The difference between Busses and Aux

[lebouche]

As I have no experience with recording with a proper desk (mine is a glorified patchbay/monitoring system) I'm often wondering what the difference is between busses and Aux sends.
The obvious one I see is that the busses have no send ability...so the Aux is meant to feed a bus but why? Each of my tracks in logic have sends...mayve its just a simpler way of grouping things and giving them the same send treatment.
This is fundemental and I'm sure very basic but hands open I'm clueless
:Redface:

[seagate]

As I have no experience with recording with a proper desk (mine is a glorified patchbay/monitoring system) I'm often wondering what the difference is between busses and Aux sends.
The obvious one I see is that the busses have no send ability...so the Aux is meant to feed a bus but why? Each of my tracks in logic have sends...mayve its just a simpler way of grouping things and giving them the same send treatment.
This is fundemental and I'm sure very basic but hands open I'm clueless
:Redface:

I thought it was the other way round, Busses feeding the AUX!?
At least that the way I use them in Logic. As far as I know there is no differences apart from the added routing options in the AUX.

[Brendo]

I'm not sure how it works in Logic yet, but I know that in PT, Busses are like virtual patch leads, sorta, with Aux tracks performing both somewhat like Aux returns (Where you send to the input of an Aux track, and put an effect on it, and "Busses" like on a console (when you "buss" your drums to a single fader, for example).

There's no direct real-world equivalent to the PT Aux and Bus implementation - it's adapted to work well within the software.

[otek]

Like Brendo says, the aux/bus implementation in Logic (and PT) is a software-optimized solution, even though you can achieve similar routing options on many large-format analog consoles.

In Logic, the Aux objects are similar to Buses only in that they have insert slots, can be configured in mono or stereo, and are designed for complex signal routing. But that's pretty much where the similarities end. Instead of being a "passive" receiver of multiple channels (you can't configure inputs on a bus, only on the channels/objects you are sending to it), the Aux objects can be configured to accept input from either the physical inputs on your soundcard, Bus objects, or Multi-Channel Instrument outputs. The Aux objects can be configured in mono or stereo, and I believe up to 128 are available (not sure how this works in Universal Track Mode, because I never use it).


So how can this be usable?


Well, if for example you have all your drums bussed to Bus object 1-2, you can set an Aux object to receive the output of Bus 1-2, thus enabling mono or stereo FX processing on the bus, parallel compression, or the like. And since you can set up a large number of Aux objects, you can feature all sorts of different processing on the same bus, since multiple Aux objects can accept the same bus outputs.

If you have an outboard reverb or other hardware you would like to incorporate into your session, you can configure the Aux object to accept inputs from your sound card and, provided you have enough extra I/O's, you can use the external piece of equipment as an online FX source. Latency problems still apply of course, but this can still be useful in some cases.

Finally, if you are using Multi-Channel Instruments like the EXS-24 sampler or, say, a Korg or NI VSTi, your first output pair will be whatever Instrument channel you are using; the consecutive outputs will use Aux objects.

[seagate]

Finally, if you are using Multi-Channel Instruments like the EXS-24 sampler or, say, a Korg or NI VSTi, your first output pair will be whatever Instrument channel you are using; the consecutive outputs will use Aux objects.

Learn somethin' new everyday...

Life is good!

:D

[malice]

Very roughly:

Auxes are busses, but all busses are not auxs.

A buss is a device that is summing audio from several channels into a summing amp to deliver it without level loss.

Groups are busses
Main out L/R is a buss, called the "2buss"
Aux sends, Fx Sends, Echo sends: busses
monitor is a buss.

malice

[Tim Halligan]

Very roughly:

Auxes are busses, but all busses are not auxs.

A buss is a device that is summing audio from several channels into a summing amp to deliver it without level loss.

Groups are busses
Main out L/R is a buss, called the "2buss"
Aux sends, Fx Sends, Echo sends: busses
monitor is a buss.

malice


Obviously - with so many names that can be interchanged, confused, and generally mangled by regional variations - audio nomenclature is not an exact science. :D

However, to make life easy for you, Malice has nailed it.


