Pretty much what I thought, I d o hope to see more research into "alternative" design s tho. There is so much cool tech available a lot that was passed over.
I think this quote is why you are hung up on speaker designs.. The fact is, anything you can find on the internet has not been passed over.. or forgotten. The designs you've mentioned and others in books you'll find have been designed and tried but eventually failed usually due to one or more of the following.... COST, QUALITY, WEIGHT, SIZE.
The reason you see the current speaker designs out there is because that's what sells and gives the best sound per dB/dollar/size/weight.
You've purchased powered home stereo subs and mentioned stacking multiple together for more volume.... nobody does that because nobody wants to set up for a show, or even practice with 4 trips to the car just for your subs, and all the cables and plugs/power strip setup.. then you have your mids and highs handled some other way.. It might work but it's not practical for most people.
The contemporary speaker designs allow for loud low cabs without needing giant folded horns to increase sensitivity.. Flush front mounted speakers have sensitivity loss because of speaker/air impedance mismatch ( someone please correct me if I'm wrong on this ) but it's made up for by their improved power handling and especially massive power amps now available. Previously folded horn enclosures were required to get the most dB from every watt of power from lower powered amps and speakers that couldnt take 400-500 watts RMS each.
If you want to experiment with old designs and take advantage of their capabilities that sounds like a fun endeavor. I can only imagine the volume you'd get from a huge folded horn cab with the latest high power high Xmax drivers. Of course a single 15 cab will be larger than an Ampeg 810 but it would be cool to check out.
The current trend is high power in a lighter or smaller and lighter design.. or massive power in a standard size enclosuere ( Greenboy 151566 is a beast )
With the money it sounds like you've spent recently, it looks like you could have built a monster of a cab from current designs. If you go with older designs, you can have great sounding results, they will just be big and heavy... and that's why you don't tend to see those designs currently. The isobaric designs have some advantages and some disadvantages, but go against the trend of smaller/lighter/louder You could probably get the added low freq with a LF driver and mid speaker rather than the iso design.. And you're right back into Greenboy style designs.
...........whew... long post.
