If I could find a way to use these in my main system they would be used there. Unfortunately I am somewhat limited in the size of the speakers I can use so theses will just have to sit off to the side and get pulled out whenever I want to have a listen to them.
Any chance for a flat phase response on these went out the window when I decided to move the woofers back into the cabinet. Making that a low tuned (105hz) 4th order band pass does some nice things with filtering out harmonic distortion and reducing woofer excursion but it added a lot of delay. I believe there is >1080 degrees of phase shift in the design however it still sounds great to my ears. BTW if anyone is in the Chicagoland area and wants a demo give me a holler.
I am going to try making a DIY budget synergy V3. This one will use all off the shelf drivers while staying very affordable. It will be fairly compact as well, ~16-18" wide and high maybe 13-16" deep. Dual 8" woofers, two 4" mids, 1" CD. Should be capable of 120+ dB, f3 about 80hz, ~98-99dB @ 2.83v. I plan on making it similar to the one above with the 4th order band pass woofers. I need to build a simple horn and do some testing of the mids to figure out if they will cover the required pass band before I go further with it. If everything goes well I try and document the build so that others can replicate it, that is one of the reasons for choosing off the shelf drivers. If they turn out well I'll build three and use them for my LCR.