orion old school 15d hcca box redesign thoughts

[88pro2]

I just finished my custom box to fit this in my 2000 f350 std cab.

It comes in right at 4cu ft as they recommend.

It has 2 4x14 ports, they each exit right next to a door close to the floor behind the seat.

The sub is facing forward at the front of the seat edge where console used to be.

I replaced center console seat with this box and it tee's off behind each seat to get the desired cu volume.

Testing has sounded good, but I noticed a few things.

With volume holding steady, if I open the windows about 3 inches the subs volume seams to jump.

Tonal wise it sounds pretty good.

Is the cab to small for the 15 to produce proper waves?

Are the ports getting loaded into the corners and in effective until windows open?

I could redo with ports facing up dead center at back below rear sliding window.

What about a slot port right below the window.

What size to replace 2 4x14 round ports?

Is the sub loading into dash and needs windows open to raise the music air mass??

has about 12 inches to lower dash stuff in front of woofer.

Should I face sub up or down and port forward or up?

Very limited on options with space confinement.

Do I get a 15 for a smaller cu ft box?

My original 2x12 Image Dynamics sounded fine behind the seats in 2ft sealed, but I want more.

Blow through is not an option.

Any thoughts or suggestions?

[88pro2]

Did some research and found an article talking about these(12" though), sounded like the person possibly worked for Orion by the way he wrote the article.

One conclussion I can come up with, is my ports may be to far from the woofer face.

The article said to put the ports on the same side as the woofer.

Maybe I just have the ports to close to the corners of the door and back wall to get air in properly.

I found that at even very low volume there still is a noticeable increase in output by opening the windows.

There is hardly any air moving through ports at such a low volume that alone might eliminate the distance issue or placement.

Maybe his idea was so the port tone blends with the speaker output better.

I do have the back cab blow holes covered by the box, I guess making this an air tight cab, possibly acting like a dual chamber box(bandbass?)?

By opening the windows I eliminate the front sealed area, thus finally making it work properly?

These speakers are supposed to work best in a ported box, altough he states they can be used other ways but won't optimize the speakers design.

They do sound pretty accurate and hit harder than anything I've had before, I just can't figure out the volume boosting issue with the windows open.

Any thoughts????