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When and how to use compression in music production.

Updated: Jan 13, 2023

Introduction to Compression in Music Production



Compression is a fundamental technique in music production that is used to even out the levels of audio signals and control dynamics. This article will dive into compression, when and why it is used in music production, and some of the best plugins available for achieving it.


Table Of Contents


What is Compression


Compression is a process that reduces the dynamic range of an audio signal, or the difference between the loudest and quietest parts. It does this by boosting the softer parts and attenuating the louder parts, resulting in a more balanced and consistent level.

Compression is achieved through a compressor, which is a device or software that applies the compression effect. A compressor has several parameters that can be adjusted to shape the effect, such as the threshold, ratio, attack, release, and makeup gain.


Below we'll discover what each of these parameters does.





Threshold


Before a compressor starts compressing, the incoming signal must exceed its threshold. For instance, if we set the threshold of a compressor to -18 dB, anything below -18 dB will not cause the compressor to activate. Any sound that is louder than -18 dB will then signal the compressor to begin reducing gain.


When to activate the compressor is determined by the threshold, and the amount of gain reduction is determined by the ratio.


In general, compression is used to isolate the loudest peaks in our dynamic content. Therefore, the ideal place to start is by selecting a threshold that decreases and captures such peaks in order to make our track level more constant. Be careful while setting the threshold since if it is too high, the compressor won't operate at all.


Ratio


In general, ratio choices vary from 2:1 to 10:1. Your compressor becomes a limiter at a ratio of 10:1, but we won't get into that just yet. The ratio setting on a compressor is just that; it denotes how the input signal and output signal are related.


An input signal of 2 dB will output at 1 dB at a ratio of 2:1. A 10 dB input signal will result in a 5 dB output, and so on. Your input signal is being diminished by a factor of two at a 2:1 ratio.


The ratio establishes how much a sound is compressed, or how much its loudness is lowered.  A compressor doesn't operate constantly, though. Gain reduction is not implemented until the input signal exceeds a threshold that has been set by the user.


Attack


So far, we have discovered that the ratio controls the amount by which our input signal is lowered after crossing the threshold. What occurs when the signal does go above the threshold, though? Does gain reduction start working right away? No, not always.


The attack setting determines how long the compressor waits after the input signal crosses the threshold before performing gain reduction. If the attack time is set to 5 ms, gain reduction won't take effect for 5 ms after the input signal crosses our -18 dB threshold.


Depending on the sound and a number of other parameters, you will change the attack time from instrument to instrument and even from song to song. Slower attack times—between 20 and 40 ms—work best the majority of the time. A slow attack causes the full note to be compressed rather than just the initial transient once it reaches the threshold. Fast attacks work well for crushing fast transients, such as those produced by a guitar being played quickly.


Release


Another speed option that controls how fast the compressor shuts off when the signal falls below the threshold is called release. Once more, this is a crucial parameter that eventually affects the sound of the compression.


The audio might sound weird if the release is made too quickly. The compressor never switches off if it moves too slowly. It's usually suggested to fiddle with the release time until the sound feels good in the pocket. A 60 ms beginning point is a decent place to start. The general rhythmic vibe and pace of the song itself will determine where you go from there.


Makeup Gain


The level of our track as a whole will be lower than it was before we applied compression since compressors actively reduce volume as indicated by the ratio or threshold. The "makeup gain" or "output" setting on the compressor is a simple way to restore the lost gain. 


The makeup gain should be increased until the level coming out equals the level going in, as a general rule of thumb at least. However, you may increase the makeup gain, even more, to make a track louder overall.




When to Use Compression


Compression is commonly used in many stages of music production, including mixing and mastering.


Mixing


In the mixing stage, compression is used to even out the levels of individual tracks and make them sit well in the mix. It is also used to add punch and clarity to drums, tighten up basslines, and add sustain to guitars.


Here are some tips for using compression in the mixing stage:

  • Start with a high threshold and a low ratio, and gradually increase the ratio until you achieve the desired amount of gain reduction. This will help you avoid over-compressing the signal.

  • Experiment with different attack and release times to find the settings that work best for the source material. A fast attack and release may work well for drums, while a slower attack and release may work better for vocals.

  • Use makeup gain to bring the level of the compressed signal back up to where it was before the compression. This will help you avoid losing the overall level in the mix.

  • Use compression sparingly on individual tracks to avoid a cluttered and overly-compressed mix. Instead, focus on using compression on key elements, such as the drums and vocals, to add punch and clarity.

  • Use parallel compression to add punch and presence to a track while still retaining its dynamic range. Simply send the track to a bus, apply compression to the bus, and blend the compressed and uncompressed signals to taste.


Mastering


In the mastering stage, compression is used to bring all the elements of a mix together and create a cohesive and polished final product. It is also used to achieve a certain loudness level or dynamic range for commercial release.


Here are some tips for using compression in the mastering stage:

  • Use a compressor with a transparent and natural-sounding algorithm to avoid introducing coloration to the mix.

  • Try adjusting the attack and release times to see how it affects the source material. A slower attack and release may be suitable for mastering because it allows the initial transient of the sound to remain present.

  • Pay attention to the interplay between the compressor's parameters and the characteristics of the audio signal. For example, a low threshold and high ratio may work well for a track with a lot of dynamic range, while a high threshold and low ratio may be more appropriate for a track with a less dynamic range.

