Audio Compression is Not the Answer for Crafting a Stellar Mix

_{Photo by Kelly Sikkema on Unsplash}

It’s popular to believe that compression in mixing is the secret to achieving exceptional results. 

Compression is a powerful tool, but it’s not magic. Too often, mixers reach for a compressor as a first resort when something sounds off. The truth is, compression alone cannot salvage a bad mix. If you’re applying it to a problematic mix, you’re likely to reinforce or amplify issues that should have been addressed earlier in the mixing process.

So before you start twisting knobs and putting parallel compression on everything, let’s talk about what needs to happen first.  Because when compression is applied to a solid, well-balanced mix it enhances the mix. But when it’s used incorrectly, it can produce undesirable results.

Understanding Compression.

At its core, a compressor regulates the dynamic range of a signal, narrowing the gap between the loudest and quietest sounds. This function is vital for preventing clipping, managing transients, and maintaining a cohesive blend within the mix. 

Compression can be categorized into two broad types: Corrective and Creative.

Corrective compression is used to smooth out erratic performances.  For example, taming the spirited playing of a bass player or reigning in the dynamic range of a vocalist who vacillates between a whisper and a scream. 

On the other hand, creative compression involves using it as a tool to create loudness or to impart the distinct characteristics of the particular compressor into a track, contributing to the overall coloration of the mix. 

A little compression applied to the overall mix can increase headroom when mixing live sound, and it can help to pull a mix together.  However, misused or overused compression can be detrimental to a mix. Often, an inexperienced engineer will try to use a compressor to remedy problems in a mix that should be solved by other means.

The Myth: Compression will fix everything.

If your vocal is getting buried, if your drums are dull and lifeless, if your guitars are thin and shrill, compression is not the first solution. You could end up sucking the life out of the track, adding noise, or creating what’s called pumping, an unnatural sound created from incorrect attack and release times.

The first step is getting your sounds right, at the source.

A great mix starts long before your mixer or DAW. The performance, the instruments, mic choice and placement matter more than anything you do later.

Is the drum kit well-tuned?  Are the drum heads in good shape?  If the heads are worn out, replace them and tune them properly.  This will facilitate a nice punchy sound.

Did you record a hight-quality vocal in a good acoustic space?  If it’s a live performance, is the singer using the right microphone, and do they have good technique?

Does the guitarist need some help dialing in their tone?  Is the signal noisy from bad cables?

Fix any problems at the source so that you have a good, strong signal going to your mixer or DAW.

If the raw sounds aren’t solid, compression will only highlight inconsistencies or unpleasant tone. Don’t try to “fix it in the mix”—fix it in the performance or recording stage if possible.

Get the gain staging right.

Make sure you have optimal gain going into your DAW or mixer. This sets you up for all the signal processing that follows to function properly.

Proper gain staging gives compressors room to breathe and respond musically.

Build a solid mix.

Spend some time creating a well-balanced mix. If you have good sounds and solid signal levels, the mix can come together fairly easily.

•  Can you hear every instrument and vocal?
•  Is there anything dominating the mix
•  Is anything getting lost?
•  Do you hear definition between the instruments?
•  Are your vocals sitting comfortably in the mix without effects?

A combination of panning, EQ adjustments, and level balancing will help each element find its place within the stereo image. 

Panning for placement.

Panning opens up space in the stereo image and allows elements in the mix to coexist without stepping on each other. It shouldn’t be used randomly, use it intentionally based on the arrangement, instrumentation, and perspective of the listener.  For more on panning, CLICK HERE

Use EQ to solve problems.

A common mistake is compressing a muddy guitar or boomy vocal before EQ’ing. You’re just compressing the mud, not the music.

EQ is a fantastic tool for solving problems in a mix.

•  Use EQ to remove unwanted frequencies: low-end rumble, boxiness, harshness.
•  Carve out space between instruments (e.g., cut 200–400 Hz in guitars to make room for snare).
•  Add attack to the kick drum and toms for punch (e.g., boost 3kHz and 6kHz)
•  Clean up muddiness from vocals 

I teach EQ in depth in my course LISTEN!.

Engage the High-Pass and Low-Pass Filters.

The high and low-pass filters are excellent for getting rid of buildup in the sub and high frequencies where it’s not needed.

These filters can clean up a lot of mud and ambient noise, and free up space in the frequency range for instruments that belong there.

Removing unwanted information using EQ and filters before adding compression will allow the compressor to function correctly and prevent it from reacting to problem frequencies unrelated to the musical content.

Now is the time to apply corrective compression.

If dynamic signals can’t be managed by manually riding the fader, judicious use of compression can smooth things out and keep things from inappropriately jumping out in the mix. 

For example:

•  The bass player alternates between percussive slapping and plucking.
•  A keyboard player whose sounds vary dramatically in volume. (Check out this blog).
•  A singer who shifts quickly between soft passages and belting it out.

At this point, your mix should begin to take shape. If, however,  things are not sounding as you’d like, it is best to revisit and rectify any underlying issues before applying tools such as creative compression and effects.

Creative compression.

When you have a well-balanced mix in place, compression can be used as a shaping tool. 

•  On drums, to pull the kit together and add energy to an already tight groove.
•  On acoustic guitar, to add sustain.
•  On a vocal, for coloration.
•  On bass, to keep the low-end consistent.
•  On the mix bus, to gently “glue” a well-balanced mix together.

However, use it sparingly, especially if you are not well-versed in its operation.

An inexperienced hand can suck the life out of a mix by overusing compression or improperly adjusting settings like threshold, attack, and release. The result may be unwanted artifacts that compromise the integrity and natural feel of the music.

It’s good practice to check your compression.  Bypass the compressor and ask does it sound better with compression or just different?  If it’s not making a noticeable improvement to your mix, you may not need it.

Where to put it, Pre or Post? 

Compression can be applied pre-or post-EQ, depending on the desired result. 

When inserting a compressor post-EQ, any boosting you do in the EQ has the possibility of driving the signal into compression, depending on how the threshold is set.  The loudest frequencies of the signal trigger the compression. This is a good option for softening annoying or unwanted frequencies from a source, for example removing unwanted sibilance from a vocal. 

Inserting a compressor pre-EQ allows you to make needed adjustments to the EQ without affecting the compressor.  For example, if you are shaping your drum sounds with EQ to add more punch, and would like to add some compression for dynamic control, you would want to put the compressor before EQ in the signal chain.

In conclusion.

Compression can be a powerful tool in the mixing process when it is used correctly.  But it is not a magic bullet that will fix the problems of a poorly crafted mix.  It should come after you have a solid mix in place.  

Mastering the fundamentals of great sounds, optimal input signal, EQ, and balance paves the way for the strategic application of compression, resulting in mixes that are not only technically sound but also artistically compelling. 

The real secret to great compression is knowing when to use it and when not to.

By: Michelle Sabolchick