Newbie question(s) on Soundcraft GB4

David Kulick

New member
Jul 20, 2018
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By way of introduction, I'm new to this but I don't have a day job. I'm a retired computer programmer living in a 55+ community that has a 350 seat theater with a Soundcraft GB4 (32 channel) board. We mostly get tribute bands - this coming year we have the Rolling Stones, Doors, Creedence, Neil Diamond, etc., and some small local bands and old crooner folks. I started helping out last year, setting up monitors and cabling instruments and learned how to use XLR cables, direct boxes, and such. I also handled one of the two spotlights. The sound guy isn't available for most of the shows this year and I'm going to be handling the board.

I pretty much understand the GB4. I've watched every youtube video on it (and similar analog boards), and I've read the manual several times and sometimes I just sit there and play with it and figure out how it works. Most videos ignore the group and matrix sections, and we never used those before, but our sound guy always brought two SM57s to mike the drums (one kick, one overhead) and since we won't have those mikes, I bought the Shure PGADrumKit7 and a second 8 channel snake to handle those seven mikes. If nothing else, we should end up with a cleaner drum sound.

My plan is to dedicate channels 25-31 for the drums, and I've watched every video on how to mike drums. My plan is to use a group for them, and that's what I don't fully understand. This line is from the manual explaining the mono input channels: "The signal is sent to the stereo mix bus, centre bus and 4 group busses using the C, L+R, 1-2 and 3-4 switches. Note the use of group 1 & 2, and group 3 & 4 as 2 sets of stereo pairs." My idea was just to send all the drum mikes to group 1 (not L+R as we've always done with each input channel) and have group 1 as the master volume for all the drums, feeding that into L/R. We really only need Left since our system is essentially set up as mono, something I'd like to change in time, but currently the left channel goes to the entire front speaker setup (left, right, center, sub). The right channel goes into some ring speakers set up 2/3s of the way back, and I have no idea why we need those. I don't plan on keeping them on unless you folks have an idea why they're needed. It isn't like this is Giant's Stadium.

I think I understand the idea of 2 sets of stereo pairs. If I don't use the L+R button, but instead use the group 1/2 button for the drum channels, the signal should go into groups 1 and 2 equally, unless I pan it, but I don't plan on doing that. The group section in the manual is a bit skimpy, but it seems that I can send each group into L/R and/or Center, and there's a Pan knob as well although again I don't need that. Do I have this right?

Also, I'm a bit lost on the use of the Matrix section. Each group (1-4), and the left, right, and center outputs can be sent to Matrix 1-4. Each of those goes to a 1/4" output. What are those useful for?

One of our residents is a drummer and I'm going to have him bring his kit to the theater in the next week or so and hook him up and give it a whirl. Should be educational.

Thanks for any help, and I'm sure I'm going to have more questions.