LGT4u2nv Posted November 30, 2006 Share Posted November 30, 2006 The situation: I want to install a sub in my car, but I don’t want to give up any trunk space. A friend gave me a 12" rockford fosgate sub that they are no longer using, so I'm trying to find a way to use that. I know I can't make a box big enough to fit on top of the spare tire due to volume and mounting depth. I want to keep the spare tire and tools in the trunk. My Solution: I will remove the current, loose fitting, trunk floor that covers the spare tire. I will make a new floor out of MDF and mount the sub to the under side of it. There is enough mounting depth if the sub is centered on the spare tire. I will make some new brackets for the jack and tools on the underside of the new floor. I will put a rubber seal strip all the way around the spare tire well to actually seal the new floor to the well itself. I will put a protection grill over the hole in the floor where the sub is and carpet the entire thing to match the rest of the trunk interior. This way, the entire spare tire well becomes my sub box and should provide enough volume for my 12” sub. I know I need to fasten the new floor down, but I haven’t quite figured that out yet. I think I can tie it down to the spare tire or the spare tire tie down point. I could use some suggestions in with respect to that. Link to comment Share on other sites More sharing options...
lucas569 Posted November 30, 2006 Share Posted November 30, 2006 lots of work imo, would u consider this? http://cgi.ebay.com/Subaru-05-Legacy-GT-Subwoofer-Enclosure-Sub-box-Pass_W0QQitemZ140057038908QQihZ004QQcategoryZ50565QQrdZ1QQcmdZViewItem it comes in 12" too! Link to comment Share on other sites More sharing options...
LGT4u2nv Posted November 30, 2006 Author Share Posted November 30, 2006 For me, a fiberglass corner box would be a fall back, not a first choice. I've seen 12" corner boxes and they don't fit as snug into the corner like a 10" does. I think I would have to buy a 10" if it came to that. Link to comment Share on other sites More sharing options...
16psibrick Posted November 30, 2006 Share Posted November 30, 2006 click the link labled install log in my sig and see if you can get some ideas Link to comment Share on other sites More sharing options...
Boulderguy Posted November 30, 2006 Share Posted November 30, 2006 Your proposal isn't a bad idea but if you're serious about your sound it's frought with problems - sealing, wiring, hinging, access to spare & most of all box tuning Vas. All those can be overcome with some work but it won't be easy. But before you go there ask yourself if it's worth taking all that on just for a free sub. You can get the same results from a ten if it's done right & go with the corner 'glass box. Easier, trick-er, better SQ, sell-able, etc. Good luck. Link to comment Share on other sites More sharing options...
JuxtaGT Posted November 30, 2006 Share Posted November 30, 2006 Just posted about another ebay option to no responce, might look at these too and save yourself some work. http://stores.ebay.com/duffman-audio Same idea, but a DIY would save money. Link to comment Share on other sites More sharing options...
LGT4u2nv Posted December 1, 2006 Author Share Posted December 1, 2006 my sub needs 1.25 to 1.5 cu ft, so that box wouldn't work for me. However, you guys are probably right to just buy myself a 10" and build a box like the ones in the ebay store from duffman audio. It would be a cleaner, more self-contained solution. I appreciate your opinions. Link to comment Share on other sites More sharing options...
JuxtaGT Posted December 2, 2006 Share Posted December 2, 2006 No worries man. Let us know what you decide to do. I myself am leaning towards a DIY version of the Duffman box. Won't happen for a while though, holidays are damper on such things. Link to comment Share on other sites More sharing options...
NSFW Posted December 2, 2006 Share Posted December 2, 2006 Cool idea. Seems like you could get close to double the space of the Duffman box using your proposal, since it would incorporate the corners of the well, the space under/around the tire, etc. That should add up to about what you need for that 12. It would be tricky to make it seal well against the car and also be removable so you can get to the tire (if not to fix a flat, then to check the pressure once in a while). Seems like a solvable problem, but I admit I don't have the solution... But, thinking out loud: If you use RTV silicone to fill the gap between the MDF and the sheetmetal, you'll get a better seal than just a rubber strip. You'd want to put aluminum foil or something over the metal when you apply the RTV, to prevent it from actually sticking. From under the car, can you get access to the trunk floor sheetmetal around the tire well? Suppose you drill holes for T-nuts - a center hole and three small holes for the prongs, for a nut at each corner. Push the T-nuts up from below, then bend the prongs over so they don't fall back out. Then sink bolts into them from above the MDF. Use fender washers and perhaps epoxy to distribute the force and discourage cracking. Keep a wrench/screwdriver/hex-key/whatever in the car so you can remove the whole thing when you need to. I'm thinking out loud, not making promises. The whole thing does sound like a pain. Link to comment Share on other sites More sharing options...
16psibrick Posted December 2, 2006 Share Posted December 2, 2006 cut a whole in the bottom of the spare tire well and build an AP box thats barely bigger than the sub itself FTW! Link to comment Share on other sites More sharing options...
LGT4u2nv Posted December 3, 2006 Author Share Posted December 3, 2006 Even though I've pretty much convinced myself to abandon this idea, I have figured out a few more issue in case anyone else wants to give it a go. First of all, it would be near impossible to seal the top face of the box against the horizontal sheet metal portion of the trunk that surrounds the tire well. That metal is all kinds of not flat. I would actually take a piece of 1/2 inch MDF to make the new floor and a piece of 3/4 screwed to the bottom side of it to fasten the sub to. The 3/4 piece would be cut to the exact same shape as the tire well so that it actually fits inside and seals against the vertical walls of the tire well. This way, it doesn't matter how irregular the profile of the tire well is, you just cut the second layer to match. You might even need to make just a ring as a third layer to have more surface area in contact with the sidewalls of the well. In any event, it would be quite easy to get a really tight fit for the seal that wouldn't require a lot of force to hold the whole thing in place. Now, to hold the new floor down, I would utilize the spare tire. I would take another piece of 3/4 MDF 14" dia and drill the same hole pattern you see in the spare tire (center hub and 5 lugs). I would bolt it to the spare tire and then tie the tire down as it usually would be. Now, you basically have a piece of 3/4 MDF attached to the floor of the tire well and a lot of real estate to attach tie bolts form there up to the new trunk floor. Counter bore the top 1/2 MDF so the nuts sit flush with the rest of the floor. You could even use wing nuts so no tools are required to take this thing out. Link to comment Share on other sites More sharing options...
Boulderguy Posted December 3, 2006 Share Posted December 3, 2006 Take it a step further - you'd need to use at least 3/4" MDF or better 7/8" as the mount surface to provide a stable surface - 1/2" would not cut it. Then keep in mind that whatever you use to seal the edges will raise the MDF even more. So now your new floor piece is considerably taller than the surrounding floor - uck. Link to comment Share on other sites More sharing options...
LGT4u2nv Posted December 3, 2006 Author Share Posted December 3, 2006 You know what they say about pictures...this may help explain my intent. The new floor will not be any higher than the surrounding floor. Link to comment Share on other sites More sharing options...
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