Bussing in Logic Pro X is a super power that often gets overlooked by Logic users.
For example, the other day I was talking to a friend. He was working on a project and wanted to geek out about Logic.
He whipped his Macbook around to show me what he was working on. And the first thing I noticed was that he had Space Designer on every single track.
As he spoke, I couldn’t even focus on what he was saying. All I could do was think about how much CPU he was wasting by not using busses.
Busses are your shortcut to:
- Saving CPU,
- Grouping tracks,
- Using effects, and
- Sending audio wherever you need it to go
And by not bussing in Logic, you’re screaming to the world:
Don’t get caught being a basic Logic user. Let’s upgrade your workflow with bussing.
Auxes, Busses, and Sends – Oh My!
Step one when it comes to bussing in Logic is to first figure out what the heck all the weird words actually mean!
If bussing intimidates you, I bet it’s because of the words we use. Such as:
When you have 3 words that kinda mean the same thing, but aren’t the same – it gets confusing.
Let’s define each word so you can get past thinking about them:
What is a Bus?
Before we go any further, what the heck is a bus?!
Imagine the plumbing in your house. Most likely you have running water in your kitchen and bathroom.
But that water doesn’t just appear. It needs a way to get into your house.
Modern plumbing uses pipes to get water into your home.
And busses are pipes for audio.
When you hit play in Logic, its like you turned on the faucet. That audio only goes in one direction – to the Stereo Output.
But say you want your audio to go somewhere else, like a reverb. How do you get it to that reverb?
You got it – with a bus.
Busses allow you to create pipes between tracks. You can combine tracks, send them to effects, or send them just about anywhere you need them.
What is a Send?
If you take a look at the Mixer Strips in Logic, there are a couple of empty fields with some empty looking circles.
These fields are your Sends.
A send is like the on-ramp for the highway.
Your audio hops onto the on-ramp, and slides its way down your bus to it’s intended destination…
The Aux Channel.
What is an Aux?
Auxes are just like any other channel in your project. The difference though is audio doesn’t live on your Aux, like it does on other tracks.
It’s sent to your Aux.
The Aux is like the faucet your water spits out of in your kitchen.
So if you put it all together the flow looks like this:
Audio Track -> Send -> Bus -> Aux
Controlling the Flow of Sound
Now you know what the heck these words mean. The next step is putting the pieces together.
When you click on one of those empty fields, a menu will pop up for creating a send:
The next step is to pick which Bus or pipe you want to send your audio through.
As of Logic 10.3, you have 256 to choose from.
What’s awesome is once you pick your bus, Logic automatically creates an Aux for you:
Now your audio has a place to go!
Throw your favorite reverb on that Aux, and you can send as many tracks as you want to it.
But then you need to decide how much audio you want to send to that Aux.
Turning on the Faucet
Your Send is the on-ramp. But just like your kitchen faucet, you need some way to control how much audio comes out.
Thankfully, you can choose how much audio is sent to your Aux with the circular volume knob:
You probably don’t want your track drenched in reverb. Or maybe you do!
The Send Volume is your way to decide. Bump it up or down to fine-tune the volume.
But you can also send it full-blast to your Aux, and just turn the Aux volume up or down.
The audio plumbing world is yours to decide 😉
Post Pan, Post Fader, or Pre Fader?
If things weren’t hazy enough, there’s another set of words to wrap your brain around.
When you dig into the Send menu, you may notice another set of foreign looking phrases:
- Post Pan
- Post Fader
- Pre Fader
All these phrases are asking you one thing – when do you want your audio sent to your Aux?
That might seem like a weird question, but it matters:
Post Pan means that your audio is sent to your Aux after your:
- Channel Fader
This is Logic’s default, and for good reason.
Usually when you pan your audio, you’d like your Reverb or Delay to do so as well.
So Post Pan makes sure that your track’s panning is sent to your Aux.
And if you decide to turn down your audio track with the fader, wouldn’t you like the reverb to turn down too?
Post Pan covers all your bases so that Reverb plays nice.
Post Fader sends your audio after your Channel Fader, but before your panning.
But why? Why wouldn’t you want to your Aux to pan with your track?
Well say you want to create a panning echo effect. So you hard pan a guitar to the left, but want the echo to come from the right.
With Post Fader, you’re able to hard pan the Aux to the right independently from your original track. Giving you flexibility with your Auxes.
But if you turn that guitar up or down, the Aux will also get louder or quieter.
The final frontier. Pre Fader sends your audio before either your channel fader or your panning.
This gives your aux complete separation from your original track. It’s like you created a copy of your track. And now you can process it however you want.
