Need help with Aero or slot port design (Going for more bandwidth than SPL)

[FishinForBassBumpinDaBass]

Hello everyone. I'm a very very long time lurker and never had the need to make an account until now. Just glad I got to have a sick username lol. Basically I'm going to get someone to build a box for me for my new build (hopefully the last for a while) which consists of 2 sundown U 12's v1 d2s on a jp33 at .5. It will all be powered by a 280 singer and 48ah of glowe voltage LifPo4 cells (the new series 2). I've been buying the stuff for the build piece by piece when I can find a good deal and the only things I have left to get is the 2/0 welding cable and the Box. The build will be going into my daily which is a 2015 Honda accord sport so space is a challenge I have been facing since I need to be able to fold my back seat back up when I'm not bumping when people need to ride with me or I'm driving my son somewhere. Before anyone say anything about me building the box myself it would be out of the question. Trying to balance college, work, and family hasn't left me with much time to do much of anything and its going to be a struggle to find to time to get everything installed before the summer is over since I am taking summer classes. I'm particular about my sound so I want to make the guy a rough design or at least tell him what my goal is and how I want to position my box. My three options would be 8-inch aero subs forward port side facing drivers side, Slot with subs forward port foward on drivers side, or subs foward with port side facing drivers side. Take into consideration that my box will be scooted at the back of the trunk since I will be putting my amp and fans at the first part of the trunk. I have no idea which of the three would be the best for overall sound quality, bandwidth, Spl, etc. I would like to have some wind if possible, but that would be something in the back of my mind. When considering the best design, note that I would gladly sacrifice 2-3 db for a wide bandwidth and if similar results can be achieved with a slot I would rather not spend $100+ on a vera tune port. I mainly listen to rap, but when I play classic rock and sq songs, It would be nice for them to sound decent. Sorry about the long ass write up I just want to do it right the first time. Thank you in advance to whoever repsonds. 

[Joe X]

The sundown U12s play rather peaky, you can either build a box with a net volume lower than recommended or use damping material inside the box like polyfill or dacron, sometimes an inefficient port can help with a peaky output (long port or lower port area) but if you didn't like the results the box is already made. the most effective solution is build a large sealed box, secondly use proper subs, or the methods mentioned above.

[FishinForBassBumpinDaBass]

@Joe X Thank you! I think I might try tuning lower (29-31ish) and go with something like 11 Square inches of port area per cube to help with that a bit. The box I have now is kind of a one note wonder at 38-42hz and rolls off very quickly. As long as I could get a bit less rolloff I would be happy with it. I think doubling the cone area and power that I have now will help alot where the single lacks and I wont worry to much about it playing flat. It seems like I picked a bad driver for a semi flat responce but it does seem to be pretty musical for a spl driver. I was thinking before to do maybe 4.5 ish cubes net but now I think I might knock it down to 4.15 net. would 2 4 inch aeros be better than a single 8 in terms of helping kill that peakyness.

[Joe X]

Really controlling port area is not necessarily the preferred method to reduce a peaky response, reason being at high volume you may get port noise and at lower volume does nothing to help the peaky response, 

 

Here is the U12 v1 in orange without damping and in yellow with heavy damping:

 

Box is 2 cubic feet net per driver @ 35Hz.

 

 

As you can see you get a sharp drop in the peak and a somewhat softer rolloff, additionally it doesn't change (up) your tuning as cutting volume would do.

 

If you are not listening to lower frequencies enough then just tune lower as needed..