I'm just getting my head around sidechaining, and I'm not sure if this is a sidechain thing or something else. I have a synth drone that goes on and is somewhat dynamic, with some louder and quiet parts. I'd like to have it so when it reaches a certain volume, it brings in a sub-bass tone that I have recorded on another track and then takes it out once it gets below that same threshold, with a gentle attack and release. How do I do something like this?

 

you would have the drone track actually playing the entire time. you would add a noise gate plugin on the drone, which would be reacting to the other channel. this is actually a very common trick in electronic music using a gate plugin and a test oscillator to add sub bass to a kick drum.

when the volume of the one channel crosses the threshold, the gate opens and allows the drone channel to be audible also. it sounds like you want it to ramp up/down in amplitude, and i have never tried that part lol. I would just draw in some quick volume automation on the drone after you get the gate part done. the sidechain will be the gate reacting to the amplitude of the other non-drone track.

set this trick up and do it anyway. it's very useful and will be a good use example of sidechaining to try out. pretty simple. it's a great way to add to a dead kick every time it plays when you are mixing.

 

Last edited: Dec 28, 2023

you grab the track with the synth drone (let's call it A), create a send to the track with the sub-bass tone (B). then in the I/O routing window you will see something like this:



that 1/2 is input 1 and 2 of the track you're sending it to (B), you have to change that 1/2 to the sidechain inputs on the receiving channel which are usually 3/4 (click the 1/2, go to new channels on receiving track, 3/4). If you don't, you'll get the audio of the track A on top of the audio of track B at track B's output.

Then you just have to insert the plugin on track B after the sub-bass tone (for what you want to do, i think you want a gate), set it to be triggered by external sidechain, tweak it as you please, and that's it.

Keep in mind that not all plugins can work with external sidechain. If you go to the plugin window of the plugin on track B and click here (marked in red)...


You can see in the emerging window that this plugin in particular does have a route to the external sidechain (marked in green), and then the input 3/4 (yellow) which are receiving from the send we made on track A, are following the path indicated by the blue arrows. If the plugin doesn't have external sidechain inputs, 3/4 get thrown into the stereo L and R, which is bad.

TL;DR: make a send, send to tracks 3/4 of the receiving track, put a gate on the sub bass track and set it to external sidechain, and it'll probably work.

 

Last edited: Dec 28, 2023

that is really complicated looking that way. this trick definitely works, because i do it all the time in Logic to add to my kicks. but I use the Logic stock Gate plugin and Test Oscillator plugins. It's very fast because most of the Logic stock plugins can accept external sidechain signal. What most of them do not have like other plugins though, is usually Sidechain Gain and filter.

What that trick does show someone though who wants to try new sidechain tricks, is that a compressor is not the only answer. This one is basically an inverse to allow sound in, rather than trying to smash it down. You could really screw around with the compressor settings trying to get this effect to work, and you might even get it close. But it works better to use a gate allowing signal, rather than a compressor to reduce it.

For this drone idea, I wouldn't want to link it this way in most cases. I would probably just set Shaperbox to a greater number of bars and draw an envelope. Or something like that ;)

 

It could work with ReaGate on Sub-Bass with Detector input = Auxiliary Inputs (so 3/4).
As a rough starting point, Attack ~ 200ms, Release ~ 1000ms, Hysteresis -6dB. Then you'll need to set the threshold so high that the Sub-Bass is gated as long as the source (Drone) is low and crossed when the source is loud.

 

for more general info on side-chaining in reaper a pretty great video Compression and Gating 3 ways :

 

Excellent, thank you.

 

As of Reaper 7, has improvements in sidechaining.