And even if you mute the original track, your Aux won’t stop playing.
But Why Bus to Begin With?
So why use a bus to begin with?
There are a lot of reasons! Most often it’s to save you CPU by sending many tracks to one effect, instead of loading tons of effects.
Here are 4 reasons to use Bussing in Logic:
1. Save CPU by Sending Your Tracks to Effects
Plain and simple – plugins take CPU to run. And the more you have in your session, the more CPU they need.
Hate System Overloads? A huge step to kicking them is to send your tracks to an effect instead of loading the same effect on every track.
For example, if you want to use Space Designer for a nice hall reverb, you could either:
- Load Space Designer on every track, or
- Send every track to 1 instance of Space Designer
And this works for Delays, Parallel Compression, and anything else you might want to blend with your tracks.
2. Grouping Instruments With Track Stacks
Another great reason to use a bus is when you want to process a group of instruments together.
The classic example is when you want to process a drum kit. You can do this by setting the Output for every drum to the same Bus:
And now you can EQ, compress, or do anything you want to the entire kit.
Want a fast and easy way to group your instruments together? Use Track Stacks.
Select every instrument you want to group, and hit key command Shift – Command – D.
Logic will create a new Bus and Aux, and route all your selected tracks through that Bus to the new Aux.
3. Send All Your Tracks to a Submix
Sometimes you may find that you wish you had a Stereo Output before the Stereo Output.
For example, you might want to use EQ or compression on your whole mix.
But say you have a Reference Track in your session to compare your mix against. Well, any EQ or compression you use on your Stereo Output will also affect your Reference Mixes.
But if you send all the tracks in your mix a separate Aux, you can process your whole mix while leaving your Reference alone.
That’s what a Submix is for. It’s basically a Stereo Output for your mix before the actual Stereo Output.
So if you have tracks you don’t want to process, don’t send them to the Submix.
4. Headphone Mixes
Sometimes when you’re recording a musician, they want to hear some instruments more than others.
And if you’re recording more than one musician, each one may want a different headphone mix.
By sending your mix to separate Auxes, you can send those Auxes to separate headphone outputs.
And then you can use the Send Levels to create custom mixes for your musicians!
In this case, you can send all your tracks to a new Bus. And with that Bus, you can set its Output to a Headphone or Balanced Output.
Voila! Now you have a separate Headphone Mix for your musician. Just adjust the Send levels to create a custom mix.
Bussing in Logic Pro X is too helpful to ignore. And with the ability to route audio wherever you want it, you can do some pretty cool stuff.
- A Send is the on-ramp to the
- A Bus, which is the pipe to
- An Aux, which is the channel
Don’t forget your routing options either:
- Post Pan means you send both your panning and fader level to the Aux
- Post Fader means you send your fader level, but not your panning to the Aux
- Pre Fader means you send the audio without any panning or fader levels to the Aux
Claude Gillet says
Thank you Chris! This is very well explained. Are there some rules on how to set the effects on the aux channel, like the amount of dry and wet signal?
You bet Claude! And absolutely – the general practice is to set the mix on the reverb, delay, or anything else to 100%.
The reason is because the Send level or Aux Channel Fader now acts as your “mix” knob. Because you can drive the effect as quiet or loud as you like.
I’ll update the post to reflect this question. Thanks again!
Claude Gillet says
Steven Clemente says
Thank you very much! This was a great answer and explanation to a question I had.
I think I now understand the difference between Reference, SubMix, Stereo Out and Master channels in Logic:
The Reference Track is not your own audio but contains audio that you have imported which is a good example of someone else’s mix for you to compare with your mix.
The SubMix is an auxiliary channel that you create and bus all your tracks to except for the Reference track.
The SubMix is the channel that you add the Mastering plugins (EQ, Compression, Adaptive Limiter, etc.) to and perform the Mastering on.
All the channels are sent to the Stereo Out.
Leave the Stereo Out channel alone, without any added plug-ins, so that when you listen to the Reference track it is unchanged.
Unless you are working in Surround sound, it is best to leave the Master channel strip fader at ‘0’ and forget it exists.
When your mix is complete do you simply delete or mute the Reference track and leave everything as is or do you then copy the SubMix channel to the Stereo Out and delete the SubMix channel?
Thanks Steven! I agree with everything you’ve stated 🙂
When I’ve finished a mix, I’ll simply leave the References muted or powered down. But you’re more than welcome to remove them from your session.
For the Submix, I just leave that in the session. Doesn’t hurt anything to leave it with your preferred processing.
Great! Thank you very much for reponding and answering!!