Cheers,
Tim

PS. You want confusing names...work in television...:Roll eyes:

[pounce]

groups and busses are two names for the same thing.

groups on a mixer have their own output. usually logically grouped together, like all vocals to group 1 for instance. a group is a summed output for a collection of channels. so all vocal channels would go to this group. the volume control for each source in the group would be the channel volume for each item, the group mix is always controlled by the channel.

an aux is another physical output from the mixer. originally intended for hooking up auxilliary gear to the mixer, like effects processors or recorders. the difference with an aux as compared to a bux is that aux sends have a pot controlling how much each channel is sending to the aux that is unrelated to the channel volume. so you can do a totaly different mix with aux sends.

so the group channels are an output tied to the channel volumes, and the aux sends are able to independent from the channel volume settings. based on that, they are used differently. even in software i find i use them the way i would use the hardware equivelents (which they are modeled after). aux sends to my fx processors, groups for multiple channels which i want to have summed to a single slider.

[Mixerpuppet]

Very roughly:

Auxes are busses, but all busses are not auxs.

A buss is a device that is summing audio from several channels into a summing amp to deliver it without level loss.

Groups are busses
Main out L/R is a buss, called the "2buss"
Aux sends, Fx Sends, Echo sends: busses
monitor is a buss.

malice


heh heh...

A simple way to remember...

Bus's are for moving stuff around....

Aux's are like taxi's... picking up or dropping off if the bus's are full...

:)

Typically a bus is taking signal that has already come into the desk and moves it somewhere else for further processing whether sending it to an output for a recorder or the main summing section. Some 2 bus's have additional routing capabilities for different monitoring...

Auxes are for bringing in extra things once your inputs are filled up.

[lebouche]

Thank you all!
:)

[eagan]

To maybe help simplify this a little more for you, it basically all boils down to just this, in simplest form.

In general electronics terms, a "buss" is simply an electrical common connection point, that physically can run around to many places.

Keep that simple idea in your mind, and a lot that seems complex can be simplified a bunch.

In this world, it can can fairly confusing because in different situations a designer (hardware or software) can take a "buss" and designate it for a specific purpose. Then, there might be all kinds of complexities in terms of what's routed TO a particular buss, and what's routed FROM that buss somewhere else, to something else.

What might be one guy's "reverb send" might end up being someone else's "extra monitor mix feed".

Simplest version, just think of any "buss" as a common roadway for routing signals. What you then use that roadway for is another thing.

Does that help a little more?


JLE

[lebouche]

Yes thank you,
D

[otek]

groups and busses are two names for the same thing.

This is often true, but sometimes they describe two different things.

E.g. on the SSL consoles (at least this used to be the case) and also in Logic nomenclature, a group is a way of "ganging" a number of faders to make them move syncronously. On the SSL, a "group" fader doesn't pass audio, it merely controls a number of other faders. In Logic, any fader will control the whole group when moved.

A "bus" amplification stage always passes audio.

[lebouche]

Yeah that bugs me in Logic...you have to send the group to a bus...
In cubase it just has a feader and you can apply effects.
Thanks

[Skwaidu]

E.g. on the SSL consoles (at least this used to be the case) and also in Logic nomenclature, a group is a way of "ganging" a number of faders to make them move syncronously. On the SSL, a "group" fader doesn't pass audio, it merely controls a number of other faders. In Logic, any fader will control the whole group when moved.


And in PT 7.2, they added "VCA Master" faders, which control a PT "Group" just as the SSL VCA faders do... (The PT group normally acts like Logic here)

This is actually pretty cool on the ICON control surfaces as you can view VCA Masters on a custom fader page... And solo/mute/mix/acces components of the group at will. Changed the way I mix, or at least the way I use the "big mouse". :)

[Brendo]

even if you're not using an icon, can you put all the vca masters next to each other and bring it up as an 8 fader bank on a lesser giant mouse?

[otek]

Yeah that bugs me in Logic...you have to send the group to a bus...
In cubase it just has a feader and you can apply effects.

Not quite getting what you are saying here....?

Logic groups work fine without bussing, and you can select a wide variety of parameters to be included or excluded from the group.

:Confused:

[Skwaidu]

even if you're not using an icon, can you put all the vca masters next to each other and bring it up as an 8 fader bank on a lesser giant mouse?

Yes, ainnit cool? :Coolio:

[juergen]

As you're working in Logic, without being able to pan your sends - for ex. if you want your guitar to be panned hard R, and the verb hard L - you can also send to an aux first, configure its output to go to the verb (in this case), and use the aux's panpot to pan hard L of the verb for the guitar.

Hope that made sense.

[lebouche]

Not quite getting what you are saying here....?

Logic groups work fine without bussing, and you can select a wide variety of parameters to be included or excluded from the group.

:Confused:

But theres no group fader unless you route each grouped track to a buss..

[otek]

But theres no group fader unless you route each grouped track to a buss..

