I've see a 1987 drawing by Paolo Viappiani, a tiny driver scoop with one fold more, just a duct but I wanted to remodel it for a 12". and Here's
[attachment=0:1yyfxzeh]<!-- ia0 -->2fold12.png<!-- ia0 -->[/attachment:1yyfxzeh]
external dimension is 37.6*94*70. I wanted to make 12" scoop to drop closer to 40hz (emi can't) I know for it's dimension it's pontless, you can use a bigger driver with a classic scoop layout, and the same driver work good in some tapped horn but......I don't care smiley2
I make stupid errore as usual, the width is 48.6 like the eminence 12", so the sim are correct but not the drawing now is correct
some mod to make it works with more "muscular driver". Reduced throat to 2,7 cm and a proper expansion in the first horn part.
[attachment=3:2j2hrslf]<!-- ia3 -->2fold12b.png<!-- ia3 -->[/attachment:2j2hrslf]
[attachment=1:2j2hrslf]<!-- ia1 -->viappb1218sound12lw1400.jpg<!-- ia1 -->[/attachment:2j2hrslf]
[attachment=0:2j2hrslf]<!-- ia0 -->viappb1218sound12nw530.jpg<!-- ia0 -->[/attachment:2j2hrslf]
and courtesy of Bee, last but not least, b&c 12ndl76
[attachment=2:2j2hrslf]<!-- ia2 -->viappb12b&c12ndl76.jpg<!-- ia2 -->[/attachment:2j2hrslf]
By the way I'm not really sure that a tight throat like this can have a good sound.
P.s. in the first version can work 18sound 12mb700 and some faital pro like 12fh500, pretty bored to sim other drivers