Thank you Steve, for simplifying some rather complex processes. I just have a follow-up question about sending tracks to effects. For instance, if I send a number of tracks to Space Designer, am I limited to only using the same setting on each sent track, i.e., if I want a large plate effect on one track, a short hall on another and still other types of reverb on various tracks, can I change the Space Designer settings for each individual track or would I have to create additional buses with additional instances of Space Designer to achieve different types of reverb on different tracks?
Hi Logickelly, thanks for your comment.
In your example, if you want:
– One track to have a Plate Reverb
– Another to have a short hall
– And another to have a different style of reverb
Then you’ll need to create a send for each of those effects. Thus, you’ll need 3 Sends/Busses/Aux Channels, each with a different reverb.
ROBIN M SETTY says
Wow – great explanation! Does the order that I send to busses matter? in other words are they processed in parallel or in series. This is what I’m asking: I have an audit to which I want to add delay but I also want that delay to have reverb, do I (a) send the audio first to the delay bus and then to the reverb bus or do I need send the output from the delay aux channel itself to the reverb bus?
Aru Junior says
No reply from the teacher?
George Palmer says
Every time I read another of your posts, I’m more convinced that YOU ARE THE MAN! Great explanation of something I was afraid of.
Thanks so much George! I really appreciate the kind words 🙂
Hello Chris my only thing with busses in logic is that my volume always increases verses when I use another program it doesn’t it only increases the effect on the track. Is there any way in logic I can just increase the effect on a track with adding the bus affect like other daws.
Matt Sheridan says
Excellent article — extremely clear and simple!
Kc Nash says
Thanks for the explanation. I am having trouble. I have Logic Pro x on my iMac Pro and insert my mic into input one on my apollo. I have my main audio track where I have no effects other than the inserts on the console in my apollo mkii twin solo external Audio interface. For reverb say I’m using a space designer. When I send to bus 1 from Audi one with the output as stereo out. To the autocreated six track input bus one output stereo. I insert space designer make sure volume is turned up on knob and I get no audio signal what so ever? What reason could this be? Does my aux (bus) output need to be sent to something different than Stereo out because I am using an external audio interface? I know I’m making this much more confusing than I’m sure it is, but all of my plugins work in my console on my apollo 610b antares etc… why aren’t my busses working with in my daw? I want to use while recording live time for the most part Just reverb maybe noise gate? Can you or anyone please help? I can take a picture showing i have it routed correctly..
Travis Bear says
When would you send channel output directly to a bus, versus leaving the channel output at its default setting and using a send?
You may already have an answer for this but since Chris hasn’t posted replies for awhile I thought I’d answer you. If you’re using the exact same effect (like the same delay) on multiple instruments (e.g., guitar, keyboard, snare, etc.) then it makes sense to put that effect on an aux channel and use a bus on each of those instruments to send to the effect. This saves processing power because it is only added to the aux channel and isn’t added to the guitar channel, the keyboard channel, the snare channel, etc. individually. However, if you’re only going to use that delay on ONE instrument (like a guitar) and not share it with anything else there is no reason to put it on an aux channel because it won’t be shared, so just add it to the guitar channel directly.
Thanks so much for helping out Wade! I appreciate it when WLPR readers hop in 🙂
Chris, great article! But can you explain to me how to bus an unaffected signal to an Aux?
It seems to me, even with Pre-Fader, any FX’s on the sending track will get pushed to the Aux.
I’m looking for a way to get a clean copy of the track so I can add separate effects, but right now, my only method is to duplicate the audio onto another track, i feel like that is just wasting my CPU and storage space…
Let me know if you have any tricks to accomplish this!
Matt Clark says
Chris, my name is Matt. My band and I are trying to figure out logic pro 10 and I had some questions. The main reason we are using this software is that it came pre loaded on the lead singers laptop and it is a great opportunity to stream line our PA/ monitoring systems for live shows. We want to be able to make aux channels to route through our interface for in ear monitors while at the same time creating a house mix (a lot of our venues don’t have house pa systems). my main question is can a single aux channel have multiple inputs? Guitar, guitar, bass and vocals all in to each musicians own channel. I know that each channel can send to multiple busses. I hope this makes sense.
Hello, thank you for explaining it in an easy way. I’m new to logic pro and I’ve got some preset bus settings and the instructions tell me to add it to the bus folder under channel strip settings however I don’t have a bus folder there. i was wondering if there was a way to create it or if there’s something I’m able to do.
Thank you for this article, it was a life saver! Your explanation is clear and straight to the point. I use your website so much to learn about Logic, as I’m mixing my own demo and your tutorials have truly been amazing in helping a rookie like me. Keep up the excellent work!