Gain Structure (i.e. gain staging)
In episode 0123 of the Worship Ministry Catalyst Podcast, we talked about some of the issues that plague worship ministries around the world. If you haven’t checked out that episode, you’re definitely going to want to do that!
What I wanted to do here is to just quickly explain the goal of gain structure for live sound. I specify live sound, because the principles aren’t necessarily the same.
I want to give you a heads-up, I’m a Worship Pastor who has learned sound techniques over my lifetime. What I say is what I’ve learned in that time, but it may not be what you would be taught by a pro.
The concept is pretty basic. At the top of your channel strip on your analog console there is a knob titled gain or trim. There may be other names for it, but on an analog board it will be the first know at the top of your channel strip. (A channel strip is the strip of knobs and/or faders that control that one channel.) The top is where the signal starts, at the gain knob. The bottom is where the signal is then sent out to your main speakers, at the fader.
On a digital board, the gain/trim knob will likely be found in a different location. Some digital boards still have the knob at the top of each channel, others have one knob and you have to select the channel to make changes. You’ll want to look at your manual to find it if you aren’t sure where it is.
Getting a good sound check is going to be extremely important when it comes to setting your gain. You’ll need the singer/instrument to play for you a their loudest and quietest they will be playing at during the service.
Just remember, it’s all about unity.
Just before we talk the how, one more word of caution. Some boards allow you to change whether your meters are showing you the input level or the output level (called pre or post metering). For setting gain, you want to make sure the meters are set to show you the actual input, which will be achieved by viewing the pre metering.
That said, when the singer/instrumentalists is playing at their loudest, make sure the meters are running right around, or slightly above zero or U for unity. I say slightly above because if you set it right at unity or just below, when they are playing quietly you may have to really crank the fader to hear them.
No matter the instrument, you’re going to want to set the gain to the same level. Another word of caution, the numbers on some digital boards are different than analog consoles. For instance, on the Yamaha M7CL the top number is zero. Obviously if you set your gain for zero, the channel is going to be pegged out. From my understanding, unity on that board is around -12 to -18. So, you’ll want to make sure to set your gain there. Look in your manual, or look it up on line, exactly where unity is for your specific console.
Problems if Gain is to low or quiet
If, you don’t get the signal loud enough, you’ll find yourself really pushing the faders on the console to get the instrument up in the mix. When you do that you can often add a lot of noise into the signal from the console or dirty power.
Problems if Gain is to high or loud
What can happen if gain is too high, is you’ll get a lot of clipping and/or distortion. You probably have a red light on the meter for each channel, make sure it’s not turning red. Even if you can’t hear the distortion, but the light is coming on, try to back it off a bit. It will add noise, and noise adds up.
What about when the signal has a wide dynamic range?
This is a topic for another post, but I’ll give you a heads up. If you aren’t running compressors in your system, that’s something you should definitely begin doing. This is exactly what compressors are for. Compressors help tame the really loud parts of an instrument which can help you bring up the overal volume. More about that later.
If you have any questions, leave a comment below.
If I have made a mistake in my explanation, please feel free to correct me below!
Hope this helps!