The horn itself doesn't go below 150Hz, even in a corner. If not in a corner, it won't go below 250Hz. Really, as it is intended for vocal range, that's fine. I wouldn't do the vented-rear chamber with a Delta 10 or JBL 2012, and would use them with a sealed back for their intended use as a midrange horn. But the Alpha 10 is a pretty good little midwoofer, and it delivers deep bass. It occured to me that it might be suitable for something like a mini-VOTT.

So the eight π is really an unintended exploration of the retro Altec style cabinets with short front midhorns and bass-reflex bass. It's cool looking, and should work well as at its price point, being somewhere around the cost of the higher priced Thermionics. In kit form, maybe even cheaper.