Types of Audio Compressors and When are They Used in Mixing


Are you confused hearing about VCA, FET, OpticaL, and Variable compression? And have zero ideas when you use or how to use them? Well, you are not the only person in the world who doesn’t know about the types of audio compressors.

There are many young and aspiring music producers who are new to music production and who fail to understand the difference or have any knowledge about them.

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In this blog, we broke down the features and characteristics of each compressor and covered everything you need to learn about the types of audio compressors.

When started, the compressor can be a little tricky and messy that can also spin your head around. Now you must think that the process must be difficult, but no… the principle is pretty simple. you are just needed to play with the louder and quiet part of your track.

When you put the louder part down, and raise the lower part, you get a perfectly balanced sounding audio. With these simple steps, you get a compressed audio file.

Learning about each type of audio compressor, you get the knowledge of how and when to use them so that you get your overall quality of audio perfect and not disturbing to the ears. So let’s learn about what is Audio Compressors in detail.

what is audio compressor?

Generally, the work of the audio compressor is to bring the higher and lower dynamic range of the sound to a level by making the louder part quieter and quieter part louder.

When we apply compression, it distorts the signal. Through processing, this changes the primary sound of the signal. The compressor identifies the incoming signals and based on that, it emphasizes specific harmonics.

Now our job here comes to create a best-sounding performance as much as we can by using our dynamics. And in the end, we get the narrow dynamic range between the highest and the lowest parts, where the dB difference becomes quite narrow.

when to use the Audio compressor?

The first reason is, when you have a track where the difference between the level of your instruments and vocal is a lot, you get mixed-sounding audio. To clear that and to get a balanced sounding audio file, compression is used.

Either you can do this manually, or use the compressors that are already available in the market. If said, most people prefer doing manually even after applying the compressors. This helps out bringing the quality sound of the audio and then the mixture becomes quite a lot easier.

You need to keep in mind, that using a compressor for reducing the dynamic range is the easiest way to get things done. Also, you can use fader-riding and automation to make your work even easier and hassle-free.

Another reason is maybe if you think without the compressor, your track is sounding just perfect, USE IT!!!

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If you want your lead vocal to stand out and create a huge and unique impact, compression is the way you can do so. It brings out the sound quality more pleasant and interesting while listening.


1. VCA compressor

Types of Audio Compressors VCA Compressor

The first on the list comes is VCA Compressor. The full form of VCA is Voltage Controlled Amplifier. When we talk about the use of these types of audio compressors, a control signal is used to determine if the gain reduction to the signal is applied or not.

what is vca compression?

A ‘Voltage Controlled Amplifier’ is the best choice for keeping the check-in any loud spikes in volume on your track. Because this compressor has the tendency to offer the most aggressive gain reduction, it’s a good option for the same.

To reduce the volume, the VCA compressor uses an attenuator. So if we talk technically, it can’t be called an amplifier.

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how does vca compressor work?

The working of the VCA compressor can be explained as an amplifier that alters its gain in proportion to a controlled voltage or modulator signal. VCA is used to either control or amplifies the amplitude of the input signal.

Basically, in VCA, three signals are involved, They are as followed:

  • MODULATOR: In a VCA compressor, this is a control input and is unipolar. By unipolar, it means, it has only positive amplitude. With the help of this input, the audio signal or say audio carrier can be altered.
  • CARRIER: This is an input AC audio signal, and normally, it is bipolar in character. Bipolar means, having both – negative as well as positive amplitudes.This is the signal which gets altered by the VCA.
  • OUTPUT: The modulator here is positive and an instantanious product of the carrier.

So basically, if the control voltage or modulator is stronger, more carrier signals will be passed through the output.

VCA Types of Audio Compressors

what is vca compressor good for?

If you want to bring down your intense peaks, VCA is the one that is going to suit your workflow. And this result you get is due to the snappy response of this compressor.

But when you compare it to the Variable-MU, or Optical, averaging out the level of a song won’t be suited according to your taste.

best vca compression plugins

To get the best results from the VCA compressor, you are required to find the best plugins that provide this compressor. Although the functions of most of the plugins are pretty similar, if we go into detail, every bit matters.

To glue their mixes, every music producer or engineer relies on VCA compressors since the 80s. So let’s get to know about them.

1. cytomic – the glue

You get a wide range of applications here in the Glue that produces sound extremely clean and clear. Cytomic – The Glue is inspired by the SSL hardware.

