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Sidechain with Aux sends only (less latency)

When we use Insert Sends then we get a latency penalty of one jackd period compared to an Aux send. This becomes audible depending on your jack period size.

There is a way to use Sidechains with Aux sends only.

Example: We want to use Calf or LSP side chain compressor. The snare drum shall "duck" the bass to make the snare snappier.

Snare track (with stereo instrument plugin) -> 4 channel output bus "snare" -> 2 channel master bus

Bass track (with stereo instrument plugin) -> 4 channel output bus "bass" -> 2 channel master bus

We put the side chain compressor into the output bus "bass". The plugin uses channel 1+2 for the signal to be ducked and channel 3+4 für the side chain.

So the bass audio will go to 1+2, that's what we want.

We cannot simply use an Aux send in the snare track to the bass bus because the snare signal would end in 1+2 as well. So we have to move the snare signal to 3+4, e.g with Carla patchbay 16 chan, then use an Aux send to the bass bus, then move 3+4 back to 1+2 with another Carla patchbay 16 chan.

This way we have the snare on 3+4 for the Aux send and on 1+2 for sending the signal to the snare bus.

Works for me.

Make sure that all other tracks don't go directly to the master bus but to a staging bus that goes to the master bus. Then you have the same latency because the signal always goes from a track to a bus that goes to the master bus.

rncbc's picture


please consider contributing to the wiki--and ultimately to the manual--please?

this knowledge is way tooo valuable and precious for not being in the official wiki/manual, or else in complement to the sidechain how-to...


I'd like to write 2 little instructions:

  1. Get your latency right (number of "hops")
  2. Sidechaining with Aux Sends

Maybe the wiki is a good start. How can I get a userid?

rncbc's picture


you already have a user added you to the board of wiki editors.

you may start anytime now


I added "How To - Equal Latency for Tracks and Buses". Please check if it's ok. Then I'd write the Sidechain with Aux Sends How To.

rncbc's picture

looks good!

missing some credits (to you)?

I'm fine with it.

Hi bluebell and Rui.
It's a good solution for latency. Thanks for sharing.

(On the way, I reviewed "How To - Sidechain Workflow" and it still has small errors. I'm going to correct them.)

I added "Alternative Sidechain Workflow with Aux Sends" to the wiki.

rncbc's picture


please tell when ready and done for a new manuals&howtos edition!


rncbc's picture

the latest incarnation (etymological akin to current not-so-holy-days of carnival) may be assessed right here:

  • Manual & How To's: [epub] [pdf] [html]
  • cheers

    Meanwhile... I modified a large part of the illustrations to make them more precise and understandable, and I didn't arrive in time. In fact, at the precise moment it was generated, I deleted the "switch plugin" illustration to upload the new version, and it does not appear in the manual. It is not important, it is understood with the description of the text.

    This can wait until the next time a new tutorial needs to be updated. :)

    Now it is updated.

    Looks good. Even my latest update from today is contained.

    You forgot to update

    How To 6 and 7 are missing.

    rncbc's picture

    no I didn't forgot

    I'm waiting for your "done" message!

    is it?


    rncbc's picture

    done. it is now:

  • Manual & How To's: [epub] [pdf] [html]
  • thanks

    I am sorry but I added an important update. With x42 Matrix Mixer there is no noise when stopping the playhead.

    rncbc's picture

    no worries

    new edition coming up... now.


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