That depends on what you mean by "group fader" - in Logic, any fader can be the master object, move one and the others follow. What would be the advantage of having a separate "control fader"?

[lebouche]

Not having to route to a bus...like in cubase.:)

[otek]

Not having to route to a bus...like in cubase.:)

Lebouche, you are missing my point.

I just went through telling you that group fader control (as well as a host of other parameters) is very much possible in Logic.

The only difference, if I'm reading you correctly (and understand your description of Cubase), is Cubase will assign one master control fader to your group, whereas Logic makes all the faders included in said group move interactively.

My question to you is, what would be the advantage of having a separate control fader for a group? Mind you, NOT talking about passing audio, merely controlling fader objects.

[Skwaidu]

My question to you is, what would be the advantage of having a separate control fader for a group? Mind you, NOT talking about passing audio, merely controlling fader objects.

Screen clutter would be one. With PT's new Master Faders I can have a full "stems" submixer on one part of the mixer, so I can try alternative balances fast without having to scroll around even in large sessions... I gather it can be very handy even without an ICON though with it these are *very* cool, with a dedicated fader "page" for VCA Masters...

[otek]

Screen clutter would be one. With PT's new Master Faders I can have a full "stems" submixer on one part of the mixer, so I can try alternative balances fast without having to scroll around even in large sessions...

That sounds like a great idea. Didn't think of that.

Lebouche, was that more or less what you meant as well?

[lebouche]

Yes...that and passing audio so I dont have to copy the same send or eq on to each audio track.
Thanks

[Skwaidu]

Screen clutter would be one. With PT's new Master Faders...

(Just to clarify more, I was talking about the new to PT VCA Master Faders above... And yes, they're handy. :Wink: )

Yes...that and passing audio so I dont have to copy the same send or eq on to each audio track.
Thanks

Unh... VCA Masters *DO NOT* pass audio. That's the whole point. Subgroups("Aux Inputs" in PT) pass audio and can have inserted processing...

[lebouche]

Yes but also wanted a master fader to pass audio as you mentioned. I thought if you group stuff and added an eq/plugin it should at the least be added to all the tracks but no...
you have to add it to each member of the group.
Thanks

[otek]

Yes but also wanted a master fader to pass audio as you mentioned.

Well..... isn't this exactly what you're getting if you assign the desired channels to a bus?

Are you yanking my chain here? :Wink: (or in UK nomenclature, "taking the piss"....)

I fail to understand the problem.... you complained about the fact that in Logic, in order to have simultaneous fader movement, you have to assign the faders in question to a bus. I tell you that you can achieve simultaneous fader movement by assigning selected faders to a group (the difference between a group and a bus have already been discussed in this thread, but for reiteration, see below). You then claimed you did not only want simultaneous fader movement, but also....

a master fader to pass audio

....which is the sum and total of what a bus is. So let me get this straight, you want all the functionality of a bus, but without sending it to a bus?

This is not making any sense to me.

I thought if you group stuff and added an eq/plugin it should at the least be added to all the tracks but no...

When you're doing bus processing, you add the plugin to the bus fader, not to each channel being passed through the bus.

Unless all you want is synchronous fader movement, in which case you assign selected faders to a fader group.

If you want to add all plugins with identical settings to each channel included in a bus or group, you simply select the copy channel command from the pull-down meny in the insert section (if you're on Logic 7). But basically this gives you the sound of the channels being processed individually.

To my knowledge, this is how most DAWs work, including Cubase. Someone correct me if I'm wrong, please.


Now, to reiterate:

A group is a way of making several channel faders act synchronously. It doesn't pass audio, merely controls various parameters of selected fader objects.

A bus is a summing device that sums the audio of several channels. By nature of its operation, all audio passed through it will react synchronously and proportionally to processing and fader moves made on the bus.


Not harping on you here, LeBouche, just trying to understand what you mean. Please be a bit more specific in your answer as to what you want to accomplish, and it will be easier to help you.


Cheers,

otek

[otek]

Just to clarify.... Skwaidu mentioned "Subgroups", which is the same thing as "Buses" in Logic parlance.

And "VCA Masters" do the same job as "Fader Groups".

[lebouche]

Think I'm a bit conf.
Simply put in the Cubase version I started out on a group was like a bus and it also linked all the faders, v useful for putting the same eq on several bvs or guitars etc.
In logic you have to go through the palava or routing to a buss as well as grouping...thats all
I'm gonna read your previous post again cos I'm tired and didnt take it all in to well.
Thanks

[otek]

Simply put in the Cubase version I started out on a group was like a bus and it also linked all the faders, v useful for putting the same eq on several bvs or guitars etc.

