Nunio,

Well, that's one mistake you'll never make again!


Good idea to make some time and get everything working as you expect.
Next time, perhaps you could ask someone to go around and gently tap on each mic, so you can see the meters moving for each channel individually.

I do this when I've set up a stage. I carry an iPad so I can see what's going on, and then check each mic in channel order.
It's better to catch something not-working this way, rather than when the musicians are on-stage waiting for you.


Chris