My vocal recording workflow often involves having five or more channels with harmonies of the same part. They have to be pitch corrected and compressed independently and, since I greatly prefer to compress post-EQ, they must all be EQ'd independently too. This leads to a situation where I have five (or often more) identical channel strips with redundant effect definitions (but not redundant DSP) on each one.

This means that to audition an effect change, I must change one and then duplicate it across all other vocal channels, which often leads to a reluctant approach to refining the effects on what tend to be the most important parts of a track.

What I would like is a way to effectively alias effects such that I can change one defining effect parameter and have it propagate to all the other channels automatically. Is this possible? If so, how?

Redundant effect definitions in five vocal channel strips

  • I'm not sure I completely understand your question. Have you tried running individual channels for the FX that need to be unique, but then running them all into a common bus where the common FX live? If that doesn't work for you, then you may need to dive into the Logic Environment. Commented Oct 28, 2012 at 15:48
  • I can't use a bus for this; the effects need to be different instances of the same effect. A compressor on a combined bus would, for example, reduce the level of all tracks if one of them spiked. Pitch correction on a combined bus wouldn't work at all, but all pitch correction instances on all channels should be configured identically. I do typically put effects on the master vocal bus, but only ones that wouldn't work better on each individual channel.
    – Iain Dawson
    Commented Oct 28, 2012 at 15:54
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    In that case, the Logic Environment is probably your best bet. You will have to do some digging to figure out how to address AU plugins though. Commented Oct 28, 2012 at 16:20
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    @IainDawson I think you may be over thinking what happens if you move the compressor to the bus. In this situation I put the EQ and the compression on the bus everytime. If a vocal has a peak that is so bad that it cauces the problem you are concerned about (unlikely) than you should automated down the level of that track (which will work better than letting a compressor do it for you.) Compressing the bus can help make the harmony's sound more cohesive as it will give them all a more consistant dynamic.
    – JPollock
    Commented Oct 29, 2012 at 0:05
  • Doing vocals, I'll typically compress on the bus as well as per-channel, but it's not just vocals that have me running into this limitation. If, for example, you've got several harmonising solo DI guitar parts with a ridiculous chain of pedal/amp simulation, it sucks to have to maintain duplicate signal chains independently.
    – Iain Dawson
    Commented Oct 29, 2012 at 0:25

4 Answers 4


If you have a hardware midi controller with dials or faders you could assign the midi CC of one of them to the parameters you wish to change on each instance and set all tracks to armed. This would change them all instead of just one in the same way that you can play multiple instruments at once.

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    That's a neat idea. In theory, you could set up a virtual motorised MIDI device and that would solve this whole thing. It wouldn't be saved in the session file and you'd need one for every device you want to alias to, but it'd work better than anything else that's been proposed. Does such a thing exist, or am I gonna have to write it?
    – Iain Dawson
    Commented Feb 26, 2013 at 19:31
  • Im not sure of one off hand but it would seem like something that surely must exist. Its simple enough to do with hardware so really all you need is something that would send similar midi CC messages to logic. You could send on the internal mac bus easily enough. If you do go down the writing it yourself route, writing a controller in java to send midi messages is relatively simple (Ages ago I did something similar that sent out midi messages in response to hand gesture control commands).
    – Philip Graham
    Commented Feb 28, 2013 at 10:04

I often encounter this situation. In fact this is how I bumped onto your question since I again have that situation (some 10+ back vocals that all need to be pitch shifted -100 cents).

If you have the option of using a project template the best thing I found out to work is to create environment patching with a single control for a parameter across multiple tracks.

It is not that hard to do it and Logic is great for this. But it takes some time so it only makes sense if you have either really 10+ channels or can have a template with prebuilt environment for multiple similar channels.

Workflow is like this:

1) Open MIDI Environment

2) New Monitor

3) Tie any of the channels to the Monitor (little triangle on the top right of channel drag to similar on Monitor)

4) Move the control you would like to use on multiple channels (for me it is pitch)

5) Check the value on the Monitor. It will be something like F2 1 63

In fact it is a MIDI msg. First parameter is used to map a plug in on the channel. 2nd is the parameter of the plugin you are changing. 3rd is the value.

6) New Fader (type you like, I use Knob for this because thats how it is in the plugin, a rotary knob)

7) In the left side inspector, set

Output: Fader

Channel: First parameter (what is right after letter F in monitor)

Parameter below Channel: the 2nd number

Leave rest as is.

Logic Environment Fader settings for Monitor Data F2 1 63

8) Now connect Fader (small triangle) to a channel and you will be able to control the parameter with the Fader.

9) Connect Fader to all chanels and.... Voila! That's it.

Good thing is that it works real time so you can make a lot of crazy stuff with that also :)

Logic Environment for multiple channel plugin parameter control


I came up with a bad, inextensible and mix-compromising solution: make a Surround bus and use multi-mono effects. This makes panning awkward/impossible, puts all effects post-fader (unless you're willing to put up with using the multi-channel gain plugin as a mixer) and you're limited to five channels at a time, so I'm not sure I'd consider it an improvement.

Five channels routed to a 7-channel surround aux with multi-mono effects


Have i missed something, isn't the answer simply "grouping" the tracks together? Then as you control one parameter it controls the same parameter across all tracks you included in the group? Select the tracks on the mixer, right click (two finger click, ctrl + click on mac) and hit "Group". Then when you edit one parameter it'll change on all of the tracks in the group.

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