That question seems like it should have an obvious answer, right? Unfortunately, that's not always the case.
For years, we've debated with architects, church building committees and just about everyone else (except the sound technician) when it comes to choosing the location for the sound booth. Sound technicians know where the sound system controls need to be, but because even building design experts don't "get it," your sound technician is very likely listening from the worst seat in the house. That doesn't make much sense, does it?
Rule #1 - when picking a location for your sound booth, make sure that the sound quality and general volume level at the sound booth is the same as it is in the sanctuary itself.
Rule #2 - forget any other ideas that you have.
It's just about that simple.
I can't tell you how many times I've visited a church only to find the sound system controls in an unused balcony, against the back wall in a corner, enclosed in "control room" with a window, in its own little cubbyhole "out of the way" or even completely outside the sanctuary itself. Think about it. If you expect good sound (and all of us do), make sure that you don't make the mistake of putting your sound technician someplace that he or she can't hear well.
Unused balconies may make convenient and semi-secure locations, but if your sound technician has to run up and down the stairs to make sure that things sound good for the rest of the congregtion, doesn't it make sense that he or she shouldn't be there in the first place?
Bass frequencies build up against walls and in corners. If you wonder why the system sounds "thin" in most of the auditorium, it's probably because the sound technician hears more bass where he or she is sitting due to the nearby walls.
Please don't put your sound technician in a "control room." Yes, it's secure, but your sound technician needs to be a part of the worship service in order to participate, to keep from being distracted, and to hear what the rest of the congregation hears. I've even been to churches where the system controls are outside the sanctuary entirely. Think about that. How can anyone possibly control the sound for a room that they're not physically inside?
Effective sound system operation is the key to having a "successful" worship service. If your sound technicians are asking to be moved into the main sanctuary, away from the back wall, out of a "control room" that the architect designed, or any other suggestion, please listen. Getting God's message to your congregation depends on your tech team being equipped to do its job well.