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"Helping You Sound Your Best"

Jordan Audio Consultants
GAINING UNDERSTANDING: The Proper Use Of The Gain Control


   
The first circuit in the console that the source signal "sees", is the preamp. It will always be the first adjustment. Since the preamp feeds to all other signal chains, this first circuit adjustment must be set correctly for every device connected to the console. This will insure a low noise-level while remaining free of distortion.

    The control that varies the level of the signal being sent into the preamp is labeled: gain, trim, input sensitivity, or attenuator. These are all words for the same control. (We will call it gain.) If the gain is set too low, than all other parts of the signal chain must be set higher to compensate. The result is the addition of unnecessary noise. If the gain is set too high than the input signal could overdrive the preamp and clip the signal and induce distortion. Neither of these is desirable.

    Gain could be thought of as a window. At the top of the window is distortion, clipping, peaking. At the bottom of the window is noise, hiss, static. We do not want to let the signal get into the distortion. We also do not want to let the signal get buried in the noise. What we want is for the signal to fluctuate freely within the window.

    The proper setting of this control will vary with each microphone, and user. This is because each mic has a slightly different output level and each user has a slightly different volume level into the microphone. This is not a problem since this is exactly the purpose of a gain control. The same holds true for line input sources such as tape decks, wireless mics, keyboards, etc...

    Once all the input gains have been set, the channel faders will have a nominal starting point. Of course throughout an event the individual fader locations will change to compensate for the artistic needs of the mix, but the gain settings will remain constant unless the primary use of the input source (mic, tape, etc...) changes.

    The following is a step by step check list for setting the console gain on a properly calibrated sound system.
         - The first step is to see that all connections and routing assignments are properly made.
        - With the gain levels turned down, (full counter clockwise) have the performer begin singing or playing.
        - Bring the console master fader and/or sub group fader to their nominal position (usually "0" or "-10" dB.)
        - Bring the channel fader to the nominal position ( usually "0" or "-10" dB)
        - Slowly begin increasing the gain until the volume level through the main speaker system is appropriate for the performance.
        - Next bring the monitor levels to their nominal position ( this may be difficult to determine if the system is not properly calibrated.) This will be a clean and appropriate starting place for the monitor systems (adjust as needed by the performer.)
        - Make any necessary eq and reverb adjustments for the most natural sound.
        - Now you have a clean, undistorted and appropriately leveled natural sounding signal you can mix for an outstanding performance.

    If you will follow this procedure at the beginning of every rehearsal session, you will have a better blend, happier musicians, and usually a faster sound check. It also lets everyone know that you take your job seriously. (You're not just foolin' around back there.)

    If you do not follow this procedure you will not know exactly how loud any one source is in relation to the other sources and the monitor mix can easily be "whacked out." Don't worry though, the folks on stage will let you know when their mix is not just right.

1998 Jordan Audio Consultants