It doesn’t matter if you are compressing any of your just single track, entire mixes, or the busses, you are going to get enough versatility from this plugin. This compressor plugin is used in the industry and is gonna give you the same tried and true bus compression effect.

2. Brainworks vertigo vsc-2

Born from one of the original VCA Compressors, Vertigo VSC-2 is totally dependable and faithful to have in your software as an audio compressor plugin.

Every channel has two voltage-controlled amplifiers. In 1979, VSC-2 was a staple of bus compression. If you needed to use a compressor on your bus, this was a must plugin back then.

When you look even today, there’s nothing changed. You are going to see the same condition for this VCA compression plugin.

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2. fet compression

Types of Audio Compressors FET Compressors

Going down to the list of the types of audio compressors, here we come to our next one and that is the FET compressor. The full form of FET in the FET compressor is Field Effect Transistor. As the name suggests itself, for the gain reduction, FET compressors are reliable on transistors.

What is fet compression?

Well, I already gave you the full form of the FET compressor. but in the process, the large tubes got replaced with the smaller transistors. That’s why they are known as Field-effect Transistors.

The nature of this compressor is aggressive and has a unique colored tone that is loved by most mixing engineers.


In the market, if you are finding any compressor that is an all-rounder and you want it to do almost every work other compressors do, then this might be the option for you. We all know how much a compressor is capable when given a particular field to work in. Sousing an all-rounder might not be the best option here.

To make it clear here’s the graphic representation:

VCA compressor Types of Audio Compressors

FET has the fastest attack and releases time when compared to the other three types of compressors. Not just that, even the slowest time on FET compressors is faster than that on Variable-MU compressors.

Every compressor work by compressing the audio signals effectively by reducing the gain. to a control signal. Input audio signal derives this control signal(sidechain) or through an external audio signal.

When we talk about FET compressors, a field-effect transistor is surrounded by the gain reduction circuit.

What is FET Compression Good For?

FET compressors are best for vocals, guitars, kick, drum, drum, snare, and more of you can think of. As I said, they produce the fastest attack which causes lovely colors to the signals, now because of that, you might not get a clean VCA compressor on a mixed bus, but when for individually, the results you get are stellar.

You get a really punchy tone and great sound on any of the instruments or vocals for the fact. So it shouldn’t be of a surprise when you see a FET compressor in any big recording studio.

If we talk about the most famous FET compressor, there comes the name 1176 Limiting Amplifier. The compressor was introduced in the market in the late 1960s.

This particular version is said to be the most iconic featured FET compressor that has the capabilities to give you the full energetic sound. When you pull all the four ratio buttons simultaneously, you get an aggressive and very musical result.

Along with the time, 1176 has revised itself around 13 times, and each time, it brings a uniqueness that is loved by everyone.

best FET compression plugins

Below you’ll get two of the most recommended FET Compressor plugins that are best in the field.

softube fet compressor

Softube FET compressor is one of the first excellent plugins based on the legendary Urie 1176 FET compressor.

You don’t need to worry about the support of any operating system. This compressor is supported on Mac OS and Windows OS. You get it in AAX, AU, and VST formats.

In order to deliver the better performance quality of 1176, the model of an analog hardware unit is used on every stage of Softube’s FET compressor. This model provides excellent analog distortion at the input as well as output. Also, there is the presence of our beloved ‘All Buttons In’ mode.

Arturia Comp FET-76

Now, this plugin is the best example for emulation with the D/E model of Urei 1176. The Arturia Comp FET-76 is also made for all the operating systems such as Windows OS and Mac OS.

As we know by now, In the 1960s, 1176 D/E was a highly celebrated compressor. And Arturia Comp FET-76 plugin was made by recreating the same compressor. With the help of simple controls provided on the plugin, this plugin can capture the aggressive vintage tone from 1176.

Due to the extreme power that Arturia Comp FET-76 has due to TAE modeling technology, getting the benefit of the legendary fast attack and tone-shaping becomes very convenient.

3. optical compression

We call it Optical Compressor or Opto Compressor, one and the same, are the ones that rely on a light-dependent resistor and a light source that helps in dictating the way through which the compression can be applied.

what is optical compression?

Types of Audio Compressors Variable Mu

As you know, Optical compression is also called Opto-Compressor, and it uses a light source in order to control the gain reduction accordingly.

The speed of an Opto-Compressor is quite less when compared to the speed of light. So it depends on the level of signals, how much the light bulb will glow. And lighter the bulb glows, the higher the signal this compressor receives.

Due to this technique, an Opto Compressor works off as much it receives the signal.

How does optical compressor work?

