Cubo 15

Something like this:

Hi everybody,
I had a question regarding Cubo 15.
I need to build subs for a theater play. I want them to have the lowest frequency possible, mostly to play things like effects.
I have a lot of Eminence Beta 15A, and was wondering if I could try to build Cubo 15 with them. 
For me it would be the regular design with magnet visible ?
Would you have other ideas for a project like this ? (THAM 15 ?)
Thanks a lot !

Any advice ?

> simulate it as a rear loaded horn (or TH)

Tapped Horn by all means. The Cubo bins are tapped horns within the guidelines that are used to classify within HR, and you'll get by far the best results using the TH mode.

(my previous reply seems to have been disappearedied)

TLDR: The Eminence Beta 15A is a midbass woofer, not a subbass woofer. It's unsuitable for the Cubo, the THAM or any horn enclosures. Aim for a bandpass(-vented) enclosure, or ideally, sell them and buy something suitable for the purpose; even in the best case scenario, the Beta 15A will not provide what you seem to desire, no matter what you end up with as for vented enclosure either. It's just too weak, sluggish, and won't work in a horn by any reasonable metric. 

Thanks for the developed answer ! I will try to find another speakers to build this cube 15