To generate free content for you when you purchase through links on our site, we may earn an affiliate commission.

What is Parallel Compression, and how to use it?

what is parallel compression

In the old days, if you released a good song, even with a good sound, it had the potential to be a good song. A good song is the total of an excellent melody, quality production, and a hit sound. Parallel compression is an indirect processing technique of sound that is not applied to the source channel. We will discuss and explain the technique and expand on the standard methods of using it.

What is Parallel Compression

Parallel compression is an advanced compression method in the mix. The principle behind the method is to leave the original sound clean, without compression or with minimal compression, apply the desired compression to a parallel channel of the same sound, and merge the two channels in a balanced way.

 The method also exists in other effects in addition to the compressor. You must have asked yourself what advantage there is in doubling the same channel instead of applying the compressor to the same channel. 

Let’s go over the most important reasons:

What are the benefits of parallel compression?

1. Keeping the source clean

Although we apply effects, sometimes even extreme ones, on the source channel, there are things that we prefer not to put on the sound itself but to duplicate and combine it. This will prevent problems with the volume of individual channels, reaching clipping, and over-processed sound, which will lead to a decrease in sound quality.

2. unique sound

Many techniques are used in sound today to reach a perfect level of finish. Parallel compression is one of the well-known techniques to go into small details in each sound and compress large parts with additional effects. We will further explain all the uses, but only as an example. 

There is the use of parallel compression after EQ with a broad frequency change. The goal of compression is to make the frequency change noticeable in RMS and less in Peak and thus prevent an excessive loudness master.

Typical uses of parallel compression

Any compressor you want to apply to the source channel, or any dynamic operation you thought of testing, will work great in the parallel channel, and I would highly recommend you to try new things because this method opens a door into deeper and subtler layers of the sound, but of great significance in the overall sound. 

Let’s take Billie Eilish as an example. I’m sure you know her, her brother produces the songs for her, and he revealed to Rolling Stone some of the methods in his mix that sound so warm and close, so, for example, the entire vocal goes through a lot of parallel processing, which gives it the warmth and feeling you hear every Her breath. 

Even instruments like bass (even a simple sub) can get interesting additions by compressing them in parallel. This is a little background on working with the method. Now let’s dive more into the specific methods.

Gentle compression


We want some kind of compression but can’t manage to do something that won’t kill the sound. Do you know the conflict? So here, parallel compression will be your saviour because the source remains clean even if you compress with a relatively strong compressor. 

You can control the level of the effect by using the correct dosage with the source channel. This will instantly give you beautiful dynamics and, on the other hand, a tight sound.
So how do we do it? 

Let’s take as an example drum (a whole kit) that has already been mixed individually and compressed individually. Now we want to give the drum group more colour from a certain compressor but are afraid that it will damage the drum sound, so, first of all, let’s break down the channel (check how to do the It’s in the mixer of your DAW, it should be very simple). 

We’ll lower the fader of the parallel channel and apply the effect we’re interested in and the parameters. Finally, we’ll gently start raising the fader until we hear the second sound as well. Here it’s your decision. How much would you like to spend?

Compression after EQ


We added EQ to compensate for some lack of sound, but because it has to be a bit extreme, it also has a negative effect in some ways. What can we do? For this, there is a compressor that will highlight the sound only in the centre of the sound and will not cause problems with other frequencies. All of this (both EQ and compressor) we must do in a doubled channel of the source. 

This way, no matter what frequency range and how much we want to raise, it will not damage the original sound but will be combined in the correct dose. 

As an example, we have a vocal that lacks a little presence in the voice, so we want to increase the 700-1kHz area, we will open another channel and route the source to it, we will apply the change in EQ without fearing the volume, and after that, we will apply a relatively strong compressor that will keep it only in the right place. Without delay in the attack and with a relatively smooth release.

Punchy sound


Again, we want to make a sound stand out in the mix. Still, directly on the sound, we have to apply a compressor with a long delay before attacking will affect the rest of the sound in a wrong way, and we may need to get a better result. Let’s demonstrate this on a kick.

 We want it to be more punchy but still have a stable body. With parallel processing, we can do it without a problem, and it has a beautiful effect on the sound.


Optimisation for small / bass-less speakers


You know that when you finish a mix and you go to listen to it on a different system, from personal headphones, your car, and the television. Still, unfortunately, it doesn’t sound as good as it did in the studio. Usually, the big problems are manifested in the low-end lack of bass/too much bass, and we need help fixing it! ,Parallel processing can be your saviour.
Try the following steps if you are missing bass:

  • Duplicate the channel of the bass in question.
  • Apply an over-drive effect or any distortion you like, but very gently.
  • Put a relatively fast compressor after it with average compression
  • Start raising the fader and see the magic.

In two words, what we did here: So, in medium to small speakers, the bass area is almost completely absent, compared to the middle range, which dominates this type of speaker. That’s why we took a harmonic enrichment that will give us a little more aggressive midrange so that the bass will stand out even in smaller systems. (Note that you check this in the Normal sound system That doesn’t sound too distorted).


Vocal presence


Sometimes, we want to make the vocal feel more central and controlling, but we can’t get good results on the original channel, so we can do it on a separate channel. We can do compression in combination with EQ or compression alone. It doesn’t matter because every action we do on The replicated channel will only have a partial effect, so of course, you have to learn how to apply parameters subtly even if you do parallel compression, but still, everything will be more doable.
Here are simple steps to get tighter vocals:

  • Duplicate the original channel.
  • Apply a compressor with a long attack delay, quick release, and a relatively still threshold.
  • Apply EQ before, with a boost in the 1.5 – 2.5kHz range, to make the sound stand out in the mix (optional).
  • Start raising the volume of the channel


Best compressors for parallel compression

Parallel Aggressor

baby audio

SPC2000 comp

U73b Compressor

FAQs on parallel compression

Is parallel compression good for vocals?


It’s hard to say this unequivocally, but it’s hard for me to find a song from these days that didn’t have some kind of parallel processing. It’s a method that provides so much deep access to the elements in the sound that you don’t commit to it, that there’s no reason not to use it in the vocals. 

For example, you can highlight the vocals In the mix as we explained above, and even if you just want to apply distortion to the vocal to give it warmth but don’t want the original to be damaged and get a completely different colour, a parallel is a way!

Is it possible to do more than one parallel on sound?

For sure! In principle, it is possible to do several parallel processing on each sound as long as it is not over-processing. For example, with the vocal, we want to do one channel to apply compression and on the other channel to add a unique reverb.

Finel words

Parallel compression is one of the advanced methods used by producers, and sound professionals in order to reach a higher level of sound quality and grammatical abilities in details, you too have adopted the method to align with a standard in the audio world.

Get more quality reviews