The input signals of the optical compressor irradiate a light source. It works like when more power flows through it, you get the brighter shine of the light.

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And when the light source irradiates, a message is sent to the compressor to apply the compression. And when the light goes dim, there you see a reduction in the amount of compression applied.

The sidechain controls the optical photocell arrangement effectively and it acts as a variable resistor. That resistor controls the limit of the compressor.

Below I’m presenting the visual demographic of how does an optical compressor works. As I already told you that in the gain reduction circuit, the light source and LDR would be the important variable-resistance element of the gain reduction.

There’s a thing that you need to note here is that until you use any external sidechain, audio input is going to act as both – a compressed audio signal as well as the sidechain signal through which, the compression is controlled.

What is Optical Compression Good For?

If you are trying to get a great result trying to control short and sharp transients with the help of the optical compressor, maybe you can’t get the results as same as you get with the VCA. But, with its help, you will be able to create a smooth compression at an away much higher ratio when compared with others.

When you get the smoother compression, the reaction produces a much more pleasing sound. This is because, with the compressor, the signals don’t get squashed with each other dramatically.

If you are familiar with the DAW, you must have definitely come across the words – ‘Peak’ and ‘RMS’ options in your DAW. And if so, then you don’t need to think twice about anything. Opto-Compressor is the best one for an RMS signal.

The work of the RMS is basically to average out the signal coming through and the peak, will whereas display your peaks. This way is the best way to visualize how an Opto Compressor works.

Using an Opto-Compressor is really going to add life to your sound. So enjoy using it and keep adding colors to your sound that is gonna loved by everyone.

Best Optical Compression plugins

Following are the best Opto-compression Plugins that I recommend and are best in the field. You can use them seamlessly and get your song to sound more clear and colorful.

1. cakewalk ca-2a

You must have heard the legendary name of Teletronix LA-2A, now this Cakewalk CA-2A is modeled after the same compressor. It is a T-Type leveling amplifier.

You can install this plugin CA-2A on any of the operating systems. It is compatible with Windows OS, as well as Mac OS. The format in which this plugin comes is AAX, AU, Pro channel, and ProChannel.

The silky and smooth sound you get in a legendary Teletronix LA-2A, Opto-Compression also is modeled as the vision from the same compressor and offers great quality as the original one. Whatever you take, from optoelectric gain reduction to the 4 vacuum tubes, this plugin is going to give you the spot-on effect.

2. universal audio teletronix LA-2a

If you talk about Universal Audio Teletronix LA-2A, LA-2A Silver, Original LA-2A, they are the variations in character across the multiple versions of the great plugin Teletronix or Universal Audio LA-2A.

Again it’s compatible with both – Windows as well as Mac OS and comes in the AAX, AU, and VST formats.

When you purchase the bundle, you get three different types of versions of the great Teletronic Optical Compressor. They are as follows:

  • LA-2A Grey: This version was manufactured by Jim Lawrence. The constant time on this version is average that provides excellent medium-speed compression.
  • LA-2A Silver: Bill Putnam is the manufacturer of this version who also is the founder of the Universal Audio. Silver version has comparitively faster time constant than others when we talk about an Opto-Compressor. Also it’s suiatable for a variety of program materials.
  • Original LA-2: The original model is said to be rare one which was manufactured in the early 1960s. This version offeres the slowest response and unique style that’s mellow of the compression.

You need to choose the best option for yourself and enjoy making some good-sounding music or vocals.

4. Variable mu compression

Next on the list of types of audio compressors comes Variable MU compression. This is one of the oldest compressors. Being the oldest, it is the only one that gives rare quality and is quite a difficult finding on others.

As a mixing engineer, you should know about every compressor, that’s why read further.

What is Variable mu compfression?

As I said, Variable MU, or also said as Tube compressor is one of the oldest types of audio compressors, which means you are going to get an original and rare type of sound quality here.

It is an analog compressor surrounded by a vacuum tube. The current sent to the tube’s grid gets decreased when the input signal increases. This results in the reduction of the overall level of the compressor.

Below in this article, we’ll learn how does a variable compressor works, and which are plugins that are best for this compressor.

How does variable mu compression work?

Tubes and Transformers are used to control the gain reduction, making the compressions act slow. In simple ways, you can think that as much the signal will be louder, the unit will add that much compression.

In order to control the gain reduction, these types of audio compressors are dependent on the tubes themselves. This results in a smooth process without any hustles.

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You should know that there are other types of audio compressors that utilize the same function of the tube as well, but the thing that makes this Variable MU compressor different from them is that the tube is used as the gain reduction component specifically.

