I guess I need to read up on the high pass filter. I've seen them but not sure what they do.
HPFs are basically a mud stopper, cutting low frequencies below a certain frequency that are not needed that just mud up the subs. This helps to bring focus and clarity to everything above.
The question is, at what frequency do you want to cut. When I've played outdoors, I used the standard HPF on my Crest Prolite amp of 50 Hz. Worked wonderfully.
Churches with subs typically run whatever you give them. You might consider cutting at 30 Hz or 40 Hz depending if you use 5s or 4s with standard tuning.
That's the theory anyhow. I need to get a HPF for my church board ...