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Field Guide to AVL Renovations: Develop System Objectives

We’re continuing on in our series of AVL renovation. I should point out that almost all of this applies to new builds as well—though I hear from more churches who are upgrading and remodeling than building. Last time we talked about design, or more accurately, where in the design process the AVL guys should be brought in (answer: early!). 

Today, we’re going to talk about one of the most oft forgotten aspects of an AVL system renovation: Defining the system objectives. Put another way, what do you want the system to do?

Don’t Ask the Wrong Questions

I hear from churches all the time asking for advice. I love to give advice, so I’m happy to oblige. However, sometimes, it’s really hard. I get questions like, “We want to upgrade our sound mixer to a digital mixer. Which one do you recommend?” Or, “Which projector do you recommend for a center screen?” Or even, “We have a 300 seat room, which speakers should we install?”

Those are all questions that are all but impossible to answer. The reason is, they are asking the wrong question. There are usually several options that I could recommend. But without knowing what they want the system to do, I can’t do anything but give you brands and products I like.

The Right Questions

Before you ask for specific equipment suggestions, ask yourself some questions first.

  • What benefit to we expect to see from this new technology? How does it advance the mission of our church?
  • How will this improve our services? Will this lead more people into worship or will it be distracting?
  • What do we want this new gear to do for us? How should it be better than what we have now?
  • Who will be running it? What is their skill level, and how quickly do they learn new things?
  • Are we getting into this because it’s cool? Or are there really good reasons for this new technology?
  • What specific capacities do we need? If it’s an audio console, think inputs, outputs, mix buses, FX, remote mixing, digital snakes, personal mixers, etc. For a projector it might be how bright do we need, screen size, resolution, inputs, ease of mounting and servicing, or even should we consider a video wall?
  • Do you have a budget? Is that budget realistic?

There are plenty more questions we could delve into, but most get pretty specific pretty quickly. That should get you started.

Develop Your Objectives

Armed with the answers to those questions, you should be able to come up with a pretty clear set of objectives for this technology purchase or upgrade. With that in mind, you can start looking at options. The field will narrow quickly when you have a good idea of what you want a piece of gear to do. 

You will often find several options that will suit your needs. At that point, it comes down to what brands the dealer you’re working with carries, or which ones may have better service options. Consider which one will work with your existing equipment and even which one you like more.

Most of the equipment I’ve purchased over the years has been chosen specifically because it meets my design objectives. Sometimes it comes down to two products and I choose based on the one I like better. Maybe it’s their software, the interface, or that I have a better relationship with the rep. Those aren’t top line criteria, but they do help you decide at the end.

Above all, know why you want to upgrade or purchase. When you know why, it makes it a lot easier to come up with the what. Next time, we’ll talk budgets.

Gear Techs

CTA Classroom: Using Auxes, Groups, VCAs & Matrixes Pt. 4

We’re finally wrapping up our tour of the alternate ways we can mix a signal. Last time, we dealt with the aux and group layers, today we’ll key in on VCAs and the matrix mix.

Using VCAs

VCAs, as we mentioned before, are basically remote controls for your faders. You can assign a collection of faders to a VCA and then control the level of all of those faders using a single VCA. I use VCAs for giving me a way to control the overall mix of the band on a few faders. In our setup, we have drums, guitars, keys, perc or winds (depending on the week), BGVs and wedges. A couple of notes.

Some like to put the bass into the drum VCA, and there’s good reason to do so. I don’t because I have enough faders to do most of my mixing on channel faders. It’s a preference thing and you can try it both ways to see what works best. I also use a VCA for my wedges because I can. By assigning the aux masters that I use for monitors to a VCA, I can keep those aux masters on another layer out of my way and turn all four monitors on and off with a single fader.

This is just one of the many ways to lay out your VCAs. Image courtesy of APB Dynasonics

I’ve also created a single band VCA in the past that controlled all instrument and vocal inputs. I didn’t use it for mixing, but for taking the entire band out in one button press (on that desk, a VCA mute muted all the channels, including monitors). I still had my individual VCAs as well, and I did some mixing on them. 

Any time you want to control a group of inputs as a whole, a VCA is a great way to go. Drums are a perfect example because once you get the various drum mic's dialed in and sounding like a kit, you typically want to raise and lower the level of the drums, not the toms and hat (well sometimes you do…). The VCA will maintain the relative mix balance between the channels but give you “master” volume control over all of them. 

Background vocals are similar. Get your blend set up correctly, then mix them with a single fader. Once you see what you can do with them, possibilities abound. 

Using the Matrix

For a novice sound engineer, a matrix mix can be really confusing. I remember years ago encountering my first matrix mix. It was at a large church, and they mixed on a large analog console. In that case, they used the matrix to balance out the relative levels between the main speakers and the downfills. When the tech guy showed me that system, I asked, “OK, but how do the signals get into the matrix.” His reply was, “You just turn these knobs up.” 

I knew that. What I didn’t know was the source of those knobs. Apparently he didn’t either because he never did answer me. I finally resorted to the manual and learned it wasn’t that mysterious. 

