Released 01 Apr 2016, Last Updated 08 Apr 2022
If you've worked on a film set or recording studio that is pressured by a tight deadline (or headed by lazy producers), you might have heard the term, "We'll just fix it in post" before.
Indeed, the unfortunate bane of many a sound editor's life is background noise or inaudible dialogue that cannot be fixed, thus requiring additional ADR to fix the clip.
So for newer soundies and studio technicians who will be handling a range of recording equipment, what should you be aware of that can - and can't - be fixed later on?
Even if you record using a broadcast-quality microphone, such as RØDE's NTG3, excessive background noise can limit your sound mixer's options, and potentially ruin a scene.
For example, gusty winds, traffic noise, random clatter and other spontaneous and unwanted sound effects could disrupt the dialogue of a scene. Alternatively, people casually chatting or laughing could wreck a wild track or room tone.
This means the production's location scouts need to find quiet, sensible locations to film on, nobody bangs about while you are in the studio and you utilise high-quality microphones for recording.
Despite excess noise being terrible, certain sounds can be taken care of with decent post production software.
Noises with a constant or at least consistent tone are often able to be isolated using a parametric equaliser and a bit of time. For example, DSLR cameras often record sound with a horrible hiss in the background, and a fluorescent light might cause an unyielding hum.
If you can find these frequencies, you can mute them specifically. Most industry software also comes packaged with denoisers of sorts, which may also work.
Sound mixers will curse your name if they are listening closely to a track, only to be deafened by sudden, loud noise that blows out. Though software such as iZotope can do at least a little bit to heal or suppress clipped audio, there's only so many sticky plasters you can put on a wound before it becomes a lesson in futility.
If you record too hot and the sound clips, that information simply won't be there. This shows the importance of wearing headphones, preparing yourself for changes in volume and keeping an eye on your levels to catch them before they turn red.
On a similar note, you can still tweak levels in post to bring the volume down if it is too loud (or indeed to raise it up if the opposite). With a clear waveform, a few keyframes and some time spent listening to a track on a loop, an editor can easily balance sound across an entire project.
It's always best to record high-quality audio during production, however, rather than rely on post to fix everything. This is just another reason you need to invest in the right recording equipment for your sound, as well as think carefully about both location and mic placement.
To end on a last positive note, you can fix, mend or at least cover up bad sound through the use of wild tracks, room tones and foley effects (or ADR, if the worst comes to worst).
Room tone and ambience can be used to fill the gap between lines of dialogue, or to be put under the entire track in order to create a consistent tone in the background (such as traffic noise outdoors). If you think you won't be able to record sound effects on set, adding these in afterward can bring a scene to life.
Sound effects can even work for music tracks, adding an extra element of diversity and realism to help the listener understand the story being told.