Sidechain compression is something I feel that everyone approaches a bit differently. I know so many producers who insist on having it done a certain way – from specific settings (RMS only, cranked ratio, minimum attack etc.) to certain plugins (like LFO Tool, ProC or Volume Shaper), and at the end of the day there’s no true “right” way of doing it. Though I too have my go-to settings for sidechain, I recently stumbled across a technique that I think is overlooked by a lot of people: sidechaining only specific frequencies in your sound. By doing this, you can create space in the low end of your mix very easily without affecting the top end dynamics. Many third party plugins have the ability to achieve this effect, but fortunately it’s pretty easy to do right in Ableton as well.
The rack I’m about to explain can be downloaded for free here
The effect you’re gonna want to reach for is multiband dynamics. Once you’ve got it open, go ahead and open up the sidechain panel by hitting the arrow next to the title. Engage it, and note the input section. I am going to select a channel named “TRIGGER” which is a kick loop which I’ll use to test that the effect is working.
I’m assuming you’re going to be sidechaining the low frequencies in your sound, so we’ll be focusing exclusively on the bottom band. If you want to experiment with sidechaining the upper frequencies, the process is exactly the same, you just have to use one of the other bands. For me, this interface gets a little counterintuitive for what we’re trying to do, so to make everything a bit easier to manage, I’m going to map everything we are using to its own unique macro knob.
There are 5 main settings we want to be looking at here: attack, release, ratio, threshold, and frequency.
The first 4 settings are going to live under the ’T’ and ‘A’ sections. You can find these in the bottom right hand of the effect where you see ‘TBA’. ’T’ stands for “time” which effects the attack and release times of the compressor. Multiband dynamics defaults to this panel, so we can go ahead and map out the attack and release to separate macros.
Next let’s switch over to the ‘A’ panel. ‘A’ stands for “above”, which refers to the ratio and threshold of the downwards compressors.We’re just going to do the exact same thing here and map those values to their own macros. Once those are locked in, the only thing left to map is the frequency of the low band. Go ahead and give that guy its own knob as well.
Sweet so this thing is pretty much good to go at this point! The only issue is the ratio knob – right now if we increase the value of the macro, the ratio actually decreases. It can decrease to a decimal, creating upwards compression (which is the exact opposite of what we want). To fix this, simply open up the mapping section, right click and invert the ratio macro, then set the minimum value to 1 : 1.00 (just click where you enter the value and hit 1).
I went ahead and set all of my macros to more realistic settings so that the rack is easier to use in a session. In addition, I mapped the compressor style (displays as RMS at the bottom of the inputs) to another new macro. I also just renamed all the knobs to be more straight forward.
Now we have a fully functional frequency-specific sidechain compressor! Go ahead and play with the frequency knob after setting up a source for the sidechain and throwing some content on your channel. I like to loop just a single kick drum for the source and then play a synth tone of several octaves. Notice how the lows get smoothly scooped out of the mix. I love the way it can tightly pack together different elements without creating too much pumping. I find myself using it on reverbed pads or vocals to allow them to reach down into the lower end of the mix without clashing with kicks or impacts. It can also be useful for sidechaining basses – it’s even interesting to use on top of standard sidechain in order to push a bit more room into the ultra-lows.
Experiment with this thing, and feel free to leave your thoughts in the comments below – cheers!