port size/ length, input and help needed

[southernboom88 10+ year member]

Just wanting to double check my numbers. Just build a box for 2 sa12's, 4.11CuF after displacement, will be seeing about 1800 watts rms. this will be a daily system that i may enter in some comps. thinking tune to 33hz via aero port. I'm thinking a 6" flared port, precision port calc says it should be 13.6". does that sound right? Any input on a diff tuning or route is welcome. Thanks in advanced.

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[bbeljefe]

If you've already built the box and plan to put a vent inside it, you will change the internal volume of the box and thus, not get the tuning you desire... unless you do a lot of vent displacement calculations in order to find your tuning.

It's a good idea to calculate tuning, vent, sub & bracing displacement before you build the box.

But yes, that length sounds right for 33Hz if the vent doesn't change the internal volume of the box.

 

[southernboom88 10+ year member]

thanks, I did account for the displacement of the port itself. I believe the calculator i used accounts for this as well.