Live Sound Notes #2:
Gain Staging and Signal Processing

Umut Yelbaşı

06 October 2025

I finished a three-year Bachelor's degree as well as a Master's degree, and did a fair share of live sound events in different capacities, but every single time I worked at a gig I learned something I hadn't heard before. Learning genuinely never stops in sound engineering, partly because technology is always evolving, but mostly because there are so many things you can do in so many different ways, and a few things you have to do in a specific way because of physics or standards — like proper gain staging, impedance matching, or electrical safety. And I feel like everyone could use a memory refresh once in a while.

To help myself remember things and to maybe, hopefully, help other sound engineers in the beginning of their careers, I started this Live Sound Notes series where I will be going through concepts I've come across during my experiences. You can read the first chapter on Signal Path, Cables and Connections by clicking here.

What Is Gain Staging?

Nick Messitte, writing for iZotope, explains it well in his article: "Gain staging is the process of making sure the audio is set to an optimal level for the next processor in the chain in order to minimize noise and distortion."

The article is on recording and music production, but the principle is the same in live sound. You want your input signal, the signal that you'll use with processing elements in your signal chain, to be at the most optimal level possible (not too quite, not too loud). This is to prevent excessive noise, or in other, maybe more familiar words, to maintain an optimal signal-to-noise ratio without unwanted distortion.

Doing this at the input level helps your mixing process tremendously, giving you a more controllable, predictable level that you can work with, and getting it wrong will cause you lots of problems later on.

Input Gain Control

Almost all mixing desks you'll encounter will have an input gain knob. When you're beginning the sound check of a channel, start with this knob, and bring your channel fader all the way down. The input gain knob controls the initial amplification of an audio source (a microphone, a line input, etc).

Remember that you aren't listening yet, you're getting your signal right so when you do start listening, you're listening to (and manipulating) an optimal signal.

At this point, you'll have to ask your artist to play their instrument or sing as loud as they would during their performance. While keeping an eye on your input level meter, start adding input gain to your signal through the input gain knob. You want the signal to peak right below the yellow (red if there is no yellow), or at 0. Below is an example of how these signal levels might look.

In digital desks, you will almost always get a separate, digital meter that's directly connected to your input gain knob (which might also be digital, or a virtual knob that you have select before using one of the physical, general use knobs on the desk). Regardless of how the meter looks, what you're looking for at this step is the same: the input signal to reach zero when your artist is playing the loudest, and not hitting the red/yellow.

Setting Up the Rest of the Chain

Once your input gain is set, your signal will go through processing units like your desk's EQ, compressor, etc. Each of these units form additional gain stages, which means with the effect they have on the signal, the signal level you set before will also change.

The goal is to maintain healthy levels through every stage, preserve headroom, minimise noise, and avoid overload.

Keeping in mind that 1) each desk might have a different processing order (which is completely fine), 2) some desks may have units that others don't, and 3) you might have outboard gear that you use for processing, here's how to think about and manage each segment in the chain:

The Channel Strip: EQ

An EQ is essentially a gain controller for specific frequencies. It works by adding gain to (boosting) or subtracting gain from (cutting) selected frequencies. This is important to note as, even though EQ is also used as a creative sound shaping tool, excessive boosting can push a perfectly good input signal into clipping after the EQ stage.

Once you make your EQ adjustments, re-check your channel's output meter. If your adjustments boosted your signal into yellow or red (see meter graphic above), you will need to reduce the EQ boosts you've applied, either from the specific adjustments or from an overall "EQ gain" adjustment knob/fader.

The number of topics I could cover in live sound is unbelievably high, but I want to keep these notes bite-sized and straightforward, so each article will focus on a few core concepts at a time.

Next in the series, I’ll cover gain staging, a crucial concept for maintaining a healthy signal-to-noise ratio throughout your system. Proper gain staging helps your microphones, instruments, and DI boxes perform at their best and ensures your final mix is balanced and clear.

The Channel Strip: Dynamics (Compressors/Gates)

This is arguably the most common step after the preamp where good gain staging falls apart.