Use Compressors to level out audio volume

I do a lot of interviews and my subjects often vary significantly in their volume. Introspectively quiet moments may be followed by revelatory exclamations. Being a one-man crew, I don't have the luxury of riding gain. I setup with a good amount of room, shooting for -12dB as a test volume, knowing most people will increase in volume once the conversation gets going.

In post production, I'm learning to use a compressor in Premier Pro to help level out those peaks and troughs without having to manually keyframe every change in volume. Regardless of your software or hardware setup, a basic understanding of how a compressor works can save a LOT of tweaking time and may salvage difficult audio tracks.

Threshold sets the level at which the signal is considered to be "too loud." Anything over the threshold level will be affected by the compressor.

Ratio determines the strength of the compression. Higher ratios will compress down further.

Attack tells the compressor how quickly to respond to a high signal or how long after the threshold is exceeded before the compression occurs. The shorter the attack time, the more quickly the compression will occur.

Release is the duration of the compression effect before returning to an uncompressed signal. Long release times may result in compression continuing after the offending signal has expired.

Gain boosts the resulting compressed signal by a set amount.

By setting a low threshold with a high ratio, usually leaving default attack and release times, and then adding back some gain, I can bring up the quiet parts of the interview while preventing the loud sections from blowing out.

Not being an expert myself, here's a great resource for getting a handle on the terms, tools, and functions of the settings in most compressors, threshold, ratio, attack, release, and sometimes knee.

MASTERINGBOX2.0 has a great explainer page on The Audio Compressor: Breaking Down the Parameters, by Tim Dunphy