As noted lots of ways to get there.
How you get there and control that mic channel depends somewhat on if you set it up
to be on a pre fade or post fade aux send.
Let talk post fade for now, that way you can have the mixer in the main LR mix layer
to control the other inputs and the room mic channel.
– Select the aux you want to use.
– In that aux set up menu select post fade and I would also select post all for the
aux pick off point.
– Go to the routing menu.
– Select the room mic channel by hitting the green select button.
– In the routing menu turn off the LR main mix select button.
(you can also do that by selecting the main LR mix on the mixer surface and
then hold down the assign button on the left side of the mixer. Doing that
will light up all the channel select buttons that are routed to the selected mix.
While holding down the assign button hit the green select button on the room mic
channel, that will turn off the select button light and de-select it from the
main mix.)
– Now select the mix/aux you want the room mic to go to.
– Bring up the mix master level and on just the channel for the room mic
bring up the fader, start and unity about 75%.
– Select the LR main mix on the mixer surface
– With the room mic channel set for post fade and de-selected from the main LR output
you can control the room mic level feeding the aux from the main mix layer on mixer.