Subgrouping on an Allen & Heath GL2400 32 channel

[Brad Weber]

Originally Posted by Rockwoodbass

1) I'm a newby
2) I didn't wire our system.
3) L R Outs feed one amplifier and set of speakers; Mono Outs feed another amplifier and set of speakers.

I followed the steps outlined. I can get subgroups to feed the L R Outs but I can't figure out how to route the subgroups to Mono. Is it possible to do? What else do you need to know?

That is not as simple to determine with the GL2400 as the Mono output has three potential sources depending on what you are trying to do and how the buttons above the Mono output fader are set. It's an easy thing to show on the mixer, but much more difficult to try to describe in writing.

It sounds likely that you should be in "FOH" mode rather than "MONITOR/LISTEN WEDGE" mode, thus the top button above the Mono fader out or not engaged. In that mode the second "M SOURCE" button then selects whether the Mono output is a sum of the Left and Right signals, the "MONO (L+R)" mode, or if it is the Aux 6 signal, the "AUX 6 (AUX FED SUB)" mode.

If you are getting audio to the Left and Right outputs but not to the Mono output then the "M SOURCE" button above the Mono fader is probably pushed in for the "AUX 6 (AUX FED SUB)" mode. If that is the case then the Mono output is the AUX 6 mix and independent of the main stereo mix or the Subgroups.

If you want the Subgroups routed to the Mono output then you would need to a) have the top button above the Mono fader out or not engaged to select "FOH" mode and b) have the lower "M SOURCE" button also out or not engaged to select the "MONO (L+R)" mode.

[Rockwoodbass]

You describe the procedure well in writing. Thanks. I discovered that we typically run in Aux Fed Sub mode for some reason. I deselected both Monitor/Listen and Aux Fed Sub mode and selected "Rev" for Aux 5 and Aux 6. This seems to work (I was able to test the board only during a meeting); I'll check it fully tomorrow evening. Part of the problem is that our venue is used so heavily that I don't get much time to practice and document.

[Rockwoodbass]

This worked. I'm curious, though. Since you didn't mention Reversing Aux 5 and 6, do you think that the guy who set up our system set some jumpers that I'm not aware of? I realize that you don't have long-range xray vision, but I'd appreciate your thoughts/opinion.

The board is very flexible, and use it for both FOH use and monitors (I can do this when not using Groups; haven't tried to use it with Groups and don't see a real need for it yet).

[Brad Weber]

The "REV" switches for the Aux sends usually relate to whether the console is being used for FOH or monitor use. Essentially, they swap the controls and actual outputs for the Auxes and the Groups/Mains.

For example, in "FOH" mode Aux 5 has a turn potentiometer and an AFL switch for controls and is then a 1/4" TRS output while the Left output has an insert, fader, AFL, mute and meter which then runs to an XLR output. In "MONITOR" mode those are switched with the Main L signal using the Aux 5 pot and 1/4" output while the Aux 5 signal takes the path the Main L signal normally takes with a fader, mute, metering and an XLR output.

The same happens between Aux 1 and Group 1, Aux 2 and Group 2, Aux 6 and Main R, etc. if you select to "REV" the associated Aux.

The idea was that in a FOH mix setting you typically want metering for and more control of the Group and Main outputs while in a monitor mix use it is beneficial to have the greater control and metering on the Aux sends for monitors.


Groups can be very handy in some applications. For example, assigning all of the background vocals to one Group and then that to the Mains can let you control the level of all of the background vocals with one fader or perhaps insert a comp/limiter or other processor on all of the background vocals without affecting anything else. Similar with drums, keys, horns, etc. Or even more basic, assign the entire band to one Group and now you can control the level of the band with one fader, mute the band with one button, etc. without affecting any of the other inputs.

[Rockwoodbass]

Thanks so much for your expertise. I've got groups working (with the red sliders) and Dress Rehearsal is Saturday, so I won't tinker any more at this point. I know enough now to know that I need to spend more time with the board and manual. I'm still not sure whether our board is set up for FOH or Monitor mode or how to switch modes, but I can figure that out after our production is finished.

[SterlingAug]

Finding this thread finally solved our dilema in understanding how groups work on this A&H GL2400 mixer. No one could explain it to us enough so we could understand it.

I expect our Easter Sunday service video will now sound excellent on our website.

Thank you all.