I'm about to build a ported box for my Dayton ho10d4 and I'm getting some strange vent mach results with winisd. Box will be 1.2 tuned to 29hz with sub firing into the seat of my single cab truck and port(s) out the side. I'm going to use an aeroport over a plain slot. What I'm second guessing is how the vent mach is way lower with a pair of 2" ports vs a single 3" port. The single 3" port is just shy of being in the red for vent mach. Am I missing something here or is winisd just plain wrong on this one? Common sense says the pair of 2" ports should have a slightly higher vent mach since the pair has slightly less area than a single 3" port. I'll have 600rms available for the sub but it will never see anywhere close to that for daily listening. Been wanting to try this sub ported for a while and it's an itch that needs to be scratched.