Hi there, I hope you are doing great. My name is Edison (The Sound Guy) and today we’ll be talking about a topic that every audio engineer or anyone in the field of music has come across and it is Gain Structure.
Are you in charge of the sound at your church, club or even an upcoming show? Have you ever felt like there wasn’t enough volume but the faders on your mixer were at max? Have your faders been all the way down but it still feels too loud? Well that’s why I got inspired to write this one
What is Gain?
It is a function in audio (hardware or software) that takes advantage of dynamic range of audio equipment. Dynamic range meaning the way signals vary between the noise floor and unwanted distortion. Think of it as the range between leaves falling from a tree to the sound of two helicopters flying over your house.
Noise Floor – All audio equipment adds noise to the signals coming into your mixing consoles, it’s usually really quiet but if the signal coming in is also quiet then the noise can be heard. The solution is to make the wanted signal louder relative to the noise floor.
Distortion (When the mixer levels hit Red) – When louder signals exceed the upper range of the audio equipment, distortion occurs. The solution is to keep the signal below the circuitry’s (of the mixer or DAW) clipping point.
Application in Live Mixing
The Gain/Trim/Pre control can be found at the top of each channel in Analog mixers. In Digital mixers it can be found in the Pre-Amp / Configuration / Overview sections. Each channel has one. On some Yamaha mixers it’s called H.A (Head Amp). This controls the pre-amp (small amplifier) to add gain to amplify small incoming mic level signals and reduce/trim line level signals.
Here are a few steps to help when setting gain while mixing:
- Get the signal going in the channel. You can’t establish correct gain levels if nothing is happening. Make sure when you’re doing sound check that the singer is singing through the microphone or the musician is playing their instrument.
- Press the PFL/Solo button for the channel. This helps you increase or reduce the signal coming in without guessing. Make it dance around 0 (Zero) which is the sweet point. At this point the colors in the meter are Green with the loudest parts going into the color Amber (light orange) which is okay. If they hit Red that means the signal is too loud.
- In digital consoles it’s different 0 (Zero) is the loudest. So all signals at this point will be distorting. Everything below Zero will be in negatives which is okay. Usually the sweet point depending on the digital mixer is -12 or -14 or -20 dBfs just below amber.
Myths about Gain
- Gain causes Feedback (The annoying ringing).
This is far from the truth. Even though hot signals through the speakers contribute to feedback, feedback can be controlled by other methods but Gain is not the cause. I shall expand on this in my next article. - Gain is set once.
Always remember that the sound check is totally different from the actual performance. The artists bring in more energy during the performance. So be sensitive to all Gain levels even as the performance happens.
What has your experience been like concerning Gain? What questions do you have? Please comment on the Talking Audio Facebook page. See you in the next article.
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Ediversion 