As I mentioned in the descriptive post on the matrix, modern digital consoles have blurred the definition of a matrix. On many consoles, they can be used like auxes, in that you can send any or all channels to a matrix mix. Other consoles only let you send the groups there, perhaps with some limited number of channels.

The columns are the inputs into the matrix, the rows are the individual matrix mixes. I use this to level-balance the band and speaking mic's, build lobby and video mixes, and drive the FOH Buttkicker.

So what do we use them for? Well, in our church, I use them for sending mixes to various outboard locations; video, CD, 2-track board mix, lobby, cry room, things like that. I use my aforementioned grouping system to balance out the levels, then use eight of my twelve matrix mixes for driving those destinations.

Sometimes, you just need a spare mix for something, but don’t want to burn an aux or a group. I use a matrix for driving my butt kicker up at FOH. It’s driven by a single input—my sub aux—but by passing it through a matrix, I can set the delay for FOH and have an easy, single-fader control for level in the booth.

I also use a matrix mix for my FFT analyzer. By putting both L&R into a mono matrix, it combines them and makes it easy to compare the output of the desk to the measurement mic. This allows me to pad the level down so it matches up properly in my audio interface.

Uses for a matrix are really limited only by your imagination. Just don’t overcomplicate the system just so you can use all your matrix mixes. Remember, the goal is not to use 100% of the capabilities of the board just because you can. We use these tools to make life easier and get done what we need to.

And that’s the goal of this whole series; to give you ideas on how to use the tools you have to the greatest good. Now go read your manual and come up with some better routing ideas...

As we wrap up, I want to link to ABP-Dynasonics. Not only do they make great analog consoles, they also have some of the nicest drawings of those consoles on the web. I'm thankful they are available as they make great reference pictures. I reviewed a ProDesk 4 a while back; it's a great mid-priced analog console.

Today's post is brought to you by Elite Core Audio. Elite Core Audio features a premium USA built 16 channel personal monitor mixing system built for the rigors of the road. For Personal Mixing Systems, Snakes, and Cases, visit Elite Core Audio.

CTA Classroom: Using Auxes, Groups, VCAs & Matrixes Pt. 3

After our little theory discussion on how Auxes and Groups work, let’s get into some practical application. I’m not going to try to be exhaustive here; there are many, many different ways to use all four types of controls. But hopefully, this will give you some basic ideas as to what you can do with these things. 

Using Auxes

The most common use of an Aux send is for a monitor mix. The rule of thumb for this is to use a pre-fade mix (that is, the house fader will have no effect on the aux mix) for monitors so that any mixing changes you make in the house will not effect the monitors. On most desks, aux mixes are mono, but sometimes you can combine two auxes to form a stereo mix. Stereo is ideal when using ears, though occasionally we’ll see stereo wedges. Different consoles make stereo auxes differently, so consult your manual.

On this console, the first 4 auxes can be paired in stereo with a button press. Notice the pre button to set a pair (1&2, 3&4, etc.) as pre- or post-fade. Image courtesy of APB Dynasonics.

Think of each row of aux controls as another row of faders, but instead of moving up and and down, they rotate. By adjusting the levels of each of your channels in an aux mix, you build that mix for a monitor. At least that’s one use.

The second most common use of an Aux is for effects. Let’s say you want to put some reverb on your vocals. Now, you could buy a reverb unit for each vocal, and insert it on each channel. But that gets expensive and complicated, and it’s tough to control when the reverb is on or off, and how much reverb you have. The smarter way is to use an aux mix. FX Auxes are typically post-fade because if we turn the channel down in the house, we also want less of that signal going to the effect unit.

In this case, you’d take your vocals, and send them all to a post-fade aux. The output of that aux goes to your reverb unit. The output of the reverb then comes back in on a return or another input channel. You can now control not only the level of reverb that gets added to the mix (by the return channel), but you can also control how much of each vocal goes into the reverb. You may want to vary that depending on the voice. 

You can also use an aux mix to create another mix for broadcast, a cry room or lobby or a board mix. In this case, you’d probably want to use a post-fade mix so it will track your mix. But you can add in more of the pastor’s mic and less of the band channels so it balances out better. While you can do this, I think there’s a better way, which leads me to…

Using Groups

If you only have groups and no VCAs on your console, you can use groups to control larger chunks of your inputs via a few faders. For example, you could set up a band group, a vocal group, a playback group and a speaking mic's group. So as you’re mixing, if you want to boost the vocals a little bit, you simply push that group up and all the vocals go up. Handy, right? There’s more!

You could also use the groups to turn the entire band off with one switch. Most times, groups will have a mute on them, so with a single button press, you mute the band. But there’s a catch; this will not typically mute the aux sends, so your monitors will still be hot. So you’ll still have to deal with that. 

In this case, we've used 4 of our Groups to split the band up into manageable chunks. Image courtesy of APB Dynasonics.

Another way to use groups is to break up your band into parts; drums and bass on 1, guitars on 2, keys on 3, vocals on 4, etc. Now you have a little more fine-grained control over the mix. To use either of these methods, you would simply assign the individual channels to the group you want, but not the L&R group. Next, assign the group masters to the L&R mix. This is kind of a poor man’s VCA approach. But wait, there’s more!

