My New C18 Focus Center Speaker!

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The "stand" I'm using is a petrified tree stump. On top is a IsoAcoustics Aperta 300 Center speaker isolation stand, which is perfect for the C18. The Aperta has tilt adjustment.

The dimensions from front wall to front edge of C18 is 32", and from floor to bottom of C18 is 23". These dimensions along with the MLP being 11' from the front wall is what eliminated a very wide 300-400Hz null from about 200Hz up to 600Hz.
I have the same problem [and actually had similar with my previous Motion 50XT, so it looks like some nasty cancellation from MLP and Stand]. My problem is that I can move only within approx. 20 cm forwards or backwards. I will experiment with adding some reflective surface on the floor. DRC helps,

Well, I have been tinkering with some things and a question came up in my mind.
Which speaker location ends up with a better correction?

In the case of the C18 I have had it on a stand with the front edge of the C18 being 32" from the front wall. This is where it measures better BEFORE Dirac corrects it. But, does this location provide Dirac with the "easiest" issues to correct? Apparently not.

I have never removed the wall mount for the C18 because it has been hidden behind the center speaker all the while. So I decided to hang the C18 on it and see what would happen.

Lo and behold it does indeed correct smoother! Who knew? Apparently, whatever is causing the cancellation between 300-700Hz, which is pretty deep when mounted on the wall uncorrected, and less deep on the stand, gives Dirac a bit more trouble when on the stand. So I've added one more item to the list of what to try when setting up a speaker, run Dirac for each possible location.

Frankly, I much prefer it on the wall, so it's a big win all around.
Well, after replacing a failed High Voltage Power Supply for the mid-range stat panel, I decided to take the opportunity of having the speaker on a nice work platform and remove the front grill to vacuum the stat panel. The speaker has been in use just over 1-1/2 years so there's got to be some dust in there, right?

While there is not much dust behind the grill, there is dust. So the area behind the grill is not immune from collecting airborne particles. So I wiped down the solid surfaces, carefully, and then vacuumed the panel. But do I reinstall the grill, or leave the panel and woofers exposed? hmmmm . . .

The bottom panel of the speaker has a bunch of screws that attach it to the speaker cabinet and also captures the grill into a slot. It's not difficult to remove, but it's not something I'd advise against doing multiple times a year. So I think I'll leave it removed for now and find out how things go.

So I'm sitting here wondering if there are other considerations besides occasional cleaning? The grill is perforated to allow the sound to come through, but does it "hinder" the sound? or does it "aid" the sound by diffusing the audio waves and making them less directional? Does it matter at all?

I, don't, know.
Sounds better with it off for me. Did the same on my Focus and now my illusion. I'd take it off my 15A panel if I could....(kidding)