LeBouche, as far as I know, Logic and Cubase work pretty much exactly the same in this respect - a fader group is one thing, and routing through a bus is another. If not I would appreciate if one of the resident Cubase Jedis would set me straight on this matter.

Read above for an explanation as to the difference between a group and an aux. Having both on one fader would not be very smart, because the whole idea of the bus fader is to provide master control of the audio passed through the group, and its associated processing.

You could route audio through a bus and at the same time, set up a fader group on the routed channels. I do it all the time - though it gets more complicated in terms of how the audio routed through the bus responds to the processing. For example, if you have a compressor strapped across the bus, the amount of compression will be severely affected by the settings of the fader group. If you lower the faders in the group, the compressor will see less signal and therefore compress less, changing the sound, and also creating a rather unpredictable level curve.

Typically, if I chose to do this, it will be in a situation where no dynamic processing is applied to the bus.

[lebouche]

A)
LeBouche, as far as I know, Logic and Cubase work pretty much exactly the same in this respect - a fader group is one thing, and routing through a bus is another. If not I would appreciate if one of the resident Cubase Jedis would set me straight on this matter.



B)

You could route audio through a bus and at the same time, set up a fader group on the routed channels. I do it all the time - though it gets more complicated in terms of how the audio routed through the bus responds to the processing. For example, if you have a compressor strapped across the bus, the amount of compression will be severely affected by the settings of the fader group. If you lower the faders in the group, the compressor will see less signal and therefore compress less, changing the sound, and also creating a rather unpredictable level curve.

Typically, if I chose to do this, it will be in a situation where no dynamic processing is applied to the bus.

I get you on most of this.

Re. A) it was Cubase VST for any Jedi's info.

RE B) I always accepted that was just something I had to do...adjust the threashold on my bus compressors according to the mix.
How should I compress a group of eq 4 vox then? I always thought it made sense to do that- if just to save processing power.
Thanks

[otek]

Re. A) it was Cubase VST for any Jedi's info.

Cubase VST happens to be a platform I actually did work on to some degree - when it was still around. As I recall, what you had there was a regular bus architecture, although quite a bit more simple and less powerful than current versions of Logic or Cubase SX. The matter is somewhat academic at this point, since Cubase VST has been out of production for several years.

B) I always accepted that was just something I had to do...adjust the threashold on my bus compressors according to the mix.

You don't understand the problem I am talking about.

When you adjust faders on channels routed to busses, you are changing the way the bus processing hears the summed tracks. If you for example lower the levels of the individual channel faders, any dynamic processors strapped across the bus will compress the audio less. This will create some extremely unpredictable dynamic behavior in your mix. For every time you decided to change the levels, you would also have to change the settings of the bus compressor, and if you were using automated level rides - forget it.

This is also slightly beside the point of the original post, which was the ease of usage of fader grouping and bussing on various platforms, and I can tell you one thing with a tremendous degree of certainity, and that is that any modern version of Cubase or Logic is WAY beyond Cubase VST in anything concerning routing and automation. Trust me. :D

How should I compress a group of eq 4 vox then? I always thought it made sense to do that- if just to save processing power.

Aaaah, but now we are getting somewhere.

(I am assuming you mean to "compress a group of vox", because I don't know what you mean by "compress a group of eq 4 vox")

Assuming you have no desire to affect the individual level relationships between the different tracks after the fact (in which case I would recommend separate processing), I would assign the four tracks to a bus, strap a compressor across the bus, and get my individual track balances to work with the amount of compression I want to apply. The idea is to make the compressed bus work as a good-sounding whole (for example on a number of backing vocal tracks). Then, if I wanted level automation of the four tracks as a whole, apply that automation to the bus itself. This way, the internal balance of the individual channel faders would not cause unpredictable behavior from the compressor. The levels "pre-bus compressor" would remain static, but the whole of the group would change.

[lebouche]

Thank you, after further exploring I feel a little more at ease.
You the man Otek:Thumbsup:

[airborne]

Sorry to bring this thread up again, technical question. You should be able to grab yer Aux Object and go Input-->Bus right? Even in express? I'm working with a Logic Express rig at the moment which displays 'No Input' under 'Input' on the auxes.

[jord]

Sorry to bring this thread up again, technical question. You should be able to grab yer Aux Object and go Input-->Bus right? Even in express? I'm working with a Logic Express rig at the moment which displays 'No Input' under 'Input' on the auxes.

