Gain is not volume
Gain (also called trim or preamp) amplifies the microphone or instrument signal as it enters the console. The fader controls the level at which that channel is added to the mix. They are two different controls with two different jobs.
- Gain too low: the signal is weak and gets noisy when you raise it afterwards.
- Gain too high: the signal clips (distortion) and cannot be repaired.
How to set it, step by step
- With the channel fader down, ask the person or instrument to play as in the service (sing loudly, play with force).
- Watch the channel meter. Raise the gain until the signal is strong, with peaks that do not reach red. A common reference on digital consoles is an average level around −18 dBFS with peaks below −6 dBFS.
- If the meter turns red (“clip”), lower the gain. If the instrument is still too loud, use the channel pad (attenuator).
- Now raise the fader and build the mix balance.
Practical tips
- Set it with the real source: do not set gain with someone speaking quietly at the check if they will sing loudly later.
- Use PFL/Solo to listen to and see the isolated channel.
- Fader near the reference point (0 dB or “unity”): if you need the fader very high or very low, the gain is probably not right.
- Phantom power (+48 V): switch it on only for channels with condenser microphones or DI boxes that need it, and with the channel muted when you do.
- Write down the gains that work (or save them in a scene) for the next service, but always check them: every person and every microphone changes.
Common mistakes
- Leaving the gain low “just in case” and pushing everything with the fader: the mix has no headroom and gets noisy.
- Setting gain only with the microphone close to the mouth at rehearsal, then performing farther away in the service.
- Not checking when the microphone or the singer changes.