Hey all, I finally got my subs in to find out how Lancers trunk lid handles 800rms of power, well all i have to say not so good, it shakes like a sheet of paper, rear deck is about to jump out and break in half at that kind of power. I turned down subs down to 400rms interior sound quality is fair but not the best since that rear deck plastic piece still rattles sometimes.
So here I came to the point where I need to soundproof my trunk and rear deck, what are the options out there?
Since I don't have a big budget what is the possible best way to go?

just ordered 100 sq.ft of 50mil fatmat, at a pretty good rate of $1.30 per sq.ft. will start to work on the trunk in the next few days.
Going to post an update soon how install went and what needs to be insulated and with how many layers. (IMG:style_emoticons/default/thumbsup.gif)

Let us know how it goes.
I hate how the trunk rattles. Even with the Rockford upgraded system on the GTS, it's annoying. I'd like to do this one day too, when I have money.
I suggest you do your door panels too.

well i finally got to do the trunk lid yesterday, no pics so far since it was almost night time and would be hard to see, well it's a straightforward job anyways.

I got to insulate the trunk lid itself, when you take off the cover, you can reach with you hand to almost whole surface of the vertical part of the lid.
Also I covered the interior surface of the trunk lid covering most of the openings, so it was sort of a double layer 100mil insulation (IMG:style_emoticons/default/tongue.gif)
Btw there is more than enough surface to insulate so the factory cover fits right back without any problems, so it looks stock completely, except for the trunk being so heavy that it can chop you in half.
Well there is less rattle, but the bumper is the most annoying part of the car, I believe it will stop to rattle with the full trunk insulation.

I started on the rear deck, pulled off all trim parts including parts of rear seat and a deck itself, guess what almost no interior rattle on full volume at 400rms
only minor distortions are noticeable, well I guess it's impossible to get rid of them completely. Pics are coming of the rear deck removal, and insulating process.

So here is the first part of the project

#1 Trunk lid: -25% exterior rattle

#2 Rear Deck: -90% of interior rattle (maybe)

I have never heard of Fatmat, let us know your thoughts.

One company i can vouch for is Elemental Designs. They have a variety of sound deadening products, from liquid/paste type to rolls of stick on materials with difference thickness.

Check it out:
http://www.edesignaudio.com/index.php?cPath=1_24

I got a 1000 watt amp with a 10" sub (imma put the other way in later) but it rattles like crazy... i made my own custom box and it has little air leaks in it and i noticed it was the inside of the car that was rattling... it was the plastic behind the back seats. i put two black t shirt (yea im a poor college kid) between the plastic parts and the window i squished it in there where they meet and it stopped the rattling (IMG:style_emoticons/default/smile.gif) ... imma have to change that but its a temporary fix (IMG:style_emoticons/default/smile.gif)

Okay I did the full trunk insulation with a 50mil one layer only (no pics since my memory card got damaged)

Rear deck is an easy one:
You will have to pull off part of rear seat in order to get the deck off (non moving part of the seat tho (IMG:style_emoticons/default/smile.gif) ) as well as gray plastic covers on both sides of the pillars
Be carefull there is an airbag behind them.
I insulated all metal areas on the deck, as well as the plastic deck itself. Just cut small pieces and fit them wherever possible.
To prevent the plastic piece from hitting glass you go and buy foam insulation with a sticky side, I think it's used for door and window insulation and is sold even at dollar stores.
Trunk i just did with one layer and guess what there is still vibration mostly from outside parts like bumper that just vobbles and hits the frame, and heat shield above the muffler creates a good amount of vibration. I will probably end up doing another layer and see how it goes, but I'm pretty sure i will need another 2 - 3 layers to make it quiet at mid volume.

Overall it's a great mod to improve sound quality, I guess doesnt matter what you use fatmat or other products, just don't pay too much for overpriced dynamt, since all it is a foil with a layer of tar.

There are many options. Of course tar works but it stinks and is nasty to work with. Parts express many times has buyouts on dynamat competitors. Anything that will dampen sound will help. Rubberized undercoating, blankets, wood, liquid nails, silicone caulk, sheets of rubber etc. If you are strategic enough well placed small squares of dynamat works well too. Remember your goal is not necessarily to cover the panels but to stop or at least transfer the rattle to some place less annoying. When I was on a budget with my first car. I gutted my trunk put on hearing protection and crawled in there with the sub up loud enough to cause rattles. By pressing on different places you can find where you need to place the squares. By using this method one box will go a long way. When you are finished replace all the factory pieces overtop of your matting.

Here's a tip for you that may be free: My 1g eclipse had a 12 pound rubber mat covering the entire firewall. If someone is gutting their interior they will probably give it to you. Trimming this mat to fit your trunk would dampen alot of vibration.