So, like you're original recommendation and then use the 24s for 30 and below? Pardon my ignorance, why would the horn and sealed integrate better than a ported NSW, like the "marty" or something like that? Just because it's tuned higher? I was thinking ported just for simplicity sake when building, but if the horn is that much better and can integrate with 2 or even 4 of the 24s I don't mind putting in the effort to build them. Any of those options is far less money that three of the 371's. Now, if the 371's offer above reference output to 35hz or so at my MLP, and integrate better and easier I'd not be opposed to spending on those either. My issue is I know just enough on my own to get myself into trouble and am still learning a great deal. I'd defer to the room designer as well, but the answer from them is "a full triad or procella, etc etc system with subs of their own brand". I would much rather sort the most capable system out on my own (with help from more educated folks like yourself and the others here, and then have the designer and calibrator work around that since the room is new construction and I don't have to make the compromises associated with a retro-fit.