[Jeff Allen]

Here’s the basics on how I was taught to clean audio before mixing.

Stage 1: Clean.
Scrub audio: Using your sound head listen and look for pops, pings and gargles in your audio. Use copy and and shift-command-v to copy and replace where ever find these pints.
Run noise cleaner as needed.

Stage 2: EQ
Use EQ filter to do the following:
Filter out any hum found in your audio (not always easy).
Filter out low end (40htz or below) and clip down your hiegh ends (around 20k).
Fill out the roundness of your audio. More often then naught your mic is going to either catch your high end, middle or your low end well, but never across the board. Use your EQ to boost up where your mic was deficient till you get a good round sound.

Stage 3: Boost audio levels and Compress
First, manually scrub through your audio and bring levels to match across the board (IE if you’re dealing with VO’s for instance, make sure they all at the same audio levels across the board).
Use a compression filter to boost the volume of your audio while keeping your peeks from db out.

Stage 4: Normalize
Use normalization filter to bring your audio down to a basic across the board range.