Yes, the move from BLH to front-loaded is a large move but besides everything it is a very drastic way to review HOW the channels are positioned relative to each other and relative to the room. With front-loading the subject of phasing become critical. With BLH the phasing is so fucked up that there is no real needs to think about it as you are in absolute mess. It is like a symphonic orchestra with musicians sit all over the concert hall, 100s feet from each other and in random locations – there is no such a thing in this condition as to “play together”. If you however, arrange the musicians in proper section and position section in proper location then the subject of “timing” or the subject “when to start playing” because important.
It looks like you did not figure out how to use the posting interface as your text is corrupted (I might fix it) and your images did not go through. It is hard to recognize what you are trying to do without the pictures. Anyhow, a few comments regarding to what you have exposed.
Your LF section, the Tuba by Bill Fitzmaurice. I do not know what it is. I hate Bill Fitzmaurice and consider him being an idiot and I truly do not pay attention to any brain defecation that come under him. So, I can’t not judge or care what Tuba. The O-Audio 300 BASH amp that you use to drive your LF section is a controversial subject but there is a lot more to it then juts the amp.
The John Inlow’s paper horn are great. I do not use them and from the purist position I do not endorse them but I do admit that the paper mache horn that John Inlow advocate is wonderful idea. I have a few friends who built the paper horn years back and I very much like the concept. The key in it is to find some kind of prime according to which the mass and the resonance of the horn would be somehow “talk” with the horn rate and the driver’s primary resonance. If to tune it in the way how musical instruments are being tuned then it is possible to built an ultra-light, self-damping horn where the lightness of the horn will not be negative factor, or to be even a positive factor. I do not see anybody talk or look into it and the folks who experiment with paper horns feel that they make “poor man horns” but I do feel that with proper level of seriousness the direction is very perspective.
The Stereolabs 250Hz horn and Selenium D405 drivers. Am I cringing? Why shall I? I never had that Selenium 405 driver and do not know anything about it, so I have no reasons to like or do not like it. The same goes to the Selenium D220TI - I never seen it.
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche