In the second of a series of articles aimed at music mixers who are learning about post-production we examine how compressors have more character, and that when mixing a song you can get away in using the same type of EQ across the board, it is unlikely that you can do the same with compressors.

This series of articles is written for the aspiring mix-to-pix mixer coming from the music mixing background (P.A. or CD). Throughout these articles, tips and tricks will be given to help you get a hold with the ins-and-outs of audio post-production workflows. The tools are roughly the same, but their use has a slightly different interpretation than in the “music world”. Since you already know most of the tools, I will skip using “baby steps”. As the series unravels you will be guided in how to modify your workflow to a surround sound session, upgrade your listening environment, what to listen for and everything in between. Very exciting indeed.

Those of you who read through my previous article EQ Is Not Just A Sweetener - Free Audio Post Production Expert Tutorial, some of you noticed that I wrote: “…an EQ is an EQ and a compressor is a compressor.” A bit simplistic, but it still holds true from the DAW’s point of view.

From the sound point of view, there are greater “personality” differences in compressors than in equalizers. You could get away in using the same type of EQ across the board, unlikely with compressors (Comp).

When you are mixing a song you do not have the same type of compressor for the voice as you would use for the bass, right?

The same applies to post-production. Usually, every Production Track has its set of EQ-Comp, then Sound Effects (SFX) get their own, Foley, Music, Voice Over (VO), etc. Usually, Ambiances (or Backgrounds) do not need a compressor, as they are well “tamed,” meaning the sound is usually consistent from beginning to end. If something has to go “wild” it’s usually dragged to the SFXs, but EQ is readily available on every track.

What A Compressor Does

We all know what a compressor does, it brings down the loud sounds and brings up softer sounds. Surprisingly, the human speaking voice has a lot of dynamic… a lot, and when you have to mix it with screeching tyres, or aeroplane whines, with blaring music you need to compress … “en masse”.

Contrary to mixing a song, the compression applied to lead vocal is usually unnoticed, and when soloed it still … holds, soloing production sound, as described earlier, will make your head spin, but it works.

What To Look For In A Compressor?

Again the question arises: “Do I need a special type of compressor?” The answer is inexpensive, you could make do with the generic compressor supplied with your DAW, but over time, you will get more sophisticated and you will be able to pinpoint the exact kind of compressors for your each of your needs.

To help, here are some obvious guidelines…

• An Opto or a Tube-like compressor would not be a good idea for Production Sound but would be great for Narration or anything with low-frequency content.

• VCA designed compressors are fast and well suited for Production Sound, Foley, SFX, and anything that needs an extra edge.

• Multi-Band compressors? Big fan, I usually put them on every stem … just in case.

As previously mentioned, 85% of your time will be spent on repairing, matching, massaging production dialogue… real soon you will appreciate the invention of automation.

Which Comes First?

Post-production sound also has its own philosophical dilemma, not unlike the chicken or the egg, a legitimate question would be: “Do I put the EQ before or after the compressor?” The answer might sound indecisive, both have their merits… and pitfalls. Personally? I prefer the EQ before the Compressor.

My reasoning is quite simple: I do not want the compressor working uselessly on frequencies that I will be discarding. It makes for better listening. And if I do need an extra EQ boost-cut, the EQ on the Dialogue subgroup can catch it.

Dialogue Premix

When you receive the dialogue edit from the picture editor (usually AAF or OMF), your first order of business, once all the tracks are assigned, the edits have been optimized and what needed to be de-noised has been de-noised, is to determine the “sound footprint.”

With a given production sound mixer, every production has a “sound footprint,” too high, too low, too bright, too dark, etc. Once you have established the “footprint” you have a good working preset to start with, you are ready for the Level-EQ pass. With faders set to unity gain, you apply that preset to the production tracks for the whole project, then go through every piece of audio and you make sure the levels and the EQ are… 95% workable. Don’t worry, you will be coming back to fine-tune the last 5%.

My secret is that I automate the “Trim In” of my compressor, making sure my compressor “gives me” a more consistent level without “choking”, and if I need more gain at the end of a sentence, I simply raise the compressor’s Trim In.

To note, I never compress with more than 6 dB of Gain Reduction, as I tell my students, “If I need more level the solution is elsewhere.” And these solutions vary from momentarily lowering the EQ of a SFX, or a Sound Design element, or an instrument in the human voice range, etc. The good part is that it happens so quickly that the mind does not recognize the deception.

Another great way to work is by combining the EQ and the Compressor in one Plugin, commonly known as a “Channel Strip”. The advantages are numerous :

• You just have to manipulate one plugin

• It’s usually less of a hog on the DSP

• Eats up one (1) less Insert point

What About Limiters?

Interestingly, the promise of digital was supposed to give us more headroom. Unfortunately, the industry just pushed everything up… way up, where -0.01 dBFS is the new “normal”. So the Film and Television industries had to come up with new standards to put back some kind of sanity in all of this artificial loudness war.

So depending on what part of the world your mix will end up, different loudness standards have been implemented. Most of them are in the same “ballpark”, yes, but just enough to be incompatible. One mix does not rule them all. We are not going into detail here, instead, I will reserve that for a future article, suffice it to say that peak, especially True Peak, is on everybody’s radar.

So yes, limiters are still being used, not necessarily in a creative way, but in a “Safety net” one. With high thresholds, just enough to grab the occasional peaks.

After reading this article are you going to go for a Channel Strip? Which one? If you have any questions, comments, insights, please do share them in the comments below.