New Cabinet for Zaph's SR71

[npapp]

Hello,
I am currently in the planning stages of building John Zaph's SR71 project from Madisound. I am building my own cabinets and plan to a beef up the overall structure of the box, based on cabinet plans I used from some North Creek music speakers i have built in the past.

I am not changing the baffle width, but I would like to move from the rear mounted port to a front firing rectangular port. How do I calculate the new port dimensions? I am maintaining the 14L volume of the cabinet and I want to tune to 44hz as per John's recommendation.

I am searching but not finding a good calculators. Please help.

I have included some initial modeling of the cabinets. The port in the picture is where i plan on placing it but it is not at any specific length.

Thanks, Nick

[Salas]

Its easy to convert. You need the rectangular port's mouth surface to equal the original tube's round mouth surface, and the length remains the same. Pi * r SQ must be converted to hXw.

[npapp]

Here is a photo of the inside. You can see the port placement I am considering.

[npapp]

Thanks so much...sorry about the novice question. Any audible down side to the square port?
N

[Salas]

Not really, sturdier actually bcs it is normally made of wood panels. Just round its lips.