For those of you familiar with bass box pro and/or winisd, help me out here.

The box is 2 cuft tuned to 30hz (12" rlp), 4" precision port

When I do this calculation (Lv=((8466.4*r^2)/(Vb*Fb^2))-(1.463*r) I get a number like 15.89". Winisd gives 16.28" with end correction being .614 (is that right for 2 flared ends?) And Bass box Pro gives a length of 17.35".

Which of these is correct? Or is there some other part if it I am missing? It seems as though they should all be the same length if my numbers are identical, but they obviously are not.

Also, a precision port ordered from PE is 17" in length with adding the flares and not cutting anything, correct?

Thanks

Both programs will be off a little or right on. Doing the hard math on paper will deliver the true results. I usually use BB as a means to get what I need as far as volume and and tuning is concerned and then double check and fine tune by hand. It's just simpler for me to use the program to get everything close first instead of just starting from scratch.

Either way, with the negligable difference in lenghts, tuning won't be altered much; tenths to hundredths, and your ear will never notice the difference.