Sidechaining Effects and Adding Atmosphere to a Synth in Ableton Live

One of the most important techniques to learn in music production is sidechain compression.

Many people have a love/hate relationship with it due to the fact that it’s often overused, especially by newer producers. Despite this, there’s no denying the fact that it’s a powerful tool to use for being creative and/or improving the mix.

In this post, we’re going to be looking at how we can sidechain certain effects such as reverb and delay to a synth sound.

If you prefer to read/look at images, then feel free to skip the video and continue.

Note: We just published a more recent and in-depth guide to general sidechain compression – check it out here.

Step 1 – Setting Up Your Sound

Realize that this won’t work well on every single type of lead sound. If you have a long, continuous, legato type sound – then there isn’t much point in sidechaining reverb or delay to it, as the sidechain signal will be playing the whole time, disallowing the effects to cut through.

For simplicity’s sake, I’m not going to show you how to make the pluck sound I’m using in this tutorial. Feel free to use a preset or make your own!

Here’s a screenshot of the MIDI with an audio clip of how it sounds (without effects).

Note: I’ve folded the piano roll to make everything more visible. The chord progression is from the song ‘Audien ft. Ruby Prophet – These are the Days.’

Midi chord progression
Click to enlarge

Here’s how it sounds.

Why Sidechain?

The main problem that occurs when placing reverb on top of a sound is that it can strongly alter the original sound. Often you’ll have a nice synth patch that just needs a touch of reverb for atmosphere, but when placing reverb  on the same channel, you seem to lose a lot of character.

Here’s the original pluck sound with reverb placed directly on top (not sidechained)

In this case it’s not overly bad, we can still hear the attack of the pluck sound and its tone – but it’s really muddy due to the decay of the reverb overlapping with the original pluck sound. If we were to sidechain the reverb, we’d reduce muddiness and enable the pluck to punch through more.

Step 2 – Mixer Routing

For a newbie, mixer routing can be daunting. Fortunately it’s quite straightforward.

We’re going to be using Ableton’s session view for this.

audio routing1. Click the I-O button near the bottom right of Ableton to bring up the audio routing section in the mixer. You should see something like this.

2. Change the ‘Audio From’ section (the first drop down) to track one, or the track that your original synth sound is on.

3. Finally, change Monitor to in. When clicking play in Ableton, you should hear the sound coming through both channels.

Step 3 – Draft Effects

There’s no point trying to perfect our sidechain compression without being able to actually affect any sound. We’re going to add some reverb to our second channel (the channel that we’re feeding audio into).

It doesn’t have to be anything too complicated. Feel free to copy the settings from the image below.

reverb settings

Adjust it according to your original synth sound, but make sure you have the dry/wet knob turned to 100% otherwise you’ll get the original synth bleeding through which is unnecessary.

If you play the sound now, it’ll still be pretty ugly. The reverb is playing simultaneously with the synth, causing muddiness.

Step 4 – Sidechain Compression

Now that we’ve got some sort of sounding coming out of our second channel, we can start to manipulate it.

Sidechain compression is simple to understand, but takes practice to get perfect. I’m not going to venture into all the details now, if you’re a beginner I recommend reading up on compression to understand the specifics, such as the attack, threshold, ratio, and release parameters. For now, follow these steps:

1.  Click the arrow up near the top left of the compressor to bring up the ‘sidechain’ section. Choose your original synth sound as Audio From. 

2.  Play the full sound along with the reverb track

3. Slowly pull down the threshold fader until you have a nice ‘duck’ in your reverb (note that the reverb needs to be placed AFTER the compressor)

I used these settings:

compressor settings

If you’d like to see visually how sidechain compression works, change the compressor over to the Activity tab (left of where it says Knee 6.0dB). You’ll see that the signal ducks when the synth sound plays.

We’ve now got our reverb ducking. This is how mine sounds:

Step 5 – Adding Parallel Delay (Optional Step)

Parallel just makes it sound complicated, but it’s really not.

If you add a ping pong delay to the reverb channel, before or after the reverb – you’ll find that it doesn’t include the attack of the pluck, or the body of the pluck. All it does is affect the reverb, or vice versa.

There’s a simple way to fix this – you can either duplicate the sidechained reverb track and replace the reverb with a delay, OR you can use an audio effect rack.

Adding Delay with an Audio Effect Rack

Step 1

Drag and drop an audio effect rack into the sidechained track that has your reverb on it. After doing so, drag the reverb into it and then click the chain icon as shown below.

audio effect rack

Step 2

After bringing up the ‘chains’ section, right-click below the initial chain with the reverb, and click ‘Create Chain.’

Now you can simply add your delay to the second chain, and it won’t be affected by the reverb!

This is a similar process to making two mixer tracks and having the original sending out to two, but it saves CPU processing and a mixer track.

Tips, Tricks, and Conclusion

I recommend playing around with the settings on the compressor and especially the reverb. This is a great sound design tool and does not only need to be used for reverbs and delays; you could go ahead and sidechain a bitcrusher or saturator. The possibilities are endless!

All in all, it’s a great way to add some atmosphere and ‘life’ to your synth tracks. Here’s a before and after comparison.



Got any questions, comments, or suggestions? Let me know in the comments box below.


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