Sidechaining has been around for years; this is the process of using one signal to control another. A couple classic examples are using a kick drum to gate a bass part, or doing de-essing - isolating the high sibilant frequencies from a vocal, and using those to trigger compression so that the sibilants come down in volume.
But in the digital age, we can do a lot more with sidechaining. One of the most popular applications is with dance music, where sidechaining can create the "heavy pumping" electronica drum sound used by artists like Eric Prydz and others.
We'll describe how to do this with Cakewalk Sonar, although the same principle applies to other programs that allow for sidechaining. Sonar allows sidechaining for several effects, including compression, so that one instrument can control the compression characteristics of another instrument. This offers a variety of effects, including a "pumping" drum sound for multitracked drum parts; we'll do that by setting up the snare to control compression for all drum tracks.
Fig. 1: You'll need a drum submix bus to create an overall drum sound.
The first step is to create a drum submix bus, and send the drum tracks to it (Fig. 1). We need this submix so the entire drum track can be processed by the sidechained compressor. To create the submix bus, right-click in an empty space in the bus pane and select "Insert Stereo Bus." To create a send in track view, right-click in a blank space in the track title bar and select "Insert Send." From the menu that appears, select the send destination. Make sure you feed the bus pre-fader, and turn the individual drum channel faders down so that only the bus contributes the drum sound to the master.
Fig. 2: Assign the Drum Submix out to your main stereo output.
You'll also want to assign the Drum Submix output to your main stereo out (master) bus (Fig. 2).
Fig. 3: The Sonitus:Compressor comes with Sonar, and can do sidechaining.
Next up, insert the Sonitus:Compressor (which allows for sidechaining) in the Drum Submix bus's effects bin (Fig. 3). This will allow for processing the entire drum track.
Fig. 4: Use lots of compression!
Now it's time to program the compressor for really heavy compression - e.g., threshold below -20 and a ratio higher than 10:1. This can definitely add some "squash" as needed; we won't be adding it all the time, but only when the snare hits. Note that a softer knee compression curve often sounds better than a hard knee for this particular application.
Fig. 5: Assigning a bus to the compressor's sidechain input.
We still need to generate a signal to drive the compressor's sidechain input, which in this case would be the snare so that the drums "pump" whenever the snare hits. The simplest way is to create another stereo bus, then assign its output to the sidechain input. Now all we have to do is make sure the snare drum feeds this bus.
Fig. 6: Use the snare signal to provide the output to the sidechain.
Create a second pre-fader send in the snare track, and assign its out to the bus feeding the sidechain input.
Fig. 7: We're almost there - it's time to adjust the compressor.
To adjust the compressor, start with the compression attack time set to 0 ms; the drum sound will essentially disappear when the snare hits because the gain is being reduced so much. Gradually increase the attack time to let through more of the initial snare hit, and add a fair amount of release (250-500 ms) to increase the apparent amount of pumping.
And there you have it - the pumping drum sound. May it go over well on the dance floor!
Originally published by Harmony Central. Reprinted with permission.