Obviously, this isn’t about Gain, the detergent. However, the proper use of gain will give you cleaner signals with less noise.
The word gain is usually associated with your sound board in regards to setting the gain level. Using the gain knob on a particular channel, you are increasing the input volume of the incoming signal. This is sometimes known as the trim knob. The word gain refers to electrical gain. Electrical gain is the difference between the input signal level and the output signal level. It’s measured in decibels.
There is another place gain is important outside of your sound board. As different electrical components are chained together and a signal is passed from one component to another, there are times when gain must be applied so the final output signal is within the decibel range that is required.
For example, a guitarist can have his electric guitar hooked into his amplifier which is then hooked into the church sound system via an XLR cable, usually via a DI box. The volume coming from the church speakers is controlled in three places; the electric guitar’s volume knob, the amplifier’s volume knob, and the sound board channel fader.
The mistake is thinking you take all the gain via the sound board’s gain knob. Whenever you increase the gain, you are also increasing the volume of all the noise associated with that sound signal. The more stages between the original source and the output, the more noise that can be introduced into the system.
Using the guitar example, the guitarist should turn up the amplifier so that you only require a nominal amount of gain for that particular channel on the sound board. If you have the gain on the channel set to zero and you are still getting sound from the amplifier, have the guitarist turn the amplifier down.
I did not mention altering the volume knob on the electric guitar. Guitarists are very picky about their tone and the volume from their guitar into their amp can affect their guitar’s tone.
Whether it’s a bass amp, guitar amp, iPod, or any other input source, take the gain as early as possible. This will result in a cleaner sound as less noise is present in the output signal.
Quaid says
March 29, 2012 at 9:18 pmThe concept of good gain sturcture is, simply, to avoid distortion, and minimize noise.
With that being said, I have some grips about working with, and/or explaining proper gain structure to, people who don’t understand it:
1) People who want to use a pad on their mics, then compensate for the pad by turning up the gain on the board.
My approach with a pad: if the input is clipped, when the board’s channel gain is all the way down, THEN use your pad. Not untill, cause it will degrade the signal-to-noise ratio.
2) Singers who have labtops with backing tracks, who will not give you their hottest output during soundcheck. But they will “mix it” during preformance, instead of letting YOU, the operator, give a good level to them before preformance.
3) People who want to turn up the power amplifier’s gain all the way. ( BIG GRIPE! )
Then they want to run the main mix faders near the -20 dB mark.
If you can actually leave the power amp at “0” or not depends on many things, including the board’s maximum output level, ( is it + 18 dBu? +21, 22, 26, 28, 34 ? You get the idea.)
the maximum input and output level of any processing devices set up after the mixer, level changes through the processing, (are you boosting alot on your graphic eq, cutting outputs levels on your active crossover, ect.) and the amplifier(s)’s input sensitivity. (0.775 Volts, 5 Volts, or another value)
Any tinkering someone does could very well, if the soundman isn’t “on the ball”, ruin a preformance.