Multiband Sidechain Compression
Although side-chain compression is the go to for the classic “pumping” effect, its main purpose is to help mix two elements that have clashing frequencies, the most common example being the kick and the bass. There may be situations where we want to side-chain only specific frequency bands, helping to clean up a mix without pushing a specific sound out of the way. For example, we may want the low end of our bass to duck when the kick hits, while the upper harmonics of the bass stay unaffected (i.e. not side-chained).
We can use multiband side-chain compression in any DAW. One way to do this is to split up a sound into multiple frequency bands and side-chain only the desired band.
TrackSpacer by Wavesfactory is a dedicated multiband side-chain plugin. It listens to the EQ spectrum of an incoming signal and applies a reverse EQ curve to the track. Below is an example of this in action, where the blue EQ curve represents the incoming signal of a kick, and the white curve is the EQ curve applied to the output bass track.