Spare Tire Enclosure?

[Rud]

Hey Kim,

Thanks for answering a bunch of my questions on the phone today, but with answers, come more questions.

Considering that the integra that I have is small, I would love to minimize the space that my box takes up in the hatch. In an effort to do this, i was thinking about building a rectangular box in my spare tire area. The allowable rectangular footprint on the bottom of my spare tire area is 25 inches front to back, and 18 inches left to right. Assuming I build two separate enclosures (1 per sub), this would leave me with interior dimensions of 11x16.5. Which would mean my interior height would be about 8.5 inches, for a little over .88 cubic feet of interior volume.

If i do this...

1) The subs will be facing upwards, is this a problem? I know you said that its a good idea in small cars to have the subs face the back of the car.

2) I might cover up the box with the carpeting that covers the cardboard floor. Would covering my box and subs with this negatively affect the acoustics? I know that I wouldnt cover my home speakers with carpet in the front, but I also realize that having a box in a trunk and having the bass go through the rear seats doesnt necessarily screw bass up either, so Im not sure what effect it will have.

3) I know you said that it shouldnt be a perfect cube so it doesnt produce any standing waves, does that mean that it can still be rectangular, or does it have to have some non right angles (be wedge like)?

4) Should I do anything to reinforce it to keep it from rattling? If it were just a normal box in my hatch it would be sitting on cardboard covered with the carpet, whereas my plan is to have it sitting on the metal shell instead. Should I put carpet down in the trunk to silence vibration caused by the box?

5) And on a side note, did the single sealed box that was built on the website for the 12 inch momo take into account the interior room that the woofer basket takes up? Because it appears that the interior volume is about .912 cubic feet if you multiply the interior dimensions of the box. Of course it is a wedge, and only one dimension is given for the depth, so that might account for the discrepancy. Clue me in?

As I stated to you on the phone, sound is the first priority, and if your experience is that doing something like this will negatively affect my sound, I will just make a box as normal, and just take it out when I need the room. But I must say that I am intruiged by the added security, and room that a spare tire box could provide. Lemme know your thoughts, and thank you for your time.

Ryan

[Kim]

Ryan,
Facing the subs upwards will not present a problem. They will work just fine. Covering the enclosure with carpeting is fine, just don't cover up the subs because this will hinder their performance. You want these to "breathe" freely into the vehicle.
( MO BASS MAN !! )

Regarding the size and shape of the enclosure... with the dimensions that you have listed, standing waves will not be a problem so these dimension will work fine because each dimension is a different length and is not a duplication of another dimension. ( Sounds like we are in a "Time-Warp", It's an Outer
Limits thing!!)

Resonances are sometime the most time consuming things to tame. The first thing is to find out "Who" is making the noise
and at "What" frequencies. This is where dynamat, Cascade Audio, and rubberized undercoating come into play. Stay away from any "spray foam" sound deadening material. This stuff decays and falls apart over time. You might want to use the cardboard cover as a template for a new "version" made out of something a little more dense such as 1/2 or 3/4 inch MDF and
cover it in the same color trunk liner carpet.

Our recommended enclosures do include the driver displacement of the woofers. To calculate the internal volume of a wedge
is to use the following formula; D1 + D2 , divide by 2, then multiply by the height and width and divide by 1728. This will give you the internal box volume.

Keep us posted on your progress!!


Happy Installing!!
Kim, Polk Audio

[puckster]

Hi there,

Just read your post on bluding the sub boxes for the integra spare tire well. I am interested in doing the same thing and was wondering how it turned out for you?

Thanks!

[Airforce1]

just read what ya'll are talking about and there is a site that shows you how to do it. site is
http://www.team-integra.net/sections...?ArticleID=149

[PoweredByDodge]

regarding teh sheetmetal and dumping the sub box into a "metal" well....

chances are, that spare tire well isnt' anything super thick - super sturdy as far as sheetmetal goes.

the polk guys may give you some better ideas, but this is an adaptation of what iwas gonna do to the rear deck of a 76 cadillac when installing a 12 inch IDmax in the rear deck...

ok...

clean out the well and get your box built.. then... get two boxes of dynamat (door kits, the 4 sheet deals) and line the rear tire well with it (double layer)... push it down good and hard so that its reinforcing the metal and deadening the vibration for ya.

then... carpet, finish, whatever your box (i would say do one box with two chambers, that way you dont haave two boxes rattling against each other)... one box with two chambers will be the same to the subs as two boxes)...

finish ure box and before u plop it in, lay about a pound of polyfill in the base of the well... sprread it evenly.. then lay the box on top of that and push it down hard, and bolt it in place with some brackets... this way the box is bolted solid and sturdy but also has enough vibration deadening crap in there to keep you from getting any rattle.