Continuing our series on the Matrix, today we'll talk about some uses for them. A matrix mix can be used for quite a number of things. Rather than try to give a definitive list, I'm going to put forth some suggestions, and some examples of how I've seen them used in various church sound settings. I'll leave it to your imagination to come up with other ideas. But don't forget to share them with the group!
This is probably one of the more common uses for a matrix mix. Of course, their usefulness is predicated on proper usage of groups. If you assign everything to the L&R mix, and then send that to a matrix for recording, you have a glorified level control. If on the other hand, you split your band into say, Drums, Guitars, Keys, Vocals, Lead Vocals, Speaking Mics and Computer/Video, you can actually create a separate mix that will sound good on a recording. Not as good as a full channel split, but better than the house mix.
There are two ways to approach this. The easy way is to assign the L&R mix to the matrix you wish to record from. Then use individual groups to feed into that matrix to boost the lower level signals. This is sort of a "mix-plus." Start with the house mix, and add more of what you need. This is what we were doing at Crosswinds when I started mixing there. It's not elegant, but it works.
A better way is to leave the house mix (the main L&R) out of it, and build a new mix straight from the groups. This way, you'll get a cleaner mix, and you'll have more control over it. It does require that you check in on it once in a while, and it's one more thing to manage. But if you have the bandwidth, you'll get better recordings.
Lobby/Cry Room/Overflow Feeds
Another common usage for a matrix mix. What's wrong with just sending a house mix? Excellent question. Unless your band is playing/singing in a sealed box, or in another room, they are contributing some energy to the house. In our current setting, the drums are hardly in the PA at all. They make enough sound all on their own. So if we sent a house mix to an overflow room, they would get almost no drums and the mix would sound dead and lifeless. Using a matrix would allow us to dial up the drums to a level where they actually sound good.
If you have ceiling speakers in the lobby, you may find they don't put out a lot of low end. In fact, they probably sound pretty bad when you try to put a lot of low end into them. By setting up your groups with this in mind, then building a matrix mix that dials the bass and kick back a bit, you'll get cleaner sound in the lobby. And you won't be replacing blown speakers as often.
When I was engineering at the church I referred to yesterday, we used the matrix to feed various zones of speakers in the house. To be sure, not every situation warrants this, nor is it always a good idea, but sometimes it's handy. In that setting, we had a Turbosound speaker system that was zoned into 3 zones horizontally and 2 vertically. The zones across the rooms were handled by the processor, but we used the matrix to control the balance between the main clusters and the down fills.
We probably could have done it using the L&R faders, sending the Left mix to the mains and the Right mix to the down fills, but that would have meant the L&R faders wouldn't have been at the same level, and that just looks and feels wrong. Using a couple of matrix mixes that were fed by the L&R mix, we accomplished the goal.
This probably doesn't get used often in churches, but once in a while it comes in handy. Just before I was hired at Upper Room, there was a funeral held that received quite a bit of media coverage due to the situation. Often, news photographers will want to get decent audio for the story and you can give that to them via a matrix mix. I'm assuming that the proper channels have been consulted for permission.
For happier events, such as a large Easter or Christmas production, local media may want to get some footage. On-camera audio is going to sound terrible, but a matrix mix will present everyone's hard work in the best light (er, uh sound).
Certainly there are other uses for a matrix mix, but all that I can think of are derivations of those listed above. Hopefully, this gives you an idea of what you could use all those extra knobs for. And if you have a creative use of a matrix mix, please share it with us. If there's one thing I've learned in the last 20 years of doing sound in churches it's that there's always something new to learn. In our next installment, we'll touch on how the matrix differs in some of the newer digital boards.