Perusing the Behringer website they have all different notations for Bus. What does it mean to be a 4-Bus mixer compaired to a 4/2-Bus mixer? Or, even a 2/2-Bus mixer?

I don't believe the current answer is clear or useful. Please review the products above which have pictures of the Mixer. For instance, the 2/2 mixer bus has 3 labeled "aux" and one labeled "FX Send" how does that make 2/2 with the below answer?

Behringer X2222USB

  • There are three aux busses. Two are red in the picture. They are both capable of sending pre fader. The yellow FX bus is post fader only. That is your 2/2. Apparently, Behringer decided that the sub-mix busses and the pre-fader aux busses were the important ones to include in the product name. You are looking for standards where there are none... like I said.
    – JoshP
    Nov 9, 2012 at 2:10
  • I can appreciate the frustration with the lack of a standard. But knowing that just means that you can't rely on the name of a mixer to divine the specs. You'll just have to read the "features" and "details" in order to get the complete picture.
    – JoshP
    Nov 9, 2012 at 2:14
  • I get that there is no standard, but certainly there must be some meaning within the same company here is another mixer, the yet to be released Behringer UFX1204 (picture of the front of the mixer). It has two-auxs which can alternate between pre/post fader. Wouldn't that make it a 2/2 mixer and not a 4-Bus mixer? Are these definitions that shitty even within the same brand? I can't help but feel that they mean something. Nov 9, 2012 at 8:30
  • In that one, designated a 1204, they're referencing the number of inputs and mix busses, 12 and 4 respectively. The aux busses are not referenced in the name of the device. Also, in following with my edit below, if Behringer was consistent with their own naming conventions, the mixer would actually be a 16/4. That is, 16 simultaneous tracks over USB going to the computer, and 4 coming back... simultaneously.
    – JoshP
    Nov 9, 2012 at 19:46

1 Answer 1


In the first place, not all brands use these designations in the same way.

Generally, an xbus mixer has x busses to sum signal. The simplest is a two bus mixer. Stereo. A left bus and a right bus. You determine what signal goes to which bus with a pan pot.

A 4 bus mixer likely isn't counting the stereo main out, and is referring, instead, to the sub-mix busses. In this case, there would be four separate busses/mixes each with independent gain control. You determine what signal goes to which bus, usually with a switch on each channel, though sometimes it will be a switch and a pan pot, etc.

The x/x slash designations are still referring to the number of discrete busses, but this time, they're making the distinction between Aux busses and Mix busses (for lack of a better term). Essentially, the number of send busses that exist. So, a 4/4 console will have 4 aux send busses and also 4 sub-mix busses.

It's an important designation because, although your mixer might have 12 or 18 etc channels, if you only have 4 aux send busses, there will be more sharing between the channels.

In short, those numbers describe the number of discrete, summing, internal pathways that lead to an output.


Ok, so after a bit more digging regarding the edit to the original question, I have the answer... at least as it pertains to Behringer, and this particular model (i.e. extrapolate at your own risk)

I asked Behringer. Their response was as follows:

The 2/2 denotes that the mixer is full duplex. What this translates to is that, via the USB connection, the mixer can transmit and receive two tracks of audio simultaneously - that would be a stereo mix both to and from the computer.

So it would seem that throwing a USB interface in there kind of changes the rules of designation.


And finally, one last communication from Behringer:

I asked:

Does the 'slash' designation always refer to the USB simultaneous I/O? Are your analog consoles described with a different nomenclature?

They answered:

The nomenclature of "2/2" is certainly used on Behringer USB mixers, though it may be different from other manufacturers. The analog boards have a slightly different designation. The 2442FX, for instance, is a 4/2 mixer. This means that is has 4 subgroups and 2 main outputs (left and right).


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