One of the more common audio mistakes we see in churches is improper setting of input gain levels on the house mixer. Getting input gain right is one of the most critical steps in creating good audio mixes.
Setting the input gain affects absolutely everything we do on the console and it can make or break your house mix, monitor mix, recording mix, etc. Before we start mixing the house on the channel faders or do anything else, every channel’s input gain should be dialed in.
A Simple Analogy
Think of your audio channel as a garden hose, and the gain knob (a.k.a., trim or HA/head amp knob) as the water spigot. If we were going to fill up a bucket, there is an ideal amount to open the spigot.
Opening it up too little means we get very little water and while it works, it takes a while to fill the bucket and is not terribly effective. Opening it up too much often means it’s going to get messy with water going everywhere.
This concept holds true with audio. Too little gain will give us weak, inefficient sound. It’s not that there isn’t sound, but it doesn’t sound big and full as we’d typically like things to sound. Overcompensating on the input gain to get your weak level back up to where it should be also introduces unpleasant noise into the system.
We also make a mess when we turn our gain up too much. Pushing too much signal through causes clipping—not a pretty sound!
How Do I Know When Gains Are Set Right?
Unfortunately it’s a little different on every console, but there is a pretty easy indicator that you can use to find the sweet spot. On most consoles, analog or digital, you usually find an input meter—or at the least a little level indicator light.
On the meter, you usually see three different colored sections: green, yellow and red. Even if you have a single light, typically it’ll show green if you have signal, yellow if you’re getting a lot of signal and red if you’re getting too much.
On most consoles, a great target for your gain is right where the green and the yellow lights meet. On many consoles that’s the number 0 on the meter, or 0 dB. For others it’s a different number (for example, on Yamaha digital consoles this happens around -18 dB).
Regardless of the number, setting your gain to where the green light meets the yellow light should give you a big, full sound with plenty of head room to avoid clipping.
Remember, the first thing you need to do is set input gains before anything else. In fact, my ideal way to do begin sound check is to have the band run through 1-2 minutes of the biggest song on their list for that week.
You could do each instrument individually, but in order to save time and verify that the band and singers are giving me their full effort, I’ve found that having them run through something big for two minutes is enough time for me to quickly move through each channel and set gains accordingly. I don’t touch anything else in this period of time—in that 120 seconds I’m only looking at gain, making sure every channel is giving me enough and not too much.
Once completed, all house volume changes are made at the fader and monitor mix changes are done at the auxiliary (AUX) knobs.
Don’t Touch That Dial
Once I feel good about my gain, I do my very best to not touch it again. Sometimes someone jumps all over his/her mic or instrument and you have to decrease your gain a bit, but if at all possible I leave the gain alone at this point and just adjust their fader to change the house sound.
Why? If I adjust the gain at this point, I change the house mix, monitor mixes, recording mixes and everything else on the console. At that point I’ve also taken away the musician’s reference point. What she thinks was ground zero for her volume is no longer true. As she tries to play dynamically, she no longer knows whether he can trust what he is hearing.
We want big, full sound from our instruments and vocals in order to produce a good mix. Our musicians need consistency in their monitor mixes in order to be comfortable and know what they are playing is translating well in the mix. We want our live recordings and web/broadcast feeds to have good consistent sound.
All of these things are affected by how we set the input gains on our house mixer. We need to get our input gains set right at the beginning of the sound check by setting levels close to 0 dB, or between the green and yellow signal lights on our mixer. Once we get the gains set, we leave them alone to keep mains, monitor, recordings, etc., consistent.
Take the time to get you’re gain right, it’ll change your mix for the better!
Duke DeJong has more than 12 years of experience as a technical artist, trainer and collaborator for ministries. CCI Solutions is a leading source for AV and lighting equipment, also providing system design and contracting as well as acoustic consulting. Find out more here.