{"id":1603,"date":"2021-08-16T11:00:00","date_gmt":"2021-08-16T11:00:00","guid":{"rendered":"https:\/\/mixxed.com\/blog\/?p=1603"},"modified":"2022-09-22T11:46:53","modified_gmt":"2022-09-22T11:46:53","slug":"how-do-compressors-work","status":"publish","type":"post","link":"http:\/\/create.routenote.com\/blog\/how-do-compressors-work\/","title":{"rendered":"Compression Explained: How Do Compressors Work?"},"content":{"rendered":"\n

What is Compression in Music Production?<\/h2>\n\n\n\n

Compression<\/strong> is used to control<\/strong> the dynamic range <\/strong>of an audio signal<\/strong>. Maybe you wanted to change the dynamic range of a loop you’ve made with Mixxed<\/a><\/strong> samples? Well, we’re going to show you how!<\/p>\n\n\n\n

Dynamic range <\/strong>is the difference between <\/strong>the highest and lowest levels <\/strong>of amplitude <\/strong>in any given signal. So, you’re reducing <\/strong>the difference between <\/strong>the highest and lowest levels <\/strong>by lowering <\/strong>the highest points <\/strong>and maintaining <\/strong>the lower volume points <\/strong>to maintain a consistent level <\/strong>across an entire audio signal<\/strong>.<\/p>\n\n\n\n

In music production, we can use compression to do a few things, but we’re going to cover that later. We’ll also cover the different types of compressors in good time!<\/p>\n\n\n\n

You’ve made some killer sounds through our Define Synthesis<\/a><\/strong> series, but need to tame crazy transience? Let’s focus on the compression<\/strong> basics <\/strong>and ease ourselves into this wormhole of information!<\/p>\n\n\n\n

Explain Compression<\/h2>\n\n\n\n

5 Types of Compression and When to Use Them<\/a><\/strong>

What is Compression Used For?<\/a><\/strong>

What are the Different Types of Compressors?<\/a><\/strong>

Top 5 Compressor Plugins to Help You Control Dynamics<\/a><\/strong><\/p>\n\n\n\n

What Does Threshold do in Compression?<\/h2>\n\n\n\n

What is the threshold in audio compression?<\/strong> A threshold is an amplitude you want your signal to reach before your compressor engages<\/strong>.<\/p>\n\n\n\n

For example, if you wanted your input to reach 10dB before <\/strong>the compressor kicks in<\/strong>, the threshold <\/strong>is how you set that parameter<\/strong>. The threshold tells your compressor <\/strong>“yep, this is loud enough now” and your compressor brings the volume down<\/strong>, which reduces the dynamic range <\/strong>of the signal.<\/p>\n\n\n\n

If your signal doesn’t reach the amplitude <\/strong>at which you have set your threshold<\/strong>, the compressor will <\/strong>continue to sleep<\/strong>. On the flip side, if your signal <\/strong>is consistently above <\/strong>the threshold<\/strong>, your compressor won’t sleep <\/strong>at all!<\/p>\n\n\n\n

As your signal begins <\/strong>to drop below <\/strong>the set threshold<\/strong>, your compressor disengages<\/strong>. <\/p>\n\n\n\n

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Source: mynewmicrophone.com<\/figcaption><\/figure><\/div>\n\n\n\n

Let’s jump in with a visual example.<\/p>\n\n\n\n

Above is a representation <\/strong>of an audio signal <\/strong>and threshold markers<\/strong>.<\/p>\n\n\n\n

The red dotted line <\/strong>is your threshold settings<\/strong>, time <\/strong>is represented along the x-axis <\/strong>& amplitude <\/strong>on the y-axis<\/strong>. <\/p>\n\n\n\n

When you compare <\/strong>the original signal against <\/strong>the compressed signal<\/strong>, you can see that the amplitude <\/strong>is only attenuated <\/strong>in the segment of audio <\/strong>that crosses over the red dotted <\/strong>line\/threshold. <\/p>\n\n\n\n

If you’re still not entirely confident, here’s another example.<\/p>\n\n\n\n

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Source: Icon Collective<\/figcaption><\/figure><\/div>\n\n\n\n

For now, ignore the ratios <\/strong>and focus <\/strong>on the threshold line<\/strong>. But to save any confusion, a ratio of 1:1 is no compression whatsoever. <\/p>\n\n\n\n

