Long story but these cabs originally housed a Altec 15" woofer and 811 horns. After a "bit" of modification, they now have a 3 cu-ft sub enclosure for the 2226's and are tuned to 38. The rear porting was not the plan originally, but came about because of lack of room to allow for it on the front. I guess you would have to view the interior framing to see what I'm getting at. They are about 5 cu-ft internal volume overall. The pics of the crossovers I built for them were taken prior to final changes.