I would then either turn the midrange section down on the mixing board, or I would select 440Hz on the frequency selection knob, then turn down the level control for that frequency. Route the signal. The bottom of the channel strip offers another option for routing signals. On most mixing boards, you can choose left or right signals as well as subgroups. By selecting the right buttons, you can assign sound to travel right to the main output of the mixer or through a subgroup.
Subgroups are good for controlling the volume of multiple inputs.
For example, you could assign the worship leader's microphone to the main mix and the background vocalists' mics to a subgroup. This will allow you to bring the total level of all the background mics up or down with one fader. Check your soundboard's operating manual to see whether this is how your mute button works. Regardless, the mute button will affect a channel in the subgroup as well as the main mix. This is very handy for cueing up tapes.