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PODCASTING

Blue’s Podcasting Basics: Understanding Compressors

One of the hallmarks of a professional podcast is an instantly recognizable high-quality vocal sound.


Welcome to Blue’s Podcasting Basics. A series of articles that give you helpful tips on how to edit and mix your podcasts to sound their absolute best.

One of the hallmarks of a professional podcast is an instantly recognizable high-quality vocal sound. That beautifully rich tone that lets you zone in on the story and forget about everything else. When you set out to create your own podcast, that’s what you want to shoot for. And though what you hear in other recordings may seem elusive—you, too, can have a vocal tone that stands out. 

The answer? Compression.

Well, it’s one of the answers anyway. And I’m not talking about tiny shorts to wear while prepping for the Tour De France. I’m talking about basic signal processing to give your vocal a gorgeous and consistent sound. This article walks you through the basic settings you’ll find on compressors to help you understand this powerful tool.

“Dynamic range” is the range of loudness from your quietest to loudest moments in a given track

LEVEL YOUR VOCAL PLAYING FIELD

When you record a podcast, there are moments when you’re quiet, and other times when you’re more animated and loud. That’s natural, and part of being a dynamic and interesting speaker. The problem is, this dynamic range of sound—from when you’re quiet to when you’re loud—doesn’t make for great radio. 

Two common types of meters that display “gain reduction” on compressors, outlined in blue. This shows how much volume is reduced once the threshold is crossed.

A compressor reduces the louder parts of your speech while raising the overall volume of your track. The quieter moments get louder, while the louder moments stay at a controlled volume. So whether you’re speaking normally or getting pumped up, the listener gets to hear each word clearly along with all of the emotion and tone in your voice—at one comfortable volume.

But compressors don’t just give you a more consistent dynamic range. They can also give your vocal a distinct and rich tonality that you otherwise lose by just speaking into a microphone.

Compressors generally come free with the recording software you use. And while I hate to make blanket statements, I’d say every podcaster should absolutely be using compression on their vocal. The pros are. (I promise.)

COMPRESSOR’S ANATOMY

Compressors are powerful tools that can be used for many, many applications. But for the purposes of podcasting, they’re pretty simple. Let’s check out the features of almost any compressor you’ll come across as they relate to compressing a vocal.

Threshold controls on three different compressors outlined in blue.

Threshold

The threshold is the volume at which the compressor starts reducing the volume, or gain, of your track. You’re basically saying, “If I get louder than THIS, start compressing.”

Ratio controls on different compressors outlined in blue.

Ratio

The ratio determines just how much compression happens once you cross the threshold. With the ratio you’re saying, “Once I’m this loud (threshold), reduce the volume by THIS amount.” Most digital compressors are automatically set to the industry standard of 3:1. You can increase the ratio as much as your software will let you—5:1 is another popular setting. The higher the ratio, the more dramatic the decrease in volume once you’ve crossed the threshold.

The reason that most compressors are set to 3:1 is because it sounds pretty natural to the ear. The compression can be more or less invisible to the listener. And when it comes to podcasting, that’s what you want.

Attack and Release sliders on Audacity’s Compressor plug-in, outlined in blue.

Attack & Release

Attack and release are basically how quickly the compressor reacts. They’re set in milliseconds. So for Attack, you’re saying, “Within THIS amount of time of crossing the threshold, compress the audio…” The same is true for Release, but in the opposite direction. Release dictates how quickly the compressor stops compressing the audio after it falls below the threshold.

 

 

 

MAKE UP dial on Logic’s compressor outlined in blue. This is sometimes labeled as “Output” or “Gain” or any combination of the above, like “Makeup Gain.”

Gain

Compressing your vocal reduces the loudness of your entire track. So compressors have a gain or “makeup gain” setting to help you raise the loudness of your track after the gain reduction of the compression.

Knee dial on Logic’s compressor set as a “hard” knee (left) and also as a “soft” knee (right), outlined in blue.

Knee

Some compressors have a “knee” setting. The knee determines the rate at which the audio goes from uncompressed to compressed. A “hard knee” means that the sound goes from uncompressed to compressed very quickly. In many cases this can be pretty audible. A “soft knee” on the other hand is more common. A soft knee gradually compresses the audio across the threshold.

From left to right: JJP all-in-one vocal plug-in with a single “comp” dial and other controls, Hindenburg Journalist’s one-knob compressor, and Garage Band’s effects unit with a one-knob compressor. In these instances, increase the compressor until it sounds pleasant to your ears, and let the plug-in do the rest!

I don’t see any of this stuff…

Some very basic compressors—and some specialty all-in-one plug-ins—may have a compressor section that has a single knob. Or it may have controls like “air” or “sparkle.” In these instances, the application itself has specific settings that automatically control the variables listed above. When you turn the knob up, you basically control how much the compressor is affecting your vocal.

We’ll talk about this later, but when you come across this type of compressor, the best thing to do is to experiment, use moderation, and most importantly—let your ears be your guide.