What is side chain compression ？
Side chain compression is just a variation of well know compression effect.
The only difference between
side chain compression and an ordinary compression is that at any moment in time in side chain the compression is driven by external signal (control) volume and applied to target (destination) sound rather then by the volume of the original target signal itself.
By order words side-chaining uses the signal level of another input to control the compression level of the original signal.
For sidechains that key off of external inputs, when the external signal is stronger, the compressor acts more strongly to reduce output gain.
This small difference plays huge part. the side chain effect is used everywhere we one need to lower music/instrument level when other instrument is played. For example it is used to lower bass volume when kick drum hit to remove clashing frequencies and avoid uncontrolled boom or by disc jockeys to lower the music volume automatically when speaking; in this example, the DJ's microphone signal is converted to line level signal and routed to a stereo compressor's sidechain input. The music level is routed through the stereo compressor so that whenever the DJ speaks, the compressor reduces the volume of the music, a process called ducking.
Side chaining opens all sorts of possibilities. One can heavily EQ the control signal so only when selected frequencies appear in the control signal, compress kicks in. Such a compressor can be used as a de-esser, reducing the level of annoying vocal sibilance in the range of 6-9 kHz. It can be assembled from a standard compressor and an equalizer by feeding a 6-9 kHz-boosted copy of the original signal into the side-chain input of the compressor.
http://www.soundzone.info/content/what-side-chain-compression
How To Use Side Chain Compression
Sidechain Compression Tutorial, Sidechaining, SSS Side Chain Compressor. The whole french house scene is practically defined by a signature sound. While the music itself is very different, every track seems to have this really loud sound. Some DJ’s call it a “push, pull”, “breathing”, or “suction” sound. It isn’t just artistry that creates this signature sound, it’s a lot of studio magic. That magic has a name: Sidechaining. After reading this SonicTransfer.com tutorial, you’ll know exactly how to do it.
To follow this lesson you will need:
What Does Sidechaining Do?Sidechaining takes one sound and uses it to manipulate another sound. Most often you will see it on compressors, gates, limiters, and expanders. However, it can also be found on vocoders, synthesizers, and other effects. It is a really, really useful feature on compressors and gates because it allows you to place multiple instruments in the same frequency range without clashing. Or, more succinctly, it can make your mix sound really good.
This tutorial is going to demonstrate
ducking using a sidechaining compressor. Ducking is the technique used by french house producers to get their characteristic “pumping” sound. Here are two snippets from popular french house songs that make heavy use of ducking:
Listen to the horns in the Daft Punk sample. Notice how they become quiet when the kick drum plays? That’s
ducking. The horn volume is ducked to make room for the kick drum. Listen to the DJ Falcon sample. The vocal loop gets ducked for the kick drum in the exact same way.
Now go grab any french house record from the last eight years. Almost all of them do it.
How Does Sidechaining Work?Sidechaining really just means feeding sound into an effect that works on some other sound. But when most people talk about sidechaining, they are
really talking about using sidechain compressors and gates to produce ducking. That’s what you will do today. This tutorial will guide you through setting up a Side Chain Compressor.
So, what does a Side Chain Compressor actually
do anyway? It uses one of your audio tracks to control the volume of another audio track. To get a ducking sound, it will lower the volume of one of your audio tracks when the other gets loud. The screenshot below shows the volume of a synth pad before it is effected and after it is ducked to make room for a kick drum.
http://sonictransfer.com/side-chain-compression-tutorial.shtml