If you look into the Variable MU or Delta -MU, you’ll notice that the tubes could have a place elsewhere, and of course, that could be done in order to offer additional gain.

The Variable MU compressor is also called Delta MU because the term delta comes from the Greek word – Delta. Now, Delta, in mathematics, is referred to as a change in quantity, and MU in electronics is referred to as gain.

So, when we put those two words together by their meaning, the result comes as the “Changing Gain” or “Variable Gain”. That’s why it is known as “Variable MU Compression”.

what is variable mu compression good for?

As this compressor has the less aggressive character of a MU, the most suitable place for this is when you need to equal out your sources and don’t want your louder transient to get tamed. (Just for this case, VCA could be more suitable).

These types of audio compressors work as a partner that can add extra color to your mixing. Not only this, with the help of it, you can also level out your audios or instrument’s that sound thinner.

Variable MU compressor adds some amount of warmth that suits your instruments like drums overheads or guitars.

You get the benefit of the slower attack time on variable MU that can help you glue your track together and can give you really balanced and smooth mix.

Best variable mu compression plugin

Below are some of the topmost famous and best Variable MU compressor plugin that you can look into and they provide the top quality sound.

1. arturia comp tube-sta

The original Gates STA-Level Tube Compressor is the one that inspired Arturia to produce the Comp Tube-STA. That means the quality that you are going to get will be outstanding.

This plugin is compatible with both Mac OS as well as Windows OS and comes in all AAX, AU, and VST formats.

Recreated from the best digital plugin American Tube Compressor, Arturia’s Comp Tube-STA is one of the best audio compressors that are available in the market. With an easy-to-use format, this plugin apprehends the charming vintage tone that comes with simplistic controls and flexible execution.

2. Softube Summit Audio TLA-100A

When you read the full name, you understand that this plugin would have the superb summit TLA-100A Tube Leveling Amplifier.

Again, like every other compressor plugin, this is also compatible with both Mac OS as well as Windows OS and comes with the AAX, AU, and VST formats.

If we talk about Softube, it has done a tremendous job in modeling the gentle, natural-sounding gain reduction and sublime leveling of the user-friendly TLA-100A. This plugin is great as it offers seamless effort control over signal dynamics and that also without flattening the sound.

You can check out this plugin if interested because of the quality of the sound you get, which will be outstanding and seamlessly smooth.


I would suggest, if you are just a beginner and started the mixing game just recently, you don’t need to go too deeply to the finer points of the types of audio compressors. Always think and understand the sound of any instrument that you want it to sound while recording.

The main point here is to keep on doing the experiment on different plugins. There is no white rule that you need to follow to get the perfect sound that you have in your mind. You will be needed to try every types of audio compressors and plugin in order to find out the perfect sound.

But after all this, you didn’t get your sound perfect, comment down below and we’ll give the alternate solution for the same.


Are all compressor plugins the same?

My overall answer will be NO, all the compressor plugins don’t sound the same. When you start interacting with the knobs for input on the compressor plugins, you will realize the difference between each plugin.
They all have to offer different types of quality and functions to provide variation in the sound quality. When you get familiar with the plugin, you are going to understand the difference in the sound quality. So keep on experimenting with very types of audio compressor plugins.

What does a noise gate do?

The work of a noise gate is to block any sound or noise coming from the audio channel when you set a noise threshold. When the sound goes too down below the threshold, the gate gets closed and blocks any noise. But when the sound gets louder than the threshold, the gate gets open and allows the sound to pass through.
There are four common parameters that a noise gain plugin has, Following are they:
Threshold, Attack, Release, and Hold. Each one of them has its own duties to do.

What is an audio limiter?

The audio limiter most often acts as same as the audio compressor but with a few short differences. A limiter happens to take the compression to its extreme level and gives more use in the mastering process than that on the mixing one.
As you can understand by the name ‘Limiter’ it has the ability to apply the limit or cease to the output level. If we talk in other words, no sound beyond the given threshold will pass through.

Which type of audio compressor is the fastest?

Among the four types of audio compressors, (FET Compressor, VCA Compressor, Opto Compressor, Variable MU Compressor), FET Compressor is considered to be the fastest. As the name itself suggests, FET compressors are the one that relies on the transistors for gain reduction.
The attack and release time can be set instantly, as this compressor is incredibly fast.

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If You Want To Mix Your Music Like Professionals,
You Have To Learn From Professionals And We Have Made It EASY For You.​

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