I have two rows of 3 seats and the subwoofer is in the left front corner. Using Quick Measure at every seat, I found that each seat on the right side of the room had SEVERE nulls from 60Hz and up (basically, after 60Hz it looked like a sheer cliff drop-off). The middle and left seats had pretty normal small peaks/nulls.
When I run ARC, I normally use my boom mic stand to place the microphone in the middle of each seat at ear height, so I have six total measurements. Here is the ARC results of using my normal six measurement spots showing I still have bad nulls from 60Hz on up causing ARC to use 80Hz for the LFE LPF setting:
Here is the same graph with me manually setting the LFE LPF to 120Hz:
Now, here is where the hours of Quick Measure paid off. The following graph is using new measurement spots (front row middle seat, front row between left and middle seat, front row between right and middle seat, back row between left and middle seat, and back row between right and middle seat):
Now, as you can see, ARC still set the LFE LPF to 80Hz (as the 80Hz setting had a near perfect Flat response curve), so I cheated a little more and manually set it to 120Hz and here is the final result (the curve isn't as Flat as the 80Hz setting, but it is dang close):
And here is the Target screen for this graph:
Levels are +2 for FL, 0 for Center, +2 for FR, -1 for SR, -1 for SL, and -3 for Subwoofer
Using the new mic placement and changing the LPF LFE setting to 120Hz manually, my MLP (middle seat, front row) and secondary MLP (middle seat, back row) sounds better than it did with the Sub 25. Nothing is missing from my normal reference scenes, instead there is more detail in the mid-LFE range and the room is more pressurized in the ultrasonic range (sub-20Hz).
The other big plus is that while experimenting with Quick Measure I found that when the F25 is placed in the right front corner the major 60-70Hz null is mainly present on the two left side seats of the room, whereas when the sub is in the left front corner the null is mainly present on the two right side seats of the room. This makes me feel that getting a second F25 and placing it in the right front corner SHOULD knock out this major 60-70Hz null across all seats and voila! Time will tell obviously.
Edited by BigCoolJesus - 10/19/13 at 6:51pm