flush mount boxes HELP!

I was just wondering about the flush mount boxes...used in compition cars and such......what I am talking about is were the subs look to be flush where the back seats should be.....better explained it goes all the way from bottom of rear window deck to the floor of trunk.......

My question is this....

Do they leave the subs open behind there or are they using a box behide there?    if they use a box how does sound get back through the wall from the rear window deck to floor?   I hope someone can help......thanks....

All these flush mount boxes have enclosures underneath the facia that you see. They have a fiberglass overlay finish but the box is still MDF enclosures just finished really nice. Infinite baffle systems will not get you very good SPL if you are thinking this route. Go for a ported enclosure and tune the port for the car that your in as well as the subs that you are using.

well Jeff looks like your online tonight to......I still remember days where we could answer everyones questions

so you think I would be better off using a ported box...this is about what I was thinking as well.......I was wondering if you could help me with some designs........I would be willing to call you or we can try to work it out on here     I am running 6  MTX  Thunder subs......yes their old but I cant let them go......space is a little of an issue....im running them in a honda civic......I would like to devide each box with 3 subs.....one box ontop of the other     this way when Im not competeing I can take 3 out.....all 6 end to hurt my ears a little bit...     any suggestions...im using blublux to try to work on this now maybe you can shead some light?

Here is what I am thinking.....each chamber.....20 inches Height....13 inches width...and 16 inches deep....21.56 HZ give optimum on subs......do you have any other ideas?

Here are the spec's ont he subs if anyone wants to try.....

QTS= .670    FS= 37.60HZ  VAS=23.7 LIters  Impedance=12 OHms  Continus power= 250 watts   Cone diameter 9.25 Inches    XMAx= 9.4 MM  Catagory    10 inch sub

Thanks for the help guys....

Hey Jeff, this is my last post tonight so I thought I might give you something to munch on seeing that your probably going to be up all night. Here's a link for some box building figures and how-to's. This is a great site with useful info and see what you like from it: http://www.soundstream.com/heavyweight_boxing2.html