We can see that the input level <\/strong>is represented on the x-axis <\/strong>and the y-axis <\/strong>represents the output level<\/strong>. <\/p>\n\n\n\n

Before <\/strong>the threshold line<\/strong>, we can see that the input <\/strong>& output <\/strong>levels are exactly the same<\/strong>. Once the threshold line <\/strong>makes an appearance, the output level <\/strong>is dipped <\/strong>(and you can see that the amount of compression <\/strong>is set by ratio<\/strong>).<\/p>\n\n\n\n

What Do Compressor Attack and Release Settings Do?<\/h2>\n\n\n\n

What is the attack time of a compressor<\/strong>? The attack time is the time it takes for the compressor to engage once the audio signal passes your threshold parameter.<\/strong><\/p>\n\n\n\n

Attack defines <\/strong>the time it takes <\/strong>for the compressor to meet <\/strong>its full volume reduction <\/strong>ratio after <\/strong>the threshold <\/strong>has been passed by the signal<\/strong>. <\/p>\n\n\n\n

Release<\/strong>, if you haven’t guessed, is the time it takes <\/strong>for the compressor to disengage <\/strong>once the signal has dropped below <\/strong>your threshold parameter<\/strong>. <\/p>\n\n\n\n

Therefore, a fast attack time <\/strong>such as 0ms <\/strong>(milliseconds) engages the compressor <\/strong>as soon as the signal bypasses your threshold<\/strong>, and a slow release time <\/strong>like 20ms will keep the compressor engaged <\/strong>for this long when the signal drops below <\/strong>the threshold<\/strong>… and vice versa.<\/p>\n\n\n\n

However, slow attack <\/strong>and release times aren’t the same as delayed triggers <\/strong>where they wait for 20ms <\/strong>to go by before engaging<\/strong>. Instead, slow times means <\/strong>the compressor will gradually engage and disengage <\/strong>over a 20ms timespan<\/strong>. <\/p>\n\n\n\n

The use of a slow attack time<\/strong>, for example, will keep the compressor engaged <\/strong>when the signal has dropped below your threshold<\/strong>. This means the compressor <\/strong>will be compressing <\/strong>the quieter parts <\/strong>of your signal <\/strong>too. <\/p>\n\n\n\n

<\/p>\n\n\n\n

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Example of attack times, Source: mynewmicrophone.com<\/figcaption><\/figure><\/div>\n\n\n\n

Attack and Release Can Have Consequences on Your Compressed Audio<\/h3>\n\n\n\n

So, a slow attack <\/strong>may mean you end up compressing your quieter signals<\/strong>. But what about a very quick attack?<\/p>\n\n\n\n

Should you choose to use an attack with 0ms<\/strong>, you may well affect the shape of the waveform <\/strong>itself rather than bring the peaks down<\/strong>.<\/p>\n\n\n\n

Imagine a hammer hitting a nail<\/strong>. If you use one big hit <\/strong>to drive it into the wood<\/strong>, you risk bending the nail <\/strong>rather than sinking it into the wood<\/strong>. But if you hit it with less velocity <\/strong>over multiple hits<\/strong>, you are far more likely <\/strong>to send it down instead of bending it<\/strong>. <\/p>\n\n\n\n

This can be useful for some percussion sounds like drum samples, but not always not for guitars or synths.<\/p>\n\n\n\n

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Source: mynewmicrophone.com<\/figcaption><\/figure><\/div>\n\n\n\n

Above is an example of what could happen <\/strong>with the use of 0ms attack times<\/strong>. Notice how the compressor has flattened the peak <\/strong>of the waveform rather than <\/strong>the lower the smooth curve <\/strong>of the input signal<\/strong>. <\/p>\n\n\n\n

With most things, there’s a yin and yang here. <\/p>\n\n\n\n

The x-axis represents time<\/strong>, so you need to bear in mind <\/strong>that there are attack times <\/strong>that will be too long<\/strong>. <\/p>\n\n\n\n

With an attack time that’s too long<\/strong>, your compressor won’t reach full attenuation <\/strong>because the signal will drop below the threshold before it has a chance to get there<\/strong>. Experiment and trust your ears<\/strong>. Let them guide you. <\/p>\n\n\n\n

What Can Attack and Release Settings Do For My Sound? <\/h4>\n\n\n\n

Setting the right attack & release parameters are important for the final effect on your sound. Here are some examples of what attack and release can do to your signal, written by mynewmicrophone.com<\/a><\/strong>.<\/p>\n\n\n\n