Have you ever wondered why your mixing console had a loud hiss? Or maybe your faders were too low and weren’t reflecting the overall volume of what was coming out the PA speakers, or the system just sounded “bad”? The list of questions can go on, but I ask because these are just a few examples of improper gain settings throughout the sound system. One of the most important things you can do to make your audio sound system sound amazing, is to set up the gain structure properly.
Let’s start by defining “Gain Structure”. Gain structure is a term used for the collection of multiple gain adjustments throughout the audio system such as, the mic pre, the fader, the master output level, the input gain of the amplifier and so on. Our job is to get these all working well with each other. There are plenty of ways to do this, and you can find several articles on the web, specifically on Gain Staging and Gain structure processes, but today I will share one that works well for me.
When I can, I like to start with:
- Amp Control Levels in the down position
- Amps powered off
- All gains throughout the “Audio Chain” in minimum gain position
- Bypass All Compression, EQS on channels and on the outputs.
Then I proceed w/ the Mixing Console. The “Signal flow” is important to know. Most consoles have the following order: Head Amp (HA) / Gain> EQ> Compression> Fader> Master/Main Out (Sometime Sub Outs or Aux Out).
- Make sure Microphone/ Source is active and feeding the input of the console.
- Start with Faders at “Unity” or “U” or “0” (Including the Master Fader. Amps should still be off)
- Next I will turn the “Gain or Head Amp” up until I reach a desirable input level close to clipping. I like leaving headroom so I get it to clip and back down from there. It’s best to “live” in the “yellow” and occasionally “kissing” the red depending on the source. (My reading on my Master Output should be at its max before clipping)
- Now, time to make some noise! Turn On Amplifiers (make sure knobs are all the way down!!!)
- Turn up the amplifier with mixing console outputting at almost clipping signal, this will ensure us that the mixer is providing the AMP the MAX amount of voltage. In this stage we are turning up the “Sensitivity Knobs” on the amplifiers close to Clipping and that will ensure us that we are optimizing the amplifiers power
What we did here throughout the chain was maximize the signal to noise ratio through understanding Gain Structure and Gain Staging! This is one of the many approaches I take. I recommend understanding the following terms and then attempting the above steps on your next GIG! Let us know how this works for you and I’d also love to hear your approach on optimizing your system and achieving a great sounding audio system!
Some Terms Worth Knowing:
- Gain Staging
- Gain Structure
- Signal to Noise Ratio
- Dynamic range
- Head Amp or Gain