Hi,
I need a little help figuring out how to make a midbass (50-300 hz or so) midbass/bass horn for my newest line array project

I was going to use 8 10" midbasses in just a normal line... but I believe better results (and cheaper) can be had with a bass horn...

I would like to try a 2 15" or 2 12" (preferably the former) per tower midbass horn... I'm unsure about the length and the area "inceasing rate" of a horn like this

I would like it to look like this diagram... but I'm unsure if this would work...

two major questions... will this setup be louder than 8 10's ported??

and is seperating these two horns and having one side perfectly horizontal, will it work like I drew?