I've been really busy recently and distracted from this project, but thought that I should provide an update. If you're familiar with the term "askhole" I'm trying to avoide it applying to me.
I did call the local professional and got a quote ($400) for coming out and doing a full setup. He also recommended that we consider a Symetrix Jupiter 4 ($1,000) for our application. We had a long discussion about how the monitors, under balcony speakers, and main speakers all needed to have a different EQ to achieve the best results.
At this point I'm working with the rest of the AV Team to evaluate our options. I know that the Church Board would approve the $1,400 (because they trust us) so it's important that the AV Team have consensus on the best solution. My personal feeling is that I would prefer to have something with more flexibility than the Dx38 if we are going to spend the money to have a professional setup done. I think I may have to contact the person that previously helped setup the system in my church originally to see if he still has the equipment and willingness to help. I am not sure what his level of skill really is, but it shouldn't cost anything to find out.
I'll take another look at the Sabine GraphiQ.
Thanks again for the ideas and information.
I spent about 12 years running live sound in a church that had a very dated design that lacked many of the architectural features that tend to reduce a room's susceptibility to feedback. Heck, about half of the main speaker cluster was almost boresighted on the area that eventually became our band/orchestra pit, and that is just an example. Of course the church board was stagnant on many more pressing issues, so the sound system never received serious attention, either.
However I was able to sneak in a little technology both in terms of mics and electronics, and my tour of duty was characterized by other experienced mixers from larger churches in the area including some of my predecessors as being generally clear, well balanced and pleasant.
After looking at the DX38 it does not seem to lack the sum and substance of the electronic tools that I used to do what I did. What it does seem to lack is an easy user-oriented interface.
The idea of augmenting a well-adjusted and locked down DX 38 with something that has easy-to-twirl knobs has a lot of romance.
I will fearlessly countermand those who recommend against parametric eq. I've used both graphic and parametric eq, and if there are enough bands a graphic eq can work. But given the choice, I'd pick a multiband parametric first, just about every day of the week. 4 bands minimum, 6 wouldn't be wasted.
Live sound systems being necessarily dynamic in these days, adaptability. Electronic approaches to feedback reduction are necessarily intimately tied to a certain configuration of microphones. Move one several feet or even reorient it, and its time to retune the notches.
The best antifeedback tool is an experienced operator with the appropriate tools. This includes both equalizers and a collection of mics and stands and knowledge about how and motivation to use them. From the standpoint of the mixing console, the most effective tool is muting the mics that aren't relevant to the current scene.