29w x 14h x 14d make my 2.48 cuft box taking out the .16cuft so that makes it 2.32 cuft well i want to tune the Fi Q to 32hz and here is what the port calculator tolds me that: at 4" diameter it would have to be 11.33in long is that correct? BTW i used the the12volt.com calc. thanks
Using those as outside diameters with 3/4" mdf gives you a gross internal volume of 2.49 ft^3. Subtracting port and driver diplacement gives you a net internal volume of 2.24 ft^3.
A 11.33" long 4" i.d. port will get you a tuning frequency of 32.86 Hz. If you want a tuning frequency closer to 32 Hz use a 12" port(12.17" to be exact).
If you decide to go with these numbers tell me and I'll double check things for you. I think you might want to go with a larger or flared port though. According to WinISD you may get some chuffing with more than 300 watts otherwise.
This also assumes you're going to be using a subsonic filter. If not things could be worse.
Remember this is computer modeled and might not apply to the real world all that well. Might want to check around and see if anyone here has built a ported enclosure for a Q12 and find out what size(diameter) port they used, and whether they experienced any port whistle.