I use groups for a few things. The first is for parallel compression. I send my drum mic's (all 8 of them) to two groups, a normal drum group and a drum spank group. I do this to keep the processing paths the same length so everything stays in time. The normal group is unprocessed, but the drum spank group has a compressor on it. I compress the entire drum kit, then mix varying amounts of spank into my mix as the song requires. 

I occasionally do the same thing for vocals if we have a big event and multiple people will be doing lead parts. I’ll use snapshots to send them to the vocal smash group and mix that in. That way I don’t have to double-patch every potential lead vocalist. 

In the Aux section, I was talking about creating a broadcast or lobby feed. Here is another great use for groups. I have four groups set up and every input goes to one of them; band, vocals, speaking mic’s, playback. Those groups are combined in various levels in my matrix (which we’ll get to next time) for various outboard mixes. I have a lobby/cry room mix, a video mix, a board record mix, and a CD record mix. I’m not really using these groups to mix per se, because the relative levels of each input happens on the faders. But the groups are used for level-balancing. Because music is 20-30 dB louder than speech I add some more speech into my outbound mixes to keep the relative levels closer. I then have to compress those feeds less, which keeps everything sounding better. Clever, huh?

You can do more with groups, but we’ll stop there for now. Next time, we’ll wrap this up with some uses for VCAs and the Matrix.

Today's post is brought to you by GearTechs. Technology for Worship is what they do. Audio, video and lighting; if it's part of your worship service, and it has to do with technology, GearTechs can probably help. Great products, great advice, GearTechs.

CTA Classroom: Defining Auxes, Groups, VCAs & Matrixes Pt. 2

Last time, we looked at how Aux sends and Groups work. Today, we’ll tackle VCAs and most confusing off all, The Matrix (don’t worry—Keanu Reeves will not be making an appearance).

VCAs

When I first mixed on a console with VCAs I thought, “This is awesome! I never have to use groups again!” I was right. And I was wrong. The truth is VCAs and Groups, while they can be used to the same effect, are really two different animals, and both have their applications. Again, we’ll save the applications for later. Let’s figure out what a VCA is.

Image courtesy of APB Dynasonics.

Image courtesy of APB Dynasonics.

VCA is an abbreviation for Voltage Controlled Amplifier. Without getting super-technical, think of a VCA as a remote control for your fader. That might not seem very useful at first, considering you already have the fader right there. Where it gets fun is that you can assign multiple channels to a VCA, and you can assign a channel to multiple VCAs. More on that later.

Here’s how a VCA works (at least functionally—look it up if you want to know how they work electrically): Let’s say you have your lead vocal—channel 1—assigned to VCA 1. And let’s say you have channel 1 sitting at Unity level (sometimes known as 0). The fader is not adding or subtracting gain from the signal. If VCA 1 is also at Unity, there is no gain change. But turn VCA 1 down to -10, and the signal on channel 1 drops 10 dB, even though the fader hasn’t moved. Move the fader for channel 1 down to -10, and the signal is now down to -20 dB. If you leave the fader at -10, and put the VCA back to 0, the signal is at -10 dB. Push the VCA up to +10, and the signal is back to 0 dB. 

Later we’ll talk about why this is useful, but for now, that’s how they work. Digital consoles sometimes call these faders DCAs (for Digitally Controlled Amplifiers), or even Control Groups. No matter, they basically do the same thing. The important thing to remember is that VCAs aren’t better than groups; they’re different. I use both—to very different effects—every week. Given the choice, I would always have a healthy supply of both Groups and VCAs on my consoles (which is one reason I really like mixing on DiGiCo consoles…).

Matrix Mixes

The modern matrix mix can be a confusing beast. Back in the days of analog consoles, the matrix operated much like aux mixes do, but instead of being fed by individual channels, they were fed by groups. Thus, to create a matrix mix, you would assign your channels to groups, then build a matrix mix from your groups (including the L&R mix). Some mixers gave you a few matrix mixes, others gave you a lot. Matrix mixes are defined by how many inputs and outputs they have; to wit, a 16x12 matrix has 12 individual mixes being fed by 16 sources. On an analog desk, this would probably mean the console has 14 auxes plus L&R, and you can create 12 mixes of those groups.

Image courtesy of APB Dynasonics.

Today with the advent of digital consoles, there is no real reason why individual channels can’t also be fed into the matrix mixes. Some companies treat their Matrixes like Auxes (Yamaha & Roland for example). You can assign any or all channels to a matrix mix and use it just like another aux. The difference is, you can also assign auxes or the L&R mix to the matrix, so it’s really a hybrid. 

Other digital consoles let you assign groups to the matrix, plus a limited number of input channels. Still others let you pick a fixed number (say 16) of whatever inputs you want—input channels, auxes, groups, L&R—and mix them into 12 or so mixes. 

Matrix mixes can seem confusing, but hopefully once we get to the practical applications, it will start to make more sense. For now, know that they are incredibly useful for feeding ancillary rooms or destinations (recording for example), or even running your main PA depending on the complexity of your PA system.

So that sums up how each of these four mixing systems work. Next time, we’ll start unpacking how to use each of them. 

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