Building a Sidechaining Compressor

I’m still a bit new with the ER-301, about two months, but it’s done a good job at reducing my GAS surrounding getting new modules. One thing I know the ER-301 can probably do, but can’t figure out, is building a side-chaining compressor. I’d think that one would modify the gain of a VCA processing one input with the signal coming from another. I’ve tried using the envelope follower and other things, but I’m getting bleed of the kick signal coming through. Any tips on how to build a Side-chaining unit?

Do you want a full compressor or something you can key to create ducking style effects?

If it’s the latter:

-place a VCA after the signal you want to duck.

-Set the VCA to open (bias 1).

-Within the VCA, select your source audio - IE: the ‘key’. a kick drum from another output or external signal etc

-In this same chain, add a limited to up the gain, then rectifier - using positive half and then add an envelope follower after it. Set a small attack such as 10ms, and a long release such as 150-300ms depending on the material

-Tweak the VCA gain to taste, -1, -2 etc.

If your source sound is a pad and you feed the VCA input a kick… the pad will pump and you wont hear any of the source material until you decide to mix it in.


Thanks Neil,

succinct descriptions of building blocks such as these incredibly useful for me.

Thanks Neil. It’s pretty darn close but I’m getting some AM modulation from the envelope follower. I’m still a few revisions back, so there may be some tweaks on the follower, or even a slew unit that I don’t have yet.

You might want to try adding a few in series with smaller values to smooth it out.

I did pretty much what Neil suggests there, but instead of a kick drum I chose the audio itself as the ‘key’, which essentially provides you with a very basic compression of the signal. I think it’s important here to tweak the values and experiment to not get strange artifacts, but slew and envelope followers sound like your friends.

coming to think of it, I was quite fond of the option of negative attack times of a few ms on a software compressor, and I’m realizing this can be achieved by delaying the audio to be compressed slightly. this would eliminate the clicking sometimes associated with hard compression and fast attacks on snappy drums that I think I got previously. feel free to set me straight if this is not feasible tho.

compression + ducking? combine the two methods above. while I’m sure it’s possible to just modulate the **** out of a single vca, I see no reason since it’s simpler and easier to manage by just using 2 in series for the separate tasks.