What is sidechaining used for

If you act stupid and your mom smacks you, that's the normal expectation. But if your brother acts stupid and your mom still smacks you for it, that's sidechaining! The obvious next question is "what does sidechaining do?

What you have to understand it's all based on which audio effect you're using, whether in plugin form or hardware in your rack. Many effects units can accept a sidechain, and that changes the real answer.

But roundabout answer is that it allows you to use a separate track as the trigger for an effect on the main track. Let me give you a real world example based on the most common usage, which is sidechain compression. We've all dealt with a bass drum and a bass line that simply won't get out of each other's way. You've compressed the kick drum to have more attack. You've tried to carve out a dominant frequency range for both. But regardless, it's still a muddy mess where it's hard to make out the kick due to the bass playing behind it.

In the case of sidechain compression, we'd assign a compressor to the bass track but select the kick drum bus as the sidechain.

This makes it so that the bass will be compressed only when the kick drum occurs. You can see this in the image below. This is called ducking and is the act of making the bass' volume reduce itself whenever the kick fires off. When done subtly, the listener won't notice the bass line's volume dropping but it will add a ton of clarity to the kick. Let's look at more examples and it'll all start to make more sense.

Let me say, though, that setting up a sidechain is often as simple as finding the dropdown box on your plugin's user interface most will have this option and choosing a bus or track as the input the one giving the directions.

In the image above, we're looking at the stock compressor plugin from Logic Pro. You can see at the top center that I've applied this plugin to the "Bass" track. At the top right where the arrow is pointing, there is a dropdown menu where I can choose either live inputs from my audio interface or a bus on the mix.

I chose the "Kick" bus, though it doesn't show the name. This is a free, stock plugin. You can rest assured that any plugin for an effect capable of using a sidechain usually just gain reduction units will have the option, especially premium, paid options. A VST that can have it will have it. If you record your overheads and you find that you have too much snare sound in them, you can simply set up a bus on the main snare channel.

Send the bus to a compressor on the overheads. Now, every time the snare drum hits, it will trigger the compressor and duck the snare down in the overheads. When the snare is not playing, your cymbals will be uncompressed. This is a simple effect to set up. If you find yourself at the end of the song, and the lead guitar and vocal are both wailing away at the same time, this will help you mix them together.

Send your vocal to a bus. Make that bus the key or sidechain input on a compressor that is on the lead guitar track. As soon as the vocal comes in, it will trigger the compressor on the guitar track and duck the guitar by an amount you set with the threshold. Before the days of de-essing plugins which are now incredibly handy, you could make a de-esser by sidechaining an EQ to a compressor. Sidechaining is a production technique used in a wide variety of music genres where an effect is activated by an audio track.

The alternative source is set to a threshold, which when exceeded activates the effect. One of the most common examples of this is when radio DJs are talking over some background music. Noise gates are some of the most helpful tools in mixing.

But just like compressors, changing the signal in the detector path with the sidechain input makes them even more useful. When you use multiple microphones to record a drum set, some of the sound from the kit will bleed into the close mics on each drum. This problem happens all the time when you record a bass drum with an inside and outside microphone. However, if you use the inside kick drum mic as the sidechain input, the gate will use this cleaner signal to decide when to let material through.

Insert a gate with sidechain input on a sustained sound like an ambient synth pad. De-essers are an important effect in any good vocal chain. They help reduce the negative effect of sibilance in a vocal recording. Hot tip : Sibilance is most distracting in the upper-mids and highs, between 2. Experiment with filtering out everything outside a narrow part of this range to isolate the sibilance.