How To Route Audio In Logic Pro | Using Sends And Buses

Nov 02, 2023
How To Route Audio In Logic Pro


Digital audio workstations (DAWs) provide myriad tricks and techniques for producers to work more efficiently on their musical projects. One of the critical methods for saving time, energy, and computer resources when working on large projects in Logic Pro is using buses to route individual channel strips.

In this post, I will guide you through everything you need to know about using buses and auxiliary channels in Logic Pro. But before that, let’s see what makes audio routing so important.



What Is Audio Routing

By default, Logic sends all of your audio and software instrument tracks to the Stereo Out master track. If you open the mixer on one of your Logic sessions, you’ll notice that each channel strip comes with an individual volume fader, pan knob, and slots for adding audio effects.

Your main stereo out channel carries all the signals out to your output device. Muting/unmuting and adding plugins on this channel will affect all the individual audio signals in your session. You can press “X” on your keyboard to open the mixer window. Alternatively, you can press “COMMAND + 2” to open the mixer on a separate window.



As seen in the screenshot above, I have one software instrument track, two audio tracks, a stereo out, and a master channel strip. If we consider the stereo out as the final destination for our tracks, routing audio means adding stations for specific tracks to go through before they reach the end of the line.

Why is that important? Adding stations mid-way allows you to treat groups of signals as one. Say you have certain audio effects you want to use on multiple tracks, and, for the sake of consistency, you want the plugin to be identical to create a homogeneous atmosphere across your project. Instead of adding multiple copies of the same plugin on different channels, you can create a new station, run your plugin there, and send your audio channels to it before they reach Stereo Out.

Not only does this save you significant time, but it also is a critical technique for managing CPU power in Logic.

Typically, you’d want to use buses and sends for reverb and delay effects. Other candidates for this style of audio processing are parallel compression, modulation effects, and essentially any plugin you want to use on multiple tracks with identical parameters. In a YouTube video tutorial, I explain how to bus out reverb and delay in Logic Pro.


How To Use Buses To Route Audio

Using buses (or auxiliary channels) allows you to route audio signals in Logic. You can access buses either from the Inspector menu or the mixer window. Let’s take a look at the mixer:


  •  Click on the “Sends” slot to open the bus menu.
  •  Select one of the empty buses to route your track’s signals.



Once you add a new bus track, you’ll see it in your mixer window as “Aux 1.” You’ll also see a small volume knob next to each send on your original track. The knob controls how much of your track’s signal goes through the bus.



You can rename your bus track by double-clicking on its name from the bottom section of the mixer window.

Now, you can treat your bus as a regular track by adding effects such as reverb and delay. As an example, I’ll add Logic’s stock ChromaVerb plugin to create a lush, atmospheric hall reverb for my tracks. I also changed the bus’ name to “Big Reverb” to keep things nice and tidy.



Typically, you’d want to set your Dry channel to 0% and max out your Wet channel since you already have a dry signal coming through your original track.

Now, you can send other tracks through the same bus to add the same effect.



Now, you have multiple tracks going through the same reverb effect without adding the plugin on every track.

If I solo this “Big Reverb” bus track, I can hear all the signals coming in, going through the reverb, and coming out. Since the dry signal on my reverb is set to 0%, I will only hear the effects and not the original signal.



Panning Buses In Logic

Logic offers three panning settings for buses: Post Pan, Post Fader, and Pre Fader.

Post Pan: sends your signal after the fader and pan knob; the send signal is affected both by adjustments to the channel strip volume fader and pan adjustments. So, if your audio signals cover the left side of the stereo field, Logic will also pan the signals coming out of the bus to the left.

Post Fader: sends your signals after the volume fader but before the pan knob. This means that volume adjustments will affect what goes through the bus, but the pan adjustments don’t.

Pre Fader: the signal is affected neither by volume fader adjustments nor by changes you apply to the pan knob.

Each of these is applicable based on your preference and the creative goals you have in mind. You can choose one by clicking on clicking a bus and opening the pop-up menu.



Moreover, you can adjust panning and volume on a bus to affect all the signals that are coming through. I suggest keeping the volume fader on your bus track as it is and changing the send volume individually for each track.




Final Thoughts On Using Sends And Buses To Route Audio In Logic

Knowing how to use buses is a vital step towards taking your music production skills to the next level and streamlining your workflow. Not only does it save you a ton of time, but you can also avoid system overloads that might lead to losing your progress. Moreover, there are other measures you can take to prevent having to force quit Logic and risking data loss.

For more lessons regarding songwriting, music production, mixing, and mastering, check out my Free 6 Pillars To Learn Logic Pro Faster guidebook.

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