Removing Audio Problems Part 1: The Basics | DiY Filmmaking

Removing Audio Problems Part 1: The Basics

We’ve all been there before. You have a great shoot, and you get back to your editing system and discover that there was a problem with audio that you didn’t notice when you were filming. It sucks, because what are you going to do? Reshoot the whole thing? Of course not, and that means working with what you have.

It’s a common and difficult problem, so we are going to do a series of articles on how to deal with different types of audio problems and with what programs. But before we get fancy, we have do get down to some basics.

Enhance!

I like to sit down and enjoy an episode of a procedural crime drama like “CSI: Miami” or “CSI: Someplace” every once in a while, but I have to laugh when they deal with anything audio or visual. The common use of technology that doesn’t exist is the “enhance!” feature where a blurry security camera is somehow enhanced to allow us to read a license plate off the back of a car. It’s fun, but it’s stupid, because you can’t do that in real life. It’s just technically impossible to create data where there is none.

The same goes for their treatment of audio. Usually, a garbled piece of audio is brought into their A/V department and it comes out pristine, so they can get the one piece of evidence they need. Usually this can be done with Horatio standing over the technician’s shoulder.

Like the video part, the audio treatment is completely fabricated, but it plays into a common misconception about audio in general: that you can “remove” something from it or “enhance” a part of it easily.

Can you do those things? Yes, but it is much more difficult than TV has led everyone to believe.

Audio Soup

Think of your audio track like a big pot of soup. There are spices, carrots, peas, chicken, and a bunch of other stuff all mixed together. It’s delicious, but has a flavor problem. It would be much better if we took the carrots out. Okay, no big deal. You can see the carrots – they’re orange. You get a spoon and start picking them out.

So you start taking the carrots out, and you soon find out it’s not as easy as you thought. You keep removing parts of the soup you didn’t intend to, like some broth. But after a while, you manage to get them all out. You took some of the soup with it, but that’s going to be okay.

Now, for your next assignment, you have to take the oregano out.

What is “Fixable”?

Audio is like the soup – all mixed together and messy. You can’t just “remove” something easily and without consequences, but if you know exactly what you need to get, you can take it out with some work if you don’t mind losing a little bit of other audio in the process.

What makes something a carrot? It has to be something that is uniform throughout the audio, like a hum or a hiss. Something that can be easily identified and is always there. The carrots are still in the soup, they are just identifiable.

Obviously, it’s impossible to remove the oregano because it’s too much a part of the soup. If you really wanted to take it out, you’d damage the soup heavily, and you’d have a hard time figuring out what is oregano and what isn’t. There would probably be some left in there when you’re done too.

The oregano elements in audio are things like a cough or a car in the distance during dialogue. It’s too embedded in the sound to be completely removed.

Next: Removing the Carrots

Soon, we’ll be posting round 2 of talkin’ about audio, with a list of tools to remove carrot-like audio problems, and some methods. Stay tuned!

via Removing Audio Problems Part 1: The Basics | DiY Filmmaking.

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