It’s quite confusing for newbies when it comes to differentiating between compressor VS limiter. This article will help you with that.
Wondering, what’s the difference between a compressor and a limiter? Well, it’s a common question among the audio recording enthusiasts. As both of them fall into the same category ‘dynamics processor’. even they look similar too. But their functionality and use are different.
In this article, we will discuss the difference between the compressor and the limiter.
But first, let me answer this question that what’s the basic difference between compressor and limiter?
The only basic difference between the compressor and limiter is the compression ratio used in them. In Limiter, a higher compression ratio (anything above 10:1) is used along with the threshold close to the desired audio level to limit the maximum level and provide overload protection, wherein the compressor, low compression ratio (below 5:1) and threshold level is used to control the uneven dynamics more accurately such as in vocals where the uneven dynamics are very common.
Got any idea of compressor and limiter?
Well, I know you not just searching for the basic definition but some advanced knowledge of both compressor and limiter, that’s why you are here.
Read on, I will be providing you with all the details of compressors and limiters.
Compressor VS Limiter: Differences You Should Know
I’ve divided this article into several different sub-topics that will help you to solve this puzzle.
- Compressor VS Limiter: Differences You Should Know
- How Does Compression Works?
- What is Limiter?
- Types of Compressors
- Types of Limiters
- Conclusion: Compressor VS Limiter
Now let me explain these sub-topics one by one.
How Does Compression Works?
In a compressor, generally, you will find six types of controls.
- Attack time
- Release time
- Make-up gain
However, all these controls are important but understanding the work of compressor you only need to understand the two – Threshold and Ratio.
To make the compressor work properly we need to tell it how it will reduce the dynamics of our instrument. To achieve this goal you need to set up the threshold and ratio for,
- WHEN to start compression.
- AMOUNT of compression.
Let’s get some knowledge of the 6 controls of the compressor.
Do you know, what threshold does in compression? Here it is – Threshold decides when to start the compression. It determines, after how much loudness compression will start kicks in. In simple words, the compressor doesn’t reduce the signals’ volume until it reaches the threshold.
Threshold is measured in dB and you are always in negative measurement such as -1dB, -6dB etc. Now let us take some practical example.
Assume you have recorded a vocal that’s overall dynamics is around -14dB but in some portions of the vocal the singer went extra loud and you get spikes up to -10dB. Here if you set the threshold around -13dB then whenever the vocal becomes louder then -13dB compressor kicks in under the range.
Ratio is another important control of the compressor. It tells the compressor about the amount of compression. That means how when the compressor kicks in how much it will turn the signal down.
Let us take an example – Say you have set up the threshold -16 and your ratio is 2:1. That means whenever the vocal reaches -14 dB the vocal will be turned down by 1 dB. If the vocal reaches -12 dB then the signal goes down by 2dB.
The rule of thumb is if you want to compress more you should be set the higher ratio(4:1, 6:1 etc) and if you want less compression you should set the ratio lower (2:1, 3:1 etc)
Ohh, this math is complicated for you, don’t worry I also don’t like math.
The simplest formula is – When you lower the threshold and/or increase the ratio you are compressing hard and when you go just opposite that means to increase the threshold and/or lower the ratio the compressor goes soft.
When the compression is applied in the correct way, you can increase the volume of the vocal WITHOUT CLIPPING.
Note: You should always match the RAW signal volume and processed signal volume by adjusting the makeup gain control.
So, if the compressor is able to stop the clipping, why and where a limiter is used?
Let’s get the answer…
Why a Limiter is Used?
First, you need to know that just like compressors, limiters have also a threshold parameter. But it’s threshold works differently then compressors.
Apart from a compressor, limiter won’t let the signal get any louder than the threshold. If you set the threshold at -1dB then the signal never goes louder then -1dB. That’s the reason why limiters also called brick wall limiters.
So, how do limiter do that?
Well, as in the beginning you’ve read that limiter has a very high ratio, generally above 10:1. That means it acts like a brick wall whenever the signal goes louder than the threshold.
As simple as – Ratio is the main difference between compressor and limiter. The compressor has a low ratio where limiter has an extremely high ratio.
When You Should Use Compressor?
Compressors are used with individual instruments such as guitars, drums, and vocals.
As the instruments and vocals are too dynamic in nature, we can’t use limiters with them. If we use limiters with individual instruments, its strong ratio would squash the overall dynamics of the instrument.
Where the lower ratio of the compressor allows you to control the dynamics without letting the listener notice the change.
It’s not necessary to apply the compressor in the individual instruments that really don’t need it, however, you should always analyze the dynamics if it needs the compressor or not. In most cases, the compressor is applied in all the instruments and vocals.
Applying the compressor also depends on the genre of the song as in jazz where or classical you just need a little compression wherein Rock or Rap you need an extra hard compressor.
Here is a useful article on compressor settings for vocals.
When You Should Use Limiter?
The mix bus and master channel is the only place where you should use the limiter.
Note: If you are going to send your song for mastering, don’t put any limiter in the master. Only use it if you want to master the song yourself.
Here is a step by step procedure to use the limiter in the mix bus.
- Add the limiter at very last of the mix in the master channel.
- Set the output (ceiling) at -0.5 to -0.2.
- Increase the input gain about 10 to 10dB.
- Set the attack at 100ms.
- Set the release at 500ms.
- Now start decreasing the attack slowly until you hear the mix started to lose the impact.
- At the point where you get the release losing impact turn back the attack a little.
- Decrease the release slowly until you hear the sound gets distorting.
- At this point back of the knob a bit.
- If you have an auto function, let the compressor do it for you.
- Now decrease the input gain until you are getting 2dB to 3dB reduction gain.
That’s it, the limiter is all set in your master.
Note: If you are using the DAW’s own limiter always aim for 1-3 dB’s of gain reduction and if you are using any third party limiter always aim for 1-5 dB’s gain reduction.
Caution: Anymore then 2dB of gain reduction your song gets started pumping, so beware of too much gain reduction.
Limiters are also used with bass guitar where you need to make its dynamics more even as it is the building material of the harmonics of a song. You can also use limiters in heavy drums.
After all, the sky is the limit. You always be as much as experimental in music.
Conclusion: Compressor VS Limiter
Well, you’ve read the differences between compressor and limiter.
The end goal of this article is to make these two tools more handy for you. I hope after reading this article you are now more clear that when you should go for compressor and when for the limiter.
Although, I’ve mentioned above that limiters are made for mix bus, but there is no hard and fast rule of using it only there. You just need to decide where you need a high ratio and where the low ratio.
Okay, I hope this article would have been informative for you. If you like it, share it on your social circle and if you’ve any question, comment below. I will answer all your questions regarding this topic.
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Gautam Roy is a recording engineer and a blogger from India. He loves music, writing and travelling. He is also an active investor and a successful entrepreneur.