Good grouping practices are key to getting a mix together quickly and, at the same time, allowing you to make refined and controlled movements during mixing.
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Two Key Grouping Styles
While there are many new and exciting styles of groups coming online with the outbreak of digital live sound consoles, for the purposes of this article, I’m only going to concentrate on two styles: “audio sub groups” and “VCA groups.”
Given that the vast majority of consoles, analog or digital, offer these two styles of groups, I strongly encourage you to thoroughly understand the differences between them and work toward using them.
While many mix engineers tend to use one or the other, they are certainly not mutually exclusive of one another, and when used correctly and together, are a very powerful tool.
Let’s start with audio sub groups. Audio sub groups are generally either mono or stereo and, by definition, provide a summing point for a given number of inputs before they then head off to the left/right master output.
This means that any number of audio inputs can be directed through the audio sub group and the group as a whole can then be moved up or down in volume. By soloing an audio sub group, and listening in headphones, you can then monitor the fader balances of all inputs that are feeding the group, including their pan position.
For example, with the push of the group solo button on a drums group you could listen to the relative blend of all the drum mics and, in turn, affect the overall level of the drum kit in the PA system by moving the group fader without having to change the input fader positions.
The input faders would still be feeding any post-fader aux busses even though the audio sub group fader would be at zero.
Additionally, because audio is actually passing through the group, it will usually offer an insert point where you can patch in equalizers or compressors and limiters which, of course, would affect the drum mix as a whole in the PA system.
This is where the difference between audio sub groups and VCA groups comes to light.
A Voltage Controlled Amplifier (VCA) does not offer an actual audio path for the inputs assigned to it. Instead, once a number of inputs are assigned to the VCA fader, it essentially works as remote control of the assigned faders.
For example, if you had a blend of eight input faders and you assigned them all to a VCA group, once you move the VCA group fader down, it is exactly as if you simply reached over and pulled the actual input faders down.