need some help, building a box for two dc LL 4 15,s . I'm ready to install the ports but not sure how long to cut them. I'm using four four inch psp aero ports(only using flare on port exit)subs will be seeing 1000 watts RMS each my box volume after bracing is 7.49 cubes . the psp port calc is giving me 13.68 for a straight length and 14.68 for the flare length not sure which to use wanting tunning to be 33 Hz this will be a daily , not really going for straight spl but want good lows. could some one take a look at this and give me a push in the right direction thanks in advance.

I would recommend using flares for both inside and outside.

i bought the precision port kits with every intention of using both flared ends but i have been running into problems all the way. i didn't have as much room width wise as i thought i did and i am about two inch's shy hight wise so i can't port the rear deck like i originally was going to. so what i did was tubbed in my spare tire well and built my box on top of the tub.

i still don't have enough room width wise to put the ports on the face of the speaker box so I'm firing them up through the tub. the problem there is i only have eight inch's from the bottom of the tub to the top of the tub floor so i think using the flares on the inside may cause port noise being that it's such a confined space. i thought about scraping the flare ports all together an using a slot port or vent type port but i personally have never built one and not sure of the length or width that i would need to achieve the 33 hertz I'm looking for.

Ive asked for help on this forum and others but seems like no body cares to lend a hand , I'll get it all worked out eventually.

Dimensions of your box?

Ill help you out

What type of vehicle do you have?

Give us time were all here to help.

my car is a 2005 Hyundai sonata,the box itself is 16.5 h x37 w x 18 d. but the interior floor of the box is open and sits on top of my spare tire well . my tub holds 20 gallons of water which i used a conversion chart to figure out gives me 2.67 cubic feet of air . i have 37 inch's wide on the tub but because of the curves it kind of takes away from the inside width so what i end up with is about 33 inch's wide to work with that's not a problem.where it's getting tricky is i only have 8 inch's of depth inside the tub and I'm using four inch aero ports , i had to get some PVC ninety's to bend them out but they are resting rite on the tub floor so thats not leaving much room from the floor to port opening also still not sure about the length on the port .

Im a little confused

Have any pictures so i can see exactly what your talking about?

no i don't have a camera but basically what Ive done in short is tubbed in my spare tire well and built a box to sit behind my back seat firing into the trunk on the inside of the box the bottom opens up into the tub to give me my added air space . since i couldn't fit all four aero ports on the face of the box with the subs i figured i would fire them up through the floor in front of them twords the trunk lid. I'm open for suggestions if you have an idea that you think would work better like i said earlier I'm willing to scrap the aero ports and work with a slot/vent hell at this point i would even try a different box.