Well I built a box from some slightly modified* premade plans a while back (unmodified) ImageShack® - Online Photo and Video Hosting which was working just fine and dandy for my hifonic brutus 12s running at 600rms, but one faithful day I was finishing helping a friend test if his amp worked and re-hooking up my amp when tragedy struck: a thin strand of wire from the positive was shorting on the case. Fried the amp and I was heart broken, lost without my subwoofers. Well as fate would have it I came into some money and grabbed an audiopipe 1800w amp and had the system back up and running. Well this was an increase in power the hifonics couldnt take and the one literally ripped itself in half http://i.imgur.com/quqOd.jpg and the other popped its coil. So I was browsing the classifieds here and came across a good deal on some new okur 12in k9 D4s and grabbed em and shoved them into the box. A few months later I had soul survivor going and was feeling a "thud thud thud" other than the bass, so I look back (this is in a wagon) to see this 100+lb box jumping 1-2in in the air. Well the subs are downfiring, I extended the walls of the design to clear having the woofers on the underside and the plate they are attached to ended up shearing 6-7 screws on the long side that attaches to the back wall so it was flexing enough to launch the box upwards. Found each sub had 4 sheared screws as well.
So here I am, I need to rebuild this setup and Im thinking this design is too generic for what I need. My issue is despite being good with figuring out the construction, running wires, hooking **** up, I am terrible at box design. I want to build this around the specs of the k9s to really make them sing. If I remember the width and depth of the first pic in the orig design I posted are the max I can go, but I can go taller to some extent. I plan on building this to handle more power than I could throw at it without rattling apart. Double layers of 3/4in mdf for almost everything, found some awesome T nuts to bolt the subs into place.
Right now it only needs to hold up to the "1800w" the audio pipe is throwing but soon when I get the IA20.1 im sitting on repaired itll need to handle an actual 1800-2kw.
So basically what Im asking is can someone help me with a good design for these woofers that is going to be strong as well. Im willing to pay for the blueprints.
**** almost forgot the list
1990 volvo 740 wagon
35-36in wide, 20-21in deep, 17-22 tall.
2x DB Drive Okur 12in K9D4
I play plenty of rap/dubstep/etc so looking for deep hard hitting bass so spl is the goal
Looking to tune near 38hz but only because thats what the manual for the woofers is saying.
*Modified plans: Dont have an image but all I did was turn the subs from the side with the port to being on the underside if the port is facing you and is on the left. I then extended the back left and right walls down about 2-3 in to clear the subs being on the underside. I did this because in the hatch area of my volvo where it sits under the "floor" is another large chamber that holds the spare/misc storage. Im not sure what the exact process would be called but by doing that it hits way way harder, if I reposition the box anyway or anywhere else in the car its not even half as loud. Kinda weird but Im going with it haha.
EDIT: After typing, reading it, posting and rereading it I came to the realization I may be overthinking the design thing. Should I just go with what I had, change up the port for the tune and double up all my wood and call it a day?