I have looked at all speaker design repositories that I could find. The two older existing FLH I have are not that powerful by todays standards, about 137db for the pair, but it would be nice to couple them with two more FLH ontop and the HessBH is same face geometry. The kick will be a c-2d 18", right now like HessBh is the most modern design no compromise solution. Punishers have aged out, except maybe with the horn expansion flares? Still don't like the response, I am doing c-2d kick, maybe better off going with paraflex, bandpass, or even reflex and ditching the FLH coupling idea? The efficiency of paraflex would definitely be nice on limited voltage.

 I guess reflex would still be in phase if I corrected them. TH wouldn't work and I'm not a fan currently. Paraflex I would have to ditch the FLH entirely likely. And that might be the best approach on limited electrical. Other plans 18sound, lavoce, etc FLH don't dip low enough. More like 50hz horns and definitely not 30. I could have a try at oversizing one of these but for my first CNC i'd like pre-existing plans or editing existing plans like with https://freeloudspeakerplan.rf.gd/ shout out

Anyway, is there anything "better" than the HessBH? 

OK I've heard from different people who stood in front of side by stacks of hessbh and the og SBH that hessbh WAY better and there's no reason to be doing SBH's anymore, and its not just a simplification. I'm honestly not even sure what you are basing that on, have you heard them in person? Sounds like operator error. 

I listen to a lot of dub, dubstep, trap, wave, 30hz experimental bass, So 45 hz low corner even with the extension flares with the Punishers just isn't going to do it for me. In any case, the more I hear about paraflex the more I think it's just hype, sorry para lads out there. So the SAPfx118 I wouldn't need kicks.. but am I going to have enough sub 40 info. I am back to thinking about scoops, since I'm building 4, like oversized fanes or polars, but then I'd have to do kicks. Then again I would need kicks with the hessbh too. Anyway sorry if you heard 'em and didn't like. I'm pretty much fully back to the drawing board, the one tbw100 in a reflex in my room is already super duper, I'm content to just running senarios/sims for now. Every other report on the hessbh has been "its the new best FLH" 

I am considering if my dream of FLH is worth the extra wood and inability to transport without a trailer. Will be a while until I can afford the ply, have a lot to consider before then, like why am I doing this if one 18" reflex is already more than enough for my room 

The tbx is definitely xmax limited in the hessbh. That could be your friends issue, since the moment they are pushed barely over xmax it will just say "no thank you".  I have mixed 18" subs rn, 2tbw 1tbx, 1 prv (b&c clone) but in the future hopefully all tbw and move the tbx to 18" kicks. Got all open box building it totally myself without a crew so financially its taken a while and not close to being finished. I may build some reflex that can be used with all driver types, no need for kicks, or just one kick, and a lot less plywood. If they aren't being played outside that much this might be better fidelity approach. Thanks for sharing your experience. 

ah yea I found these just of the simple folds if that's what you mean, would take a bit of work. I really like the design though