pnutz37

I also recommend pulling the TS parameters of the sub. This will get you a more accurate graph on frequency response etc. I have a Fi Neo 4.11 18" and the parameters are way off.....

I agree something isn't addiing up. I'm surprised that your impedance rise goes up to 4 ohms or so on a 1 ohm load. I was running 6k rms (rated power not AMM-1) at 2 ohm load and at or close to tuning frequency was at 5.2 ohms (6k rms amp rating down to 2,800 watts on the subs with the AMM-1). In my testing of a few systems that I've set up for myself and a couple that I've helped tune I've never had impedance rise go that high (except maybe at some lower volumes and higher frequencies). One thing you could check out is the settings on your amp (if if you're running it through a DSP). I was also running a taramps smart 3 and even with some minor adjustments to the low pass filter etc it made a big difference on low end performance, rms output and db's.

@1point21gigawattsLots of wildfires where I’m at. 253 active ones.

That port is way too small. You should be looking at between 12-16 sq in of port are per cubic foot of box volume. I'm at 24.5 sq inch of port area for my 2 8's and it's just a tad too small. I am assuming you entered in the size of the port you wanted to build because that website and calculator allow you to enter the values. It's not telling you the size. It "blindly" gives you the length based on the parameters you tell it. Another thing that I'm assuming you didnt allow for is deducting the port area and length (so again cubic ft) from the box volume. Your port volume is quite small so it probably didn't make much of a difference. I'm sure there are a few other guys that could weigh in on this (I'd consider myself a noob for box design and building but I think most of what I have said is true)