So we had a customer talk about getting some bass on his bike and I had a solution in mind. I took a set of True Kustom "Heavyweights" BIG saddlebags and built cabinets on the inside that are ported outside the saddlebag. The only way to get good sound out of subs in bags. The ports are seven inches long and shoot out the bottom. Being we make a ton of fiberglass stuff this wasnt to hard to do. The hardest part was calculating the cabinet volume inside the bag and all its complex shapes. 1/4 cubic foot for a JL Audio 6" subwoofer, these little guys are nasty. We built templates for plates first then made the flat shapes out of fiberglass and glassed them into the bag. The port calculation was the next trick to figure out. Once I had the math done we built a long rectangle port and fit inside the speaker cabinet pointed down to the outside of the bag. A couple guide holes from the inside and we cut the hole in the bottom of the bag.