my box design

[BMS]

http://tinypic.com/r/2djyr7q/9

link if the image doesn't appear.

Yeah i know the image is what it is so the triangles are my two woofers. 2 3500 watts rms each 12s pontiac grand am ct sounds 7k ect 3/4 inch birch. Now where should i add bracing the back is the longest piece that isn't braced but technically it is only a port wall so does it need it? the top and the bottom are obviously fine. the side walls are like half port or maybe only a small part will be like a few inches depends on how my dimensions end up and how much airspace i need because the rest of the port length will stick out of the box. the port is 8 inches wide but only 4 per side at the split to keep a total of 8 ( the numbers might change but the ratio will still be the same). it will be 60-80 inches long span the center of the car up to the head unit. I have been told something about ports being too long though. the goal is like 28 hz. let me know about bracing and the port thanks.

[Triticum Agricolam]

Anywhere you have an unbraced span of greater than 12" you might want to consider way to add bracing.

A 60-80" long port would definitely be cause for concern in my opinion. At that long you basically have a transmission line tuned to about 45-50 Hz. How that box will perform will be probably not what you want.

[BMS]

as in my upper range won't be good. to be honest i hate any bass above like 41 hz just don't care for it ill let the midbass handle those frequencies. i rally like from about 20-34hz I like lower too but it isn't really realistic to expect to be able to play 12 hz and 38 hz well.

[Triticum Agricolam]

The problem you are going to run into is since your ports are basically transmission lines tuned to the mid 40s you are going to get a big spike in output around those frequencies. Crossover frequencies aren't a brickwall that doesn't allow anything above them. They are a gradual tapering off. If you set your low pass filter on your amp to 40 Hz, for example, you will probably still get a lot of output up into the low 50 Hz range from your sub.

What subs are your running and what box specs are you shooting for?

[BMS]

Yeah i have 3 crossovers on it plan to really block off the top end what is wrong with a big output spike if it is tuned to 28 and i have a big output spike at 45 thats great spl and daily in one build. here are specs

specs are in series this is actually the first time ive seen them is just now i'm al little confused on the qts .5 is a lot higher than i expected

revc 2 ohms

fs 30hz

qts .5

qes .57

qms 5

vas .81 ft^3

spl 82.4 db 1w1m

xmax 25mm (ww-gap/2)

xmech 100mm

[BMS]

so based on the qts should it be actually be a sealed box i should put them in? don't get me wrong i like the idea if that is the case smaller size easier to build and better low reproduction in the really low end but based on how they look id never guess ill post pics.

[BMS]

http://tinypic.com/r/2l420o/9

http://tinypic.com/r/2lmx5qb/9

if those didn't work try this.

https://postimg.org/gallery/2t5pcfr66/

[Triticum Agricolam]

What box volume were you shooting for?

[BMS]

Well without a port i can hit probably 7 cubs total net of course i could put most of the port external. that is if i only want to use my trunk space

[BMS]

mY original plan was 2.25 cub per sub tuned to 28 hz 110 sq inch port area