Open Baffle Opinions - I Won't go back to Boxed Speakers Evr Again (maybe....)

My very last DIY effort after doing the DIY Speaker thing (for myself only) for 35 years (only 5 pairs built in that time). These are my best effort WRT to sound quality. Bass down to 30Hz, sweet treble and midrange to die for.

All Parts Express Drivers. GRS Planar, GRS 12" (Qts = 1.27) Woofers, and Dynavox 5 1/4" midrange/midbass Drivers. All in $600. Still some tweaking to to on the Cabinet and the Crossovers. A simple 1st Order 16uF Sonicraft Capacitor on the Tweeter and a 2nd Order Bandpass on the 3 Dynavox Drivers. The H-Frame Woofers section is powered by an ICE Power Class D (1000W@4 Ω). Two for stereo of course. MiniDSP dialed in for a 250Hz Linkwitz-Riley 4th Order LPF, the Bandpass is 250Hz - 2500Hz, and the Magnetic Planar BG knockoff by GRS takes over at 2500Hz. No L-Pads anywhere !

My question is what is the Phantom Center like ? Mine is not as focused as I’d like it to be. But my God, the soundstage, imaging, front to back depth is amazing. Clarity like I’ve never heard before form a Box Speaker and the Bass is like I’ve never experienced. No Box Boom. 40Hz all Day and I can hit 30 Hz with very little attenuation

@quadprod :

You make some excellent suggestions regarding using active X-overs and Finite Impulse Response Filtet also can more precisely help with some of my issues.

But as I’ve stated earlier, I don’t want to feed the Analog output of DAC into another DAC (of sorts).

Fixing my room problems for me is the key to getting that damn center image sorted out.

I’m almost there. Built a 2’x4’ Skyline Diffuser for the back wall behind the sofa and an building two smaller 2’x2’ Skyline Diffusers for behind the Speakers (preferred WAF) or on my 1st reflection points where I have absorbers currently.
Try active crossovers and amping. Try it, don't speculate it in an online forum where 90% of the input will be from individuals that don't have any firsthand experience.

agreed, and I do have experience with this. Pure Music and Pure Vinyl are  excellent options. Built in crossovers 2-3, or 4 way with adjustable amplitudes and delays for time alignment. They also accept AU plugins so you can EQ, I used Fab Filter and  recommend it but there are many others. Next you need a Pro Audio interface to get the active outputs. Again, many excellent options at various price points. Lynx, Antelope, RME, and others. I triamped my system with great results. The interface is your DAC which is what the pro's use to mix the music you listen too. Many excellent choices at a fraction of what you pay for overpriced "audiophile" DACs. 
To expand a little on Ralph and bdp's comments, many years ago Bell Labs research found that a delay of at least 10 ms between direct and and reflected sound increased clarity and definition.  Any time less that that leads to smearing of information.  So it is important for any dipole distance from the front wall.

As mentioned, sound waves travel at something very close to 1' per ms. So 5' minimum distance out from the front wall is recommended.  When that distance is not possible then diffusion panels should be utilized.

This applies to all speaker designs for sidewall distance.  The distance from front baffle board to the first reflection point on each sidewall should be 10' greater than the distance from drivers to the listener's ears. 
I agree with the OP. Once you’ve experienced OB’s you’ll never listen to a box again. Fact is, my first set of speakers were boxes but featured a Heil AMT. I enjoyed them immensely. Since 1980 I’ve owned electrostatics. In 2010 I discovered OB’s made by an audiophile whose main gig was producing 30’ boardroom desks here in Seattle. The man had serious woodworking skills, and his OB’s were sensational. He began building speakers which had a following. He built the Hawthorne Rainiers which featured a huge Heil version in their center. For woods he’d use Sapale or the finest Birch you’ve ever seen. I owned two different pair over the years which featured 15” woofers. It’s the finest natural sounding bass I’ve ever heard. Yes, once OB, never back. Fact is, there’s a ton of OB options nowadays.
@coltrane1 That's so cool. My woodworking chops ain't the greatest but all my DIY Speakers have always had a DIY look and feel to them. Not by choice. I am not a Carpenter (but I wish). Here the rear wall Diffuser just completed and hung today. Two more smaller one's are going up this week either at the 1st reflection points or behind the Speakers on the front wall. 

Phantom Center is much improved but add smaller diffusers should tighten the Phantom Center. Or that's the hope anyway.