I’ve always been fascinated with using one instrument to modulate another—like using a vocoder on guitar or pads, but with drums as the modulator instead of voice. This kind of processing is a natural for dance music, and using a noise gate’s sidechain to gate one instrument with another (e.g., bass gated by kick drum) is a common technique.
However, the sound of gating has always seemed somewhat abrupt to me, regardless of how I tweaked a gate’s attack, decay, threshold, and range parameters. I wanted something that felt a little more natural, a little less electro, and gave more flexibility. The answer is a bit off the wall, but try it—or at least listen to the audio example.
Setup requires copying the track you want to modulate (the middle track below), and then using the Mixtool to flip the copy’s audio 180 degrees out of phase (i.e., enable Invert Phase). This causes the audio from the original track and its copy to cancel. Then, insert a compressor in the copy, and feed its sidechain with a send from the track doing the modulating. In this case, it’s the drum track at the top.
When the compressor kicks in, it reduces the gain of the audio that’s out of phase, thus reducing the amount of cancellation. However, as you’ll hear in the example, the gain changes don’t have the same character as gating.
You can also take this technique further with automation. The screen shot shows automation that’s adjusting the compressor’s threshold; the lower the threshold, the less cancellation. Raising the threshold determines when the “gating” effect occurs. Also, it’s worth experimenting with the Auto and Adaptive modes for Attack and Release, as well as leaving them both turned off and setting their parameters manually.
Using a compressor for “gating” allows for flexibility that eluded me when adjusting a standard noise gate. If you want super-tight rhythmic sync between two instruments, this is an unusual—but useful—alternative to sidechain-based gating.