It doesn’t matter I was just curious. Ports too small I personally wouldn’t attempt it. I would be worried about chuffing and poor output. I’ve built a couple of boxes with the port on the small side but they were built for sq not output. Even those had more port area.
I’d go sealed if you’re not willing to sacrifice space. Really though if I had it I’d probably use that in the garage and put a modern 12 in a ported enclosure if wanting to get good output in a trunk build.
By 25in2, do you mean a 5"x5" square? A 4" round port has an area of 12.56", If anything I would make the slot port 12.56" x 1". That would give me the same area as the 4" round port. Then of course I would make it 7.75" long.Usually something that calls for a single 4" aero will need 25in2
We are all noobs. I just recently learned that audio engineers disagree as to speaker efficiency proportional to voice coil size. Anyways, what I have read (many moons ago, so no source) is that ports are holes designed to control the airflow that a cone moves, therefore controlling that cone resulting in a resonant frequency. The same theory is used in passive radiators, a weight is used on the radiators to control the movement of the speaker, also resulting in a resonant frequency(tune). Now this is something I read so I claim no knowledge of the dynamics of these studies. What I did deduce all by myself (pops collar) is that port surface area x length is what matters and not shape. I may be wrong from here till kingdom come, but twice it has worked for me. On a pair of old 15" Punch and a 12" Elemental Designs eD12a (I love this sub).Ima noob too... I'd love your input on this as well.