My mixer is in a closed booth at the rear of the theater. We've got a window and good monitor speakers which make mixing tolerable. But I would like to put in an SPL meter with a read out in the booth and a mic located out mid-house so we get an idea of how loud it is out there. I'm not sure the best way to go about this. Suggestions for an SPL meter with the mic located 40' away from the read out?