Finally I'm moving up from a pair of dual opposed 18" subwoofers (Dayton RSS460HO-4) to dual opposed 21" subwoofers! I'm still keeping the 18s in the system, of course! I've been eyeing these drivers ever since
had built his. When I ordered mine I specified to have them made just like Luke's!
So thank you Luke for the inspiration and for answering my questions as well. ( It's also thanks to him I've acquired a pair of Othorns, so he must be good influence, right? )
The subwoofers were ordered roughly three weeks ago now, which I got a nice black Friday deal on, which really helped push me to go for it, and they'll arrive here by freight tomorrow.
The Cabinets will be 23" W x 24" H x 43" L, out of baltic birch. Doubled up on the baffles so they are 1.5" thick. Otherwise the rest of the thickness will be 3/4". I've calculated that 11.198 FT³ in internal volume before inner bracing and driver displacement. Then 10.5042 FT³ after bracing and drivers are installed.
Each cabinet's width is at the maximum allowable size that I can fit due to how my Othorns and current dual opposed cabinets are taking up so much space, which I probably could have went a little higher on the height, but I didn't want to bring the 1099s up any higher than they already are. Depth was also a limiting factor, since 43" L is already pushing it. Otherwise I would have simply bought Luke's old cabinets and called it a day but those would definitely stick out way too far!
Currently the plan is to have three inner bracing, but I do have enough material to make it four if needed or if I felt the need to.
Yesterday I spent all day getting the material cut and ready for the next steps.
I ended up having a little helper here.
Then all the material waiting further work.
Tonight I plan to get started on routing the baffles and bracing, and hopefully get started on assembly tonight or tomorrow.
Also once I get everything going I'll probably have to steal my Peavey IPR2 5000 away from the Daytons to power the 21s, until I can get a SpeakerPower SP-12000 amp.