Here is a 4th order bandpass for a 12" RE XXX. To cope with the considerable weight of the sub the entire box was designed with 2 layars of 3/4" MDF. There is a rear access panel as well as a mount for the motor of the sub. This will decrease the amount of torque on the screws the sub are mounted with. The port was rounded over to ensure there was as little chuffing as possible, even at high output levels. The customer wanted to have a lexan window in his box, and it was taken into account with this design.

This is vented box for 6 Incriminator Audio 187 15s. The extensive bracing in necessary to prevent the panels from flexing. When the baffle which the subs are mounted to begins to look like swiss cheese, as in this case, it is always recommended to use a double baffle. This is to ensure that the baffle can support the weight of the subs. It also increases the stiffness of the panel dramatically, and thus helps to reduce flexing. A square port was used instead of a slot port to avoid issues with the placement of the subs.