There's a chance that Express may only allow input from multi-channel instruments. Bus input could very well be a Pro feature (wouldn't be surprised).

jord

[AxeSlash]

I've always looked at it like this (this is the standard for most analogue consoles I think, the terminology becomes somewhat variable inside a DAW as to what the phrases can mean and what certain things are called):

Groups and auxes are types of bus.

Groups generally have a "fixed" send level - i.e. whatever level is present at the fader is what gets sent to the group.

Auxes have a "variable" send level - and can be pre or post fader, so for example if it's set to "pre", the level sent to the aux is entirely independant of the channel fader. If it is set to "post", the level sent is both dependant on the aux pot for that channel AND the channel fader.

I mainly use Groups as a way of mixing lazily; I tend to group stuff together - I generally end up with a group each for drums, guitars, bass, vocals, keys, and anything else I have multiple tracks of. I may even go as far as splitting guitars into lead and rhythm depending on what I have to work with.

Almost everything goes through these groups BEFORE going to the 2bus (aka L/R or Master or "ST" if you have a Yamaha desk).

The idea being that if you want to do something to EVERY vocal track (e.g. EQ), you can slap an EQ across the group and therefore not have to EQ every channel individually, meaning that if you decide that your vocals aren't sitting well in the mix, you can change ALL the EQ on them in one easy move by EQing the group, rather than having to change a load of separate EQs on the individual channels. Lazy at first glance I know, but well worth it later down the line.

The other thing one can do with groups is to bus stuff through a device with intention of having one thing affect another. For example one could compress the drum group to make the snare and kick imply that they are cutting through the cymbals more (even though it's actually the cymbals that are dropping in level). Or even vice versa if you really wanted to. This technique is called "inserting a [piece of gear] across a group".

Auxes I generally use to send to effects and do parallel compression. Here I would set up an Aux to feed into e.g. a reverb, then the outputs of said reverb would return into a separate pair of channels. The advantage of this is that one then has control over the amount of level sent TO the reverb, and also over the amount of signal coming OUT of the reverb (and then to the 2bus) by using the channel faders. I can also EQ/compress/whatever this by inserting an appropriate bit of gear across the reverb's "return" channels (the two channels where the reverb's output are plumbed in). Parallel compression is done the same way. Whether the sends are set post or pre depends on the scenario and what one is trying to achieve.

This is known as a "send and return" setup.

One can also do parallel compression by sending a channel both to the 2bus AND a compressed group, but that way doesn't give you much control over what you are putting into the group (you only have a switch as your send control rather than a pot, and anything you do with the channel fader affects what is sent to teh 2bus as well). I prefer an aux set to "post", and treat the compressor pretty much as I would an effects unit. But maybe I'm doing it wrong, I'm still pretty new to parallel compression.

[HOOK]

To back things up a bit:

When sending a signal through a channelstrip (Mixer or DAW the like) the most simple routing is the "default" routing to the MainMix/L R; just Mix many signals into (most of the time) two signals.

With this routing you can (besides alter the level of the signal) manipulate each signal either parallelly or in series.
The series (is that the right eng. word for it?) is the inserts and the parallell is your Aux (aka: Cue, Mon, Fx, sends ....)
The Aux can either be post or pre fader ie affected or nonaffected by your fadermovement.
The PreAuxes is generally used for Cue (or monitor if you prefer) mixes as you (most of the time) dont want any faderchanges to alter the cuemix.
The PostAuxes is generally used for FX as you (most of the time) want any faderchanges to alter the FXmix.

Both Aux and L R/MainMix are Busses, in fact anything that can sum many signals into one (or two if stereo is needed) is called a buss (from Greek Omnibus) Think of (Greyhound)Busses they transport Many people.

On hardwaremixers its like this:
Aux is an additional exit - a way to split one signal into two (or more) signals for separate processing.
Buss is a channelstrip that gets fed, not from outside the mixer (ex a mic.) but from other channels - a way to sum many signals into one and therefore can be processed as one.

DAWs make this a little more complicaded, but then you get the principals of signalflow IRL its allmost the same. allthough DAWmakers tend to "rename" things and sometimes use a Buss as an Aux. (or so it seems) as they lety you send part of the signal to a buss with an Fx inserted in the signalpath to acheive the same thing as the IRL Auxes let you do on a RL Mixer.



HOOK

[HOOK]

...and what Axe and I just did must be an example of AUX as it was parallell!!:lol: :lol: :Roll eyes: :Razz:




HOOK