The Essence and Importance of Soundchecking
The sound check process is the one of the important parts of your stage work. The purpose of the sound check is ensuring the right sounds get to the sound booth, to the monitors, and to the house speakers.
The first step of the sound check is called a line check. During this process, the sound tech verifies that all of the equipment on the stage is sending a signal to the mixer. They will verify each instrument/vocal one at a time. This process requires all members on the stage to be quiet when it's not your turn.
The second step is setting your volume. Technically speaking, the sound tech sets what is called the gain structure of each instrument/voice. The sound tech can do this either one by one or while your band is playing. Once this process is complete, they will have a rough volume setting for you but it's not totally indicative of the final mix so don't think too much as to how it sounds in the house mix.
The third step is setting monitor volumes.
In the case of in-ear monitors: you may set these on your own, but only after step 2 is completed as gain change from the board will alter the volume level in the in-ear systems dramatically. A gain change when you have your in-ears in could cause temporary or even permanent hearing damage.
In the case of spot monitors / floor monitors: the sound tech will work with each person one at a time. Point to the musician you need in your monitor and then give the sound guy the up/down/ok signal.
The fourth step is simple – just play.
At this point, you should at least play one or two songs that are to be played during showtime. During this time, the sound tech will tweak your sounds as necessary through the use of EQ and other effects. This is a crucial time for them to get your sound right.
You might see your sound tech walking randomly around the room at some point. Don't think they have finally cracked. They are checking how the mix sounds in different parts of the room. The dynamics of the room play a part in how they mix the music. They might also have to turn down your overall monitor volume if it's negatively affecting the sound in the house. If they do this and you can't hear a particular sound any more, talk with them about the issue and see what can be done to rectify the situation.
One final note on the sound check process, when you play songs for the sound tech to set a good mix, play songs you know well and don't stop and start. It's not the time to start discussing arrangement changes with the band. Save that for later during practice if you have to do it at all.