Though they looked okay, both needed to be reconed. The cost of the recone at Orange County Speaker was less than half that for new drivers, so I figured I made out pretty well. These are fairly high end bass drivers, which gave me the warm fuzzies.
So, with a pair of fresh drivers, I set about designing and building a matched pair of bass cabs.
The plot is actually pretty typical for a 12" driver in a 2 cuft cab. The low frequency tail-off looks a whole lot bigger than it is, as I don't really have to EQ for it. The cab is tuned to 53Hz. Any higher and I'd have lost too much bottom end; any lower and it looked as though it might have gotten a bit farty.
What you see below is a design very loosely based on Epifani UL112 cabs. Height and width are the same as the UL112s, but they're an inch deeper. The extra inch in depth gave me a little additional volume that I could soak into bracing. Good bracing is important in a bass cabs, but even more so here because of the 12mm (about 1/2") walls. I don't have an UL112 to take apart, so could only speculate on what goes on inside with bracing and porting. In the end, I did my own bracing and porting and it all works very well.
The cab carcasses are built using 12mm Baltic Birch plywood with all dado & rabbet construction. Drivers are mounted with 10/32 machine screws. There are brass inserts for the woofer and T-nuts for the tweeter.
Interior corners are gusseted with poplar triangle strip. Extensive bracing is with nominal 4/4 poplar.
All loaded up for a quick test. There was actually a test cab previously built using cheap plywood to test basic functionality. The tweeter is an Eminence ADP80 being fed through a one-way crossover at 1500Hz. The 3" ports will be glued in place with epoxy.
All finished, wired, and fiberfilled. Acoustic damping material is 1" fiberfill purchased at Jo-Ann Fabrics. Paint is Duratex. Handles are spring loaded and mounted at the balance points using 10/32 machine screws. The round objects on the baffle are rubber feet that are used as standoffs for the grill. They're attached with a couple of nails driven through the rubber. Machine screws will extend through them into T-nuts to hold the grill in place.
Grill is aluminum perf sheet hand sanded with 400 grit paper and mounted with stainless steel machine screws through the standoffs.
Finished weight is 37.5 pounds each and the sound is phenomenal. Each cab cab handle 350 watts continuous (equates to RMS), 700 watts peak. Lots of thunder here.
Ken...
