Dirac uses "Curtains" to limit what it is allowed to control. I just drag the upper limit curtain left to 300Hz, and it won't touch any frequencies above that. So the stat panel gets nothing, and the woofers get corrected.I wonder if Dirac does a better job at limiting where it applies its corrections. I was using ARC with my Anthem AVM 60 and even if I lowered the max correction frequency, it still seemed to have an undesirable effect on overall dynamics. I would like to use ARC only on my surround channels, but there's no way to completely exclude the FL/FR channels, so there's always some amount of correction applied when ARC is engaged.
I first use ARC for the woofers prior to running Dirac. This has a much better result than either ARC or Dirac alone. There are some caveats however.
I drag the lower limit curtain all the way left to include all frequencies down to 0Hz. Then I add a Control Point as low as possible in Hz and drag it down as low as possible in Level. After that, I drag a Control Point, that Dirac already established at around 17Hz, up to about 18Hz. So the bottom most two Control Points are 18Hz and 0Hz with no other points between them. This creates an "out of bounds" area where all frequencies below 18Hz are squelched so my precious woofers in the Expressions are not bothered by frequencies lower than I want them to produce.
So, Dirac will calibrate from 18Hz up to 300Hz and not above, and will drop the level on any frequency below 18Hz down to zero dB so the woofers don't get bothered. Dirac is used for what it does very well, I don't hear anything odd, and the panels have all the life they can have without correction.
I learned about using the curtains in Dirac by following instruction by a fellow forum member on another forum. Thanks marcl !