Side Chain Compression in Logic Pro

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Tutorial / HowTo / LogicPro / Basics

This is a description of how I use side chain compression in Logic Pro 8.
The concept is very similar in most other sequencers.

The most common use for side chain compression is to make more room for your instruments in the mix by letting a key input signal trigger a compresssor or limiter.

I use side chain compression mostly on bass/subbass tracks triggered by a kickdrum (commonly called kick/bass compression or bassducking) to either make that well-known “pumping effect” or just mix the bass in louder and get some extra dB in the mix.

In most cases I use two kickdrum tracks, one “main” kickdrum, and a second kickdrum (on which I can use different EQ and envelope settings) to trigger the bass compressor. Using that extra kick for the bass compression instead of the main kick keeps the compression on the bass line if the main kick isn’t playing, say in the intro, break, etc.

LogicPro Trackview
The basic tutorial:

  • 1. Create a new audio or instrument track for your main kickdrum. (Kick1)
  • 2. Create a second track for a kickdrum which is going to control the bass compressor (Kick2 (SC)). You can simply duplicate the first track.

LogicPro Mixer

  • 3. Create a Bus channel (called “SC input” in this screenshot) and set the volume of this Bus channel to “- infinite dB”, the lowest volume possible. (don’t mute the track!)
  • In this example I used Bus11 (as I most often use Bus 1 to 10 for aux send/return Effects, and the rest for sub-mixes and side chain voodoo, etc.)
  • 4. Set the output channel of your second kick (Kick2 (SC)) to the Bus channel you just created.
  • 5. Create the bass line track.
  • 6. Insert a compressor at the very end of the chain on the bass line track.
  • If you want some additional effects to your bass sound, add them before you insert the side chain compressor. You could – and probably should – use some EQs on your bass.

LogicPro Compressor-PlugIn
Compressor settings

  • 6.1. Set the compressor´s external sidechain input to Bus 11. You set the external sidechain input in the upper right corner.
  • 6.2. Set the attack between 0 to 5ms to compress the bass immediately/fast.
  • 6.3. Set the knee to hard (0.0) to trigger the peak of the signal.
  • 6.4. Set the ratio between 10 and 40, depending on how much compression you want. – The more ratio the more pump in the bass line, which might be just what you want.
  • 6.5. Set the release time depending on how long you want the bass to be compressed, usually quite short, e.g. 20 – 50 ms.
  • 6.6. Set the threshold level between 5 and 20, depending on how much compression you want.
  • 6.7. Try different settings for Circuite Type/mode and attack/release time to fine tune the pumping effect/compression.

Here are some demos for comparison:

For now, I’ll leave you to experiment.

Try different compressor settings and/or input signals and different envelope settings of your triggering Kickdrum.
You could also experiment using side chain compression on other tracks, eg. on strings/pads, vocals or a submix.

I hope this helps.

Feel free to contact me with any questions or comments. I will try to respond to all comments as soon as I am able to.

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24 responses to “Side Chain Compression in Logic Pro”

  1. dan_djorgi says:

    Feel free to contact me with any questions or comments.
    Happy Sidechaining! 😉

  2. Silv says:

    idiot proof explaination.

    thank you!

  3. matev says:

    Very useful, thanks.

  4. Dih says:

    very thnks bro

  5. Ric says:

    Great tutorial, pumping demystified. Thanks so much.

  6. TehSlav says:

    Good tutorial. Thanks!

  7. Jacob Gude says:

    NIce!! Gave me a better understanding of using SideChain

  8. blak ghost says:

    thank you!!! Very simple precise instructions….THANK YOU!!

  9. soco says:

    nice thanks

  10. Tee Dubs says:

    Hi great tutorial thanks.. I want to bounce my sub track with the side chain compression I've applied, how do I do this and not record the kick track also? I mute/ turn down the kick track and then obvs loose the pumping effect.. I'm sure this is easy but I'm stumped..

    Help!

    T

    • dan_djorgi says:

      Hi!

      Have you used two kickdrums like I did in my tutorial? (One "turned down" for the sidechain input and one "main" you use in the mix)

      If so, you probably just muted the wrong kickdrum.

      Let me know if this solves the problem.

      Cheers,
      Dan

  11. Tee Dubs says:

    I did but couldn't get it to work.. In the end I set the output of the kick drum to "no output" and bounced the sub bass which worked a treat.

    Thanks for getting back to me tho and keep up the helpful work!

    Cheers,
    Tom

    • dan_djorgi says:

      Hey Tom!

      That's strange. What happens when you put your sub track and the track triggering the related compressor on solo?

      Even though you found already a way to bounce your bass track, here's a link to the original Logic Pro-Project File I used in the Tutorial, so you can take a closer look at my settings:
      http://goo.gl/nrJIO

      I'm glad you found the tutorial helpful – Thanks for the kind words Tom and keep that bass pumping,
      Cheers,
      Dan

  12. Greg McLaren says:

    Incredibly helpful! Even better than a youtube video

  13. Arjun says:

    Thiss stuff is good….thanks Dan

  14. Morgan says:

    Terrific explanation and I have subscribed to your blog. 🙂 Thank you friend! 🙂

  15. danwpc says:

    Hey, Dan, this worked nicely. Question: Why don't you just feed the first kick straight into the compressor side chain? How is that different from creating a bus, feeding it with a second kick and then feeding that into the bass compressor? That's seems unnecessarily complicated, but I'm sure I'm missing something here… (new to side chaining). Is it an issue of how hard the kick is pushing the compressor? Isn't that controlled sufficiently by the compressor ratio?

    • dan_djorgi says:

      Hey danwpc!

      You can, of course, use the first kick only to trigger the compressor of the bass-loop, but using a 2nd, dedicated (and continuous) kick on a bus-channel has a couple benefits.

      First of all, one could use that single Side-Chain-Input-BUS to trigger multiple compressors on multiple (bus/sub-)channels. For example, I usually route multiple channels to sub-channels (basses, strings/pads, percussions, etc.) and use the same kick drum ("SC input") to trigger a compressor on each of those sub-channels.
      In addition, using a 2nd (continuous) kick drum for SC-input, keeps the compressor active (pumping, in this case) even if the main kick drum is muted/not triggered – like in breaks/intros/outros/etc. – but you still want the compression/pumping on your other tracks/channels.

      I tried to outline this in the intro of this tutorial: "Using that extra kick for the bass compression instead of the main kick keeps the compression on the bass line if the main kick isn’t playing, say in the intro, break, etc."

      I hope this makes any sense! 🙂
      Drop me a line if you have any more questions.

      Cheers and happy sidechaining,
      Dan

  16. danwpc says:

    Thanks for your response, Dan. What I love most is that it took you only a few hours to respond to a comment on a post you created 5 years ago! Long live the interwebs.

    • dan_djorgi says:

      Well, as long as this tutorial is helpful for anybody – even 5 years after publishing – I'll keep on answering questions! 🙂

      I hope my reply answered your questions, btw?
      In case you have any more questions, drop me a line!

      Thanks for your comments, danwpc,

      Cheers,
      Dan

      P.S.: You can also download the template (logic project) I made for this tutorial. (I shared a link in one of the previous comments). So you can take a closer look at my settings or use it as a starting point for your own productions.

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