Post Audio Cleaning

thefilmaddict

thefilmaddict

New member
I shot my film. I did the best I could capturing good audio in the field, but some of the sound is not pretty.

Any ideas on how to clean up the audio as one person talks with very little ambient noise and another person talks and the background is very noisy. This is because the first actor was loud and the second one was quiet (making me crank up the second actors levels in post, which of course brings up the background noise).

As I cut between these two actors, the noise levels change to the point where it's annoying. How do I fix this? I've messed around with cross fades between cuts and room tone, but it's still not great. Any tips? I can't do ADR, the actors are gone.

How does Hollywood get such clean audio? Do they eq the entire mix in some way? What frequencies could I get rid of with dialogue?
 
Hollywood either; 1. records proper levels during production, and/or 2. has ADR clauses in the actors contracts.

With some creative fades and ambience you can cover a couple decibals of bg variance. After that you might be able to dirty up the cleaner track to match but that is less then ideal and too much won't work.

If there is absolutely no way to get the original actors you could ADR the entire performance with another actor. Not a great prospect but if your back is to the wall you gotta get creative. :)

Cheers
 
I've seen a few rough cuts of Hollywood movies. It's somewhat amazing, but their audio in the field doesn't sound much different than mine. In some cases, their sound is really bad (lots of air planes in LA). They do fix a lot of it with ADR, but after the sound guys worked on it in post, lots of sound that I thought would have to be replaced with ADR, was just cleaned up in post. I'm guessing they did it with EQ. Anyone out there an expert with EQ?

Great advice wabbit.
 
I'm no expert with the EQ, but here's a simple trick that I found helps out quite a bit when dealing with frequency-specific noise (eg. A-C hum, traffic, sibilance, planes, lawnmowers).

Common sense tells us that the best way to start is to set a fairly narrow Q on a parrametric EQ, attenuate that frequency range, and then sweep the frequency setting up or down until you hear the noise noticeably drop. However, the opposite approach is often quite easier: boost that EQ range, then sweep it until the noise really jumps out at you. Once you've found where the noise is sitting, you just bring the EQ level back down and adjust the Q until your dialogue track starts sounding better.

If you don't have access to a parametric EQ, you can accomplish the same thing using a fixed-band graphic EQ: raise the individual bands one by one until the noise jumps out, then drop that band to reduce the level of that particular noise.

Of course, most noises you're likely to run accross are going to be rather broad-band, making selective EQing not that effective. This method is best suited to constant noises that accupy a fairly fixed frequency range. If you find that you're getting a lot of low frequency noises (eg. planes, traffic rumble), try using a high-pass filter to roll off anything below 120 Hz. If that works, try lowering the HP filter to 80 Hz.

Beyond that, I usually rely on a combination of gating (lowering the dialogue level when noone's speaking), crossfades, and dirtying up the clean lines (as Wabbit described).

You may want to listen to the out-takes, in case there's a cleaner recording of the lines in question that you may be able to cut in to fit.
 
Also consider broad band noise reduction using Waves Restoration bundle and or Sound Soap Pro. Both have done miracles for me on the A&E Biographies I have produced where we obtained HORRIBLE sounding archival interviews and film trailers. They turned horrible, unusable to merely lousy sounding, which is actually quite a feat.

Dan
 
The "big" trick is editing, not EQ. As a rule dialog editors don't do any destructive processing like EQ on the tracks. Mostly it's finding alternate takes and syncing them in, grabbing tone and pasting it over car bys etc. In other words a LOT of work. EQ can help a bit but you cant' to that much. NR plugins and such work OK to really well on "noise" and "hums" but not at all on things like traffic and planes.
 
You must log in or register to reply here.
Back
Top