Do I mix with the faders or the gain knobs?

I have had lots of people ask me how to properly set the levels on a mixer. The critical step of proper gain staging is often missed by newcomers to the live sound realm.

Obviously there will be some difference from mixer to mixer depending on what mixer you have. Some mixers have a gain at the beginning of each channel strip and some do not. Several of your standard box mixers do not have channel gain. You simply have individual channel volume and master volume output. Though this is easier for most people it can sometimes be messy to.

The basis behind pre channel gain is so that the signal coming in from the microphone can be set at a level which the mixer can handle without distortion from the signal being to hot or from noise from the signal being to low. One of the common terms used for setting the level is unity. Unity (0 cut or boost) means that the level coming into the channel is the same level that is leaving. So if the gain at the beginning of the channel is unity, and the channel volume is unity, the signal passes through without changing.

What if we have a condenser microphone that has a very strong signal on one channel and dynamic microphone that has a lower signal on another channel? I would want to be able to mix my channel faders around the unity (0db) range so that I have the same levels across my mixer. I would set the channel gains to compensate for that difference between the two microphones at the channel gain and I would have the same level from both microphones at the channel faders. That way your job is easier when you work your magic during the show.

You must also consider that the equalizer settings in the channel affect the gain as well. If you set the gain and then you adjust the equalizer on that channel, the outcome will be a change in gain at the fader of the channel. This is more common with music sources (CD/CASS/DVD) that are fed into a channel. Lot’s of people will tend to boost the lows (bass) on a channel. This will most certainly overdrive the channel unless you turn down the input gain.

Luckily, lots of current desk mixers have a great little friend called PFL (Pre Fade Level). This is a great tool for setting your channel gain. If you have your favorite guitar player play his guitar, you can hit the PFL button and shazamm, the level shows on your master level meter. You then adjust the gain until the meter peaks just above the 0db led. Then just rinse and repeat on the other channels.

Oh Ya, the question, do I mix with the gains or the faders? Absolutely never mix with the gain knobs! Always set your gains first and then mix with the faders. Keep in mind that if you are running monitors on stage, the gain will affect those also. Faders do not affect monitor levels.

Happy Mixing and hope to hear you around.