  • Use a multiband compressor to target specific frequency ranges with different compression settings. This can be useful for taming frequencies that stick out too much or adding punch to certain instruments.

  • Be mindful of the loudness level of the final mastered track. Too much compression can result in an overly-loud and distorted sound, so use it sparingly and with a clear purpose in mind.





Why Use Compression in Music Production


Compression is an essential tool in music production because it allows you to shape and control the dynamic range of an audio signal. By reducing the difference between the loud and quiet parts, compression can make a mix sound more cohesive and balanced.

Compression can also add punch and sustain to certain instruments, making them stand out in the mix. It can also be used to fix issues such as uneven levels or masking between tracks.


Types of Compression


Several types of compression are commonly used in music production, each with its characteristics and uses.


Hard Compression


Hard compression is a type of compression that has a high ratio and a low threshold, resulting in a significant reduction of the dynamic range. It is often used to achieve a pumped or squashed sound, such as on drums or basslines.


Soft Compression


Soft compression is a type of compression that has a low ratio and a high threshold, resulting in a subtle reduction of the dynamic range. It is often used to add warmth and character to a signal without altering its dynamics too much.


Parallel Compression


Parallel compression, also known as New York compression or up-front compression, is a technique in which the compressed and uncompressed signals are mixed together. This results in a punchy and present sound while still retaining the dynamic range of the original signal. It is often used on drums and vocals.


Top 5 Compressors available


Now that we've covered the basics of compression and its uses in music production, let's take a look at some of the best plugins available for achieving it.


FabFilter Pro-C 2


FabFilter Pro-C 2 is a high-quality compressor plugin that is suitable for a wide range of applications. It features an intuitive interface, flexible routing options, and a range of compressor models to choose from.


It's a fantastic stereo compressor with all the tricks you could ever need.


It may operate in any desired manner thanks to its various compression types and choices, including side-chaining with an optional EQ filter and mid/side compression. Pro-C 2 can handle both mixing and mastering tasks with ease.


Grab it here - 169$


UAD 1176SE


UAD 1176SE is a plugin emulation of the classic 1176 hardware compressor, which is known for its fast attack and release times and distinctive sound. It is suitable for adding punch and presence to drums and vocals.


M.T. "Bill" Putnam, the company's founder, created the first Universal Audio 1176, which was a significant advance in limiter and compression technology.

The 1176 is a simple-to-use "desert island" compressor that introduced solid-state circuitry and ultra-fast 20-microsecond FET gain reduction. It has added character and punch to some of the best recordings in history.


Grab it here - 199$


Waves SSL G-Master Buss Compressor


Waves SSL G-Master Buss Compressor is a plugin emulation of the iconic SSL 4000 G console's bus compressor, which is known for its smooth and transparent sound. It is suitable for adding glue and cohesion to a mix.


The Waves SSL G-Master Buss Compressor, which is based on the famous master bus compressor of the SSL 4000 G console, reproduces the distinctive sound of the original's IC input and twin VCA gain-reduction amplifier design.


The SL 4000 G master bus compressor, prized by renowned engineers for its ability to "glue together" songs, is perfect for controlling piano dynamics or giving drums and percussion more punch.


Grab it here - 39$


iZotope Ozone 10 Dynamic EQ


iZotope Ozone 10 Dynamic EQ is a hybrid plugin that combines the functions of an equalizer and a compressor. It allows you to shape the frequency spectrum of a signal with dynamic control, making it suitable for problem-solving and creative applications.


Features of a dynamic EQ:


  • High/low shelf, Proportional Q, Band Shelf, and Peak Bell are among the five filter shapes available.

  • Switch between analog and digital modes to analyze data in minimum or linear phase over six distinct bands.

  • With the Mid/Side and Left/Right processing modes, you can access targeted dynamic equalization.

  • Utilize Auto-Scale mode to intelligently alter Attack/Release periods automatically over the frequency range.

  • Dynamic nodes display your changes' direction, making it obvious if you're expanding or contracting.

Grab it here - From 249$ along with the Ozone 10 Full Suite.


Softube FET Compressor


Softube FET Compressor is a plugin emulation of the classic FET hardware compressor, which is known for its fast and punchy sound. It is suitable for adding punch and presence to drums and vocals.


The FET Compressor allows for a deeper gain reduction than you would typically achieve with any other compressor.


The FET Compressor exhibits no sign of the pinched sound that other compressors generate when pushed hard, even at severe levels.


Lead vocal recordings that need to be kept in the listener's face will benefit most from this as, the voice is given a great grit by the distortion, which is excellent for rock and EDM mixes but not exclusively so.


Grab it here - 199$


Summary


Compression is a technique used in music production to even out the levels of audio signals and control dynamics. It is achieved through a compressor, which has several adjustable parameters such as threshold, ratio, attack, release, and makeup gain.


Compression is used in the mixing and mastering stages of music production to balance levels, add punch and clarity to drums, tighten up basslines, add sustain to guitars, bring all the elements of a mix together, and achieve a certain loudness level.


There are several types of compression, including hard, soft, and parallel compression, each with its own characteristics and uses. Using compression effectively requires finding the right balance between the compressor's parameters and the audio signal.


Some of the best compression plugins include FabFilter Pro-C 2, UAD 1176SE, Waves SSL G-Master Buss Compressor, iZotope Ozone 9 Dynamic EQ, and Softube FET Compressor.



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