Sidechain In-Depth Tutuorial

[Malcolm MiddletonParticipant]

I really need a sidechain tutorial! I just can't fully get my head around it and I know that sounds stupid.

[Guido tum SudenKeymaster]

No, it doesn't. It took me a long time to understand the concept. In the end I think it was because there are two types of sidechains and when you get to know it from a computer's perspective, which I did, the name "sidechain" doesn't fit to one of them, at all.

1. The easier to understand one first. External sidechain. I'm using Logic, but AFAIK it is similar in most DAWs. Some plugins, most compressors in fact, have a sidechain menu in their header. If you click it you get the existing channels of your DAW, often also the busses. You pick one (but not the channel with the plugin you're using). When you playback your DAW, whatever is played from the channel you picked, is branched off to the plugin and does something there.
What it does depends on the plugin (read the manual). If it's a compressor it most always effects its threshold.
The louder the signal from the sidechain channel is, the more the threshold of the compressor dials in, or the more the compressor compresses the signal.
A typical scenario: the compressor is on a bass channel, the sidechain signal comes from the kick. When the kick is played, the compressor kicks in and the bass is turned down and so doesn't compete with the kick at that point. How fast the bass gets quieter and louder again, you can adjust with the attack and release of the compressor.

2. Internal sidechain. For me the name sidechain is misleading, because the sidechain signal is not from a different track, it is the signal, that goes into the plugin. At first that doesn't make sense, because how could a signal effect itself?
These internal sidechains, as well as some of the external ones, alway have a kind of filter. Mostly it's a simple EQ, often only a high and a low cut.
Example: You have a drum pattern in stereo or mono. The snare is too loud. You could use an EQ to make it quieter, but that will also change the sound of the snare. Now you use a compressor with an internal sidechain. When you use it without the sidechain it wouldn't work, because if you set it in a way that it triggers on snare hits, it will also trigger on kick hits and loud cymbal hits.
Now you turn on the internal sidechain and dial in high and low cut so far that there's only a portion of the snare sound left, too high for kick, too low for cymbals. Often the internal sidechain unit has a button that lets you hear the sidechained internal signal. That signal is not part of the mix, it's just there to trigger the compressor. It needs a bit of adjusting but you can get it to only react to snare hits. Yes, the compressor will turn down the whole drum pattern, but only in the very moment of the snare hit, so it will usually sound as if the snare is quieter.

I hope this helps. Feel free to ask questions since there are no stupid ones 🙂
Guido

[Malcolm MiddletonParticipant]

Many thanks, actually I wasn't too far from from the reality but you're right the second version should have a different name because it is confusing and completely different form version 1. Thank you. 😎

[Jeff WernerParticipant]

Oh yeah! Maybe with a diagram or flowchart of some kind. It is confusing, and the way things get implemented is not intuitive. I’d be curious also if there are any other common implementations of a sidechain other than squashing the compressor. Eg, not in a daw but IRL, I’ve seen a chorus or harmony/pitch vocal pedal thats set up so that a performer can plug in their guitar as what I guess might be called a sidechain so that the pedal can figure out what chord the guitar is playing and add a harmony voice or pitch correction to the vocal that would be compatible with the guitar chord. Has anyone encountered a decent daw plugin like this? Or is the real hardware better to use given the need to analyze everything quickly?

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