When it comes to live sound, input gain is one of those things you have to get right. If your gain structure is wrong, no amount of EQ, compression or fancy plug-ins will fix it. Over the years, I’ve seen my share of gain disasters, and have found many who simply don’t know how to properly gain stage their console.
In this short series, I’m going to give you two ways to set up your gain, plus a hybrid approach (the .5). There a few schools of thought on how to set gain, and it’s hard to say that one is “right;” it really depends on many factors. There are some wrong ways to do it, however, and we’ll get to those in a moment. First, let’s define input gain.
Input Gain is the gain applied by the console to mic and line level inputs coming into the each channel. Most consoles have a gain knob at the top of the channel strip labeled “Gain,” “Input Level,” or sometimes confusingly, “Trim.” The knob controls how much gain is applied to the microphone preamp, which is necessary to bring the level up from the lower mic level to the working level inside the console. Things are a little different for line-level inputs, and for clarity’s sake, we’ll focus on mic inputs for now.
How Not To Set Gain
Running your input gain way too high will generally result in distortion. There are a few consoles—typically expensive analog ones—that will handle overdriven mic preamps with grace, and even sound good. But generally, you want to avoid lighting up the peak, overload or clipping lights. This is especially true with digital consoles.
You can usually tell the input gain is set too high on your console if you find yourself running all your faders below −20, and the master is also turned way down. It will also sound bad. That should be the first clue, in fact.
Over the next few posts, I’ll unpack these two methods and then give you my method which is sort of a combination between the two based on my available equipment. So next time, we’ll look at Faders at Unity.