PreSonus Blog

Friday Tip: Smoother, Gentler Sidechain Gating

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.

  • Jeff Evans

    It is cool way to set a compressor for sure. What happens too when you get the nice entry and exit happening is that when remove the null, the compression will often become much more transparent in its operation and just sound better. It is often these very initial entry and exit points that will make bad compression sound more obvious. Once you smooth these things out that will often go away.

  • Anderton

    That’s a great tip, and one of which I was not aware. It makes a lot of sense!!

  • Jeff Evans

    This reminds me of a technique that you can use to improve how any compressor actually works. And great that you have brought this up.

    The technique involves inserting a compressor over a track or mix etc. Then leaving that compressor over that source, duplicate the source track and invert the polarity and as you have described here the sound of the source track will null out except when the compressor actually does its thing.

    Its under these conditions you will actually hear how compressor comes in and goes out. (note this is much harder to hear when the music is present!) If a compressor is set badly, it will jump or leap in and go away rather badly as well. Setting attack and release and another things on the compressor will often result in a much smoother and nicer come and go type thing.

    Then remove the null track and you will be good to go. This technique is being highlighted here and for another purpose which is also excellent. Thanks Craig for bringing this up.