Ableton Sidechain Compression

Ableton’s stock plugins are as good if not better than a lot of the premium offerings out there. If you want to use sidechain compression, Ableton has you covered as part of their stock compressor plugin. Here is how to use Ableton sidechain compression.

Ableton Sidechain Compression

Here are the settings I recommend when using Ableton sidechain compression, then we’ll go through how to set it up and why we picked the settings we did:

ableton sidechain compression

First, let’s pick a track in our mix to use the Ableton sidechain compression with.

The most obvious subject is our bass track.

As I covered in my guide on how to EQ kick drum, the bass and kick should be mixed side by side because they share a lot of similar frequencies.

Getting your low end mixed properly is one of the best ways to remove mud from your mix. This includes creating complimentary EQ cuts for the kick and the bass (see my bass guitar EQ guide).

Another way to help the kick and bass work together is to use sidechain compression on the bass.

This means adding a compressor to the bass track which engages based on the behavior of the kick instead of the bass. We should still compress our bass guitar with a dedicated compressor. Our sidechain compression will be done with a separate compressor.

Step 1 – Drop Compressor on Bass

For this example we’re compressing our bass based on the kick’s behavior.

The idea is that the bass gets compressed when the kick plays, thereby ducking the volume for a split second. This allows the kick to have the low frequencies all to itself whenever it plays.

Step 2 – Chain Compressor to Kick

To access the sidechain options, click on the arrow in the top left of the plugin to expand it.

ableton compressor

This reveals the sidechain section where we can select the instrument we want to act as the source. Click “No Input” and find and select the kick track.

Ableton Sidechain Compression Pre FX Post FX and Post Mixer

You’ll notice underneath there’s another field which contains three choices: Pre FX, Post FX, and Post Mixer.

This determines which stage in the processing chain the compressor uses as the input for that source. This works with our threshold which we’ll talk about in a moment.

Pre FX means that it takes the level of the raw audio of the kick as the input. Regardless of any plugins we have on the kick track or wherever the fader is set for it, the sidechain compressor on the bass will just use the gain of the raw audio itself as the input.

Post FX means that it takes the level after the last plugin in the chain. So any changes to the gain which EQ, compressor, and other plugins cause, the level at the end of all of that processing is our input level.

Post Mixer goes by the level of the track after the fader as the input. So if you have the fader turned all the way down on the kick, the compressor on our bass won’t engage because it’s not getting any signal.

By default, Post FX is selected. If you do any automating of the level of your source (in this case, our kick), you should keep that in mind when selecting which input level option you want.

Step 3 – Adjust Your Sidechain Compressor Settings

Now that we’ve got our sidechain properly routed, we just need to set the parameters for the compressor itself.

ableton sidechain compressor

I generally go with the same settings as I outlined in my bass guitar compression guide. This includes:

Threshold – Set this low enough so that it’s always triggered by the kick. We don’t want to set it at the floor so that the slightest ambient or bleed noise triggers it. Just go as low as the quietest kick hit.

Ratio – An above average ratio 4:1 will create a decent reduction of the gain on our bass to get it out of the way.

Attack – A fast attack of 1ms or less ensures that the compression engages quickly so that the bass in turn gets out of the way quickly.

Release – A relatively quick release of 50ms is fast enough to get the bass to come back after the kick has finished but not so fast that it sounds odd. This creates a gentle enough on ramp of a slope to get our bass back.

Out – The “Out” is our output gain. You shouldn’t need to adjust this on sidechain compression because the gain reduction is the whole point. The gain reduction is only enforced when we want it (to duck out of the way) rather than being more of a constant level attenuation like on a normal compressor. Speaking of which, make sure you leave the automatic makeup gain turned off.

Ableton Sidechain Compression Tips

  • Ableton sidechain compression allows you to duck a more static track to make room for another.
  • A common and effective application of sidechain compression is to have your bass compressed based on the behavior of your kick.
  • Drop a compressor on the track you want to compress/duck. Click the arrow in the top left and specify which track you want to create room for. This is the track whose behavior will trigger the compressor.
  • Pre FX, Post FX, and Post Mixer determine the input signal of the source track based on the raw audio level, the level after effects, or level after the fader, respectively.
  • Set the threshold to trigger at the quietest moment of audio of your source track.
  • Set the ratio at 4:1, attack at 1ms, and release at 50ms. This creates fast and adequate gain reduction which recovers quickly yet naturally.
  • Leave the auto makeup gain turned off and don’t add any makeup gain manually. The gain reduction is only when we want the track to duck out of the way.

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  1. Pingback: What is Post FX vs Pre FX and Post Mixer in Mixing - Music Guy Mixing

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