Thread: Gain vs Fader

The gain controls the level out of the preamp.

On most boards, the GAIN is, essentially the "sensitivity"of the INPUT stage of the channel. The fader sets the OUTPUT of the channel feeding the various busses subsequent to the input preamp.
The reason there are (2) "volume" controls (your friend's terminology, not mine!) is so that you may "match" the level of the source to the "nominal" operating level of the preamp circuitry it's "hitting". For example: You stick an SM-57 into the front of a roaring Marshall amp.
That 90dB+ sound pressure level is going to generate a very strong output voltage from the mic to your channel input. Now that channel input has to be flexible enough to handle not only that signal, but, say the female back-up singer (say, 10-15dB quieter) on a 58. The GAIN control lets you adjust the amp mic DOWN to prevent overloading the preamp (which would cause massive distortion), and adjust the singers' channel UP to get the signal over the residual noise level of the preamp. That's why they have those little red LEDs on the channel-to let you know the signal needs to be turned down at the preamp gain. If you have an additionl green LED, it's usually used to let you know when to turn that Gain control UP.
Once you have that Gain control set at the proper level, you use the fader to MIX the channels, and that position of it should be somewhere approx 2/3 up on its travel, but that depends on the design of the board. Basically, if you are getting enough signal in the mix while the fader is barely "up", you are probably running the Gain control too "hot". and vice-versa: if you are pushing the fader to the max, you are setting the others incorrectly. This is what is referred to as "gain staging"and is mandatory to learn to correctly operate an audio mixer. Capiche?

Tell him that the gain is the water main for a house. The fader is your water faucet's. Simple.

Great analogy, Sheet! Does that mean that the comode is the monitor send? ( I know of a couple of IEMs I'd like to flush...)

Sheet -> I have been thinking about your water main analagy and as there are many gain controls for each channel on a mixer whereas there is generally only 1 water main for a property, I would probably describe the water main as the two main left+right faders that control the output from the mixer if you were looking at it from the output in?

Good points.

Other thing is that it gives you better control. You adjust the gain to give you optimal trough put when the fader is in possition Unity gain.
When thats done you have full control. you know that if the fader is at Unity gain its as high as it goes before peak.
Without a proper gain adjustment the fader handlig would be messy.
The signal would maybe only fit in a small specter of the fader.

It's hard for me to put it to words in english :D

This is precisely the problem I have too! :?

I know how they both work but you just can't explain it easily in plain English!

As you say HansAM - You set the fader to unity (0dB) and then the gain is adjusted so that the level is just below peak.

That works on some makes of boards, but certainly not all. Some boards don't have "unity" until the faders are maxed out. Others the faders are a real gain stage early in their travel. On many mixers, the EQ will have a say in where the Gain control at the front end is set. Realistically, the fader position shouldn't dictate how the Gain control is set. The source does that.