car horn or overhead aircraft flies by then wait until those distractions pass and then do a re-take.
You may also want to prep your location for clean audio. This is not always an option, but if you can or are allowed try padding the area or room with blankets or sheets to cut down the “audio bounce” or echo caused by room noise. Make sure no electronics or fluorescent lights are causing static interference and ask everyone who is not speaking to keep quiet while recording.
Listening through a good pair of enclosed headphones allows you to clearly hear any distracting sounds while simultaneously previewing your recorded audio.
Do not use your camera microphone. Camera mics are not very good and are usually too far away from the subject. Instead use a shotgun microphone. These microphones are unidirectional which mean they only pick up sounds directly in front while blocking out noise from the side and behind. Pointing the microphone directly at your subject effectively filters out all surrounding noise.
You can also get away with a lav or clip-on mic. These mini microphones are usually wireless and clip right to the subject’s shirt, tie or even hair. This proximity allows for pretty clean audio.
Be sure to record room tone or outdoor ambiance to use in post. Using ambience can sometimes cover up edits and mask unwanted noise. Room tone is also invaluable when it comes to ADR. (Discussed below)
Also consider recording audio onto a digital format such as a hard disk recorder rather than into the camera. Disk recorders mean more channels, which in turn allows for isolated tracks and microphones. These recorders also tend to capture a better quality signal. The downside to this method is that your audio will need to be synced to your video in post. Recording audio right to the camera eliminates the need for sync.
When shooting outdoors it’s vital that your microphone is covered with a windscreen. These fluffy covers effectively block out much of the background noise and wind allowing for vocals or other natural sounds to come through loud and clear.
The last trick is never “over-modulate” or record your audio too loud. Keep an eye on your recording levels and never let the “needles pin“. Over-modulated audio creates distortion that’s virtually impossible to fix. It’s always better to record your audio a little “soft” or quiet, allowing room for the volume to be “boosted”. Of course it goes without saying, if your audio is too quiet then you simply won’t have any recorded information to work with at all. Try to keep the meter levels right around zero.
So let’s say we’ve done all the above and our location audio still needs help? How can we make our dialogue pop? How can we eliminate that awful background noise? How can we create that proper mix of vocals and background ambiance?
Well, I guess you can crack open a professional audio program like Pro-Tools and try cleaning up and “EQ-ing” the soundtrack. These programs are useful at removing hiss and unwanted noise. They can even boost and strengthen vocals creating richer sounding dialogue. However they can’t perform miracles and are best used to clean up minor audio glitches or improve existing “good” audio.
As with most other aspects of production, the “fix it in post” technique will seldom work at restoring a bad audio track. The general rule of thumb with post-production is that you can always make good audio or good video better, but not make bad audio or bad video good.
So if you can’t rely on post-production tools, how can we treat this audio?
Well, we could re-shoot, but that may lead to unacceptable costs and time, not to mention the unavailability or impracticality of re-shooting. (You can’t ask a bride to get married again just because you failed to capture her once in a lifetime moment.)
No, what we really need to consider is audio replacement, sometimes called ADR (additional dialogue recording), looping or dubbing. Put simply this means to edit the existing inferior track with a superior sounding studio controlled recorded audio.
So let’s say you need to shoot a scene containing dialogue of two characters walking down a busy city sidewalk. Well, first off we’re going to find that the traffic and outdoor wind drowns out our character’s voices, even if they are properly miked. So, using our previously discussed techniques for recording outdoors, try capturing the cleanest audio possible. Then, after you have chosen the takes and edited the raw footage, have the performers come into the recording studio to re-cut their lines. The best way to do this is to play back the video of the scene while the performers are listening to the location audio through headphones. The performers can then mimic what and how they originally spoke their lines, but this time their vocals are being recorded in a clean sound controlled environment.
When all is said and done, we now have a clean and isolated audio track that when combined with ambiance, room tone, sound effects and music sounds simply fantastic.
Here’s a good example of what you can do with audio replacement. The following two clips are identical except for the audio. The clips are from a short horror film and show two vampires walking down a busy city street.
The first clip has the raw audio that was recorded on-location. While the audio recorded is pretty good their voices are somewhat buried in the background traffic and sound a bit distant. In addition, the two characters, who are undead vampires, sound too human and natural.
See what I mean? Kind of flat and uninteresting.
So to solve this problem I replaced the raw track with the actor’s re-recorded dialogue. We then punched up their vocals while mixing in city ambiance and some atmospheric music. This gave us a finely tuned soundtrack that’s not only clearly audible, but draws the viewer in.
In fact the trick to good audio is isolating every possible sound in order to “layer” those sounds giving the editor complete control over pitch, volume, EQ and finally the master mix.
Whether shooting on-location, outdoors, in a studio or even creating audio from scratch, paying attention and taking the time to record your audio properly will make your videos stand out and more enjoyable to your viewers.
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