Bass sidechaining is one of the most ubiquitous techniques in dance music. Whatever kind of bass part your track features, you can use sidechaining to add bounce and pump, duck it to make way for other sounds, or simply pull your bass and kick in tightly together.
The basic concept is simple: sidechaining uses an external source to modulate a dynamic effect (normally a compressor) so that it is effecting the audio channel to which it is applied, but is not controlled by or following it. Rather, it uses another audio source, known as a sidechain key, to control when and how much it compresses.
In the case of bass, sidechaining is nearly always done using a kick drum to control the compressor, ducking the bass for the duration of the kick sound to ensure that the kick punches through. This often generates an audible pumping effect in the bass.
The results can vary according to the plug-ins you use, so the key to good sidechaining is finding a compressor that suits your needs - whether you’re after punch, heavy pumping or smoother sidechaining, which can be useful for real kits and electric bass guitar lines.
Once you’ve had a go at our technique that’s outlined over the next few pages, there are a number of additional things worth trying out with your sidechained bass parts. One is some firm limiting on the bassline after the sidechain compressor.
This is regularly overlooked, as common sense would seem to indicate that the limiting would undo the pumping effect - in practice, however, it often works to fatten the sound while retaining some of the pumping effect.
Another important thing to note is that compressors can change the overall level of the audio signal. This means that if your kick drum stops in the arrangement the level will leap up, as the compressor will no longer be getting any signal and will thus stop compressing.
You can balance this beforehand with the compressor’s gain so that the signal is about the same level with and without a sidechain source, or you can create a kick drum playing all through your track that is not set to any output and so is unheard.
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