Hi all.....ok, so over last 2 days have dismantled entire hatch of my 2000 ITR and am re-doing much of it. A while ago removed spare tire and (2) Arc's are counter-sunk into that area. I've got a false floor above that to which my sub box was currently screwed into. The false floor has 2x2' opening or so right above where amps sit......10" fluorescent lights are installed on underside of false floor and light up amps..

My false floor though is basically sitting sitting on hatch sheet metal....the false floor is simply wedged below upper sway bar in hatch and there's some totally flimsy 3' x 2" brace that is about 6" from rear seats to which the false floor was previously screwed into.

Needless to say, I'm not that enthused w/ how things are mounted. I have one main goal and that is to totally (or at least very close) de-couple my sub from its mounting surface so I'm not transferring energy to other surfaces in my attempt to ELIMINATE vibrations. Cabin of car was guttted and 3 rolls placed on basically everything other than roof, have a Dynamat trunk kit and (4) door kits that I've cut-up and placed throughout hatch, sheet metal around tail-lights, etc. But is still not quite enough which is why I'm trying to de-couple sub and additionally add more deadener in hatch.

I have one dilemma/question.....I bought 2"x2"x18" oak pieces and plan is to mount false floor to the oak piece 6" or so behind rear seats and the other right along rear hatch that still allows access to upper sway bar in hatch. To de-couple subs from hatch floor and false floor I plan to use (3-4) 3x3" pieces of dynamat at each location where a screw is located......both screws from sub-box to false floor and again from false floor to hatch sheet metal.

I'd love to simply weld a couple L brackets to hatch floor so I have a solid mounting location to which oak pieces can be affixed. But, I don't have a torch/welder at my disposal.

Unless I decide to rent one I'm stuck with mounting oak pieces to hatch floor and at the moment can't really think of anything other than some long sheet metal screws going through oak into the sheet metal hatch floor. But I'm a bit worred about what is under the sheet metal that starts just in front of tire-well to the rear seat....I don't want to puncture a hose line/etc. that runs directly below the hatch floor.

Sorry for extremely long post.......FCM/B18/others........thoughts/comments/disagreements to what I'm trying to accomplish + what is below hatch sheet metal?

thanks
And as a side-note.....I'm a bit **** and maybe to some degree a bit too theoretical but I am a fan of over-building things and doing things that are somewhat unique but are functional as well. I've actually thought about re-routing one of my air-conditioning ducts to rear so my amps will stay cool in summer. I cringe when my amps shut-off during summer when I'm pushing the system and even though I know the protection circuitry cuts-off at a point before amp is damaged I still don't even like the thought my amp is getting to this point.


Modified by thekid03 at 2:26 AM 12/30/2007

 

If you want to mount something to the sheet metal, like welding a piece of metal] use a sub-floor adhesive, available from Lepages, and Bulldog at any building supply store.
EG; if you want to attach your 2"x2" oak to the sheet metal, sand/cut/notch the surface of the oak that will be in contact with the sheet metal to fit the sheet metal surface as close as possible and so you get the proper angle on the "top" of the 2x2, once 2x2 fits the way you want it use a felt pen/marker to trace out the "footprint" of the 2x2 on the sheet metal, run a 1/2" bead of adhesive the full length of the 2x2, [onto the sheet metal] press the 2x2 into the bead onto the sheet metal, press hard then lift 2x2 up 2"-3" allowing air to get to the adhesive, press 2x2 back into place, in 24hr the 2x2 will be part of the car, and no screw holes in the floor pan.
A/C to cool the amps, been there done that and it works great, but lots of work to do it right, you can also get good results with a push/pull fan setout, a fan or fans pushing fresh air into the enclosed amp rack, another fan/fans pulling the hot air out of amp rack, fan(s) are placed at opposite ends of amp rack so fresh air is pushed/pulled over the amps and out of the amp rack, a thermo switch can be placed on the sub amp to control the relay that runs the fans, that way they are on only when needed. 94

As for the sub box, it should be mounted to as solidly to the cars chassis as it can be.
The more mass a sub box has the better it will sound, if you can add the mass of the car to the mass of the sub box the subs will sound as good as the box/amp and tuning will allow.
Although the box will resonate, very little of the rattling you hear comes from the box, it comes from the air being moved by the sub.
Isolating the box will not get rid of the resignation, in fact it will make it worse adding mass will dampen it and get rid of some of the resignations.
It is the reason spare tire well fiberglass and MDF sub enclosures sound so good, the enclosure is almost part of the car.

If you want a demo of this, place the sub box on the floor, [garage floor] turn on some tunes, adjust bass and volume to get the best sound, as your listening to it have someone sit on the box, 2 people if the box is big enough, you will like what you hear. 94

 

ahhhh......mounting 2x2's to floor....hadn't thought of that....consider it done. One other question......although I am expecting most rattles to be eliminated or reduced, I've got a vibration in rear bumper between wheel well and rear of car. I'm just not sure it'll go away....hope for the best but am not necessarily planning vibration will stop. If it still rattles once I re-install everything I'm wondering if I could clean the inside of lower plastic piece and with a strong adhesive adhesive like JB Weld, affix sound-deadener to the plastic piece.

Would this stand up to water, heat into the upper 90's, cold down to 10 degrees, average humidity of around 30-40% as well as sand and de-icer used on roads during winter?


Anyway, I thought it might be beneficial to attempt to de-couple sub from false floor....with that said though once I pulled out the false floor realized it was particle board and had basically snapped in half. In regards to de-coupling I suppose my thinking was along the lines of the speaker spikes and why they're used. . I've never done an A/B comparison with and without spikes but I can understand the logic....not sure it'll work in car but guess I'll try anyway.

I bought some 3/4" MDF to replace false floor.....I actually bought enough so I can double up the MDF and end up with a 1.5" false floor.....kinda overboard but it won't take that long to cut 2 pieces.

Box weighs 36 pounds....with (2) 10w7's I'm looking at a almost 100 pounds. Box is internally braced and speakers screw into a baffle made of (2) 3/4" MDF boards glued & screwed together.....the box is about the only thing my 2nd to last installer did right.

I don't care how long it takes but I'm hell-bent on finally having an install that I'm proud of and most important of all an install that designed with the sole purpose of SQ.