sound proofing

[color=red]I have 2 12.1D dual voice coils subs in my 99 alero, and I get alot of rattling from the trunk and from inside the car. Something is rattling in my dash board and i can't figure out what it is. It comes from the right cornernear the windshield. What do u think it is and what do u recommend doing about it?

[j{}n]

turn the volume down


j/k, dynomat my friend. that, or stick a pack of cigs or styrofoam behind the license plate

Ya thanks I already used dynomat on the trunk. The main rattling is in the dash board and i want to know if anyone else had the same problem and waht they did.

ive never had this problem, but my guess would be to take out the plastic defroster thing at the front of the dash (just pull it out) and re-install it. It sounds like it is no fully popped in

My dash rattles too. The first problem was the plastic piece on the inside of the outside of the instrument panel. That was just a screw. Right now, it sounds like the passenger airbag cover is rattling, but it may be the defogger thing. A penny in the center console will drive you crazy too.
As for the trunk, good luck. I just gave up on that. One of these days I'll tear it all apart, but it's not that big of a deal. Just turn it up so the bass covers the rattle.

[b-spot]

^ yeah, but then you sound like a fool whenever you drive through a parking lot.

Expanding foam/weather stripping will take care of most of the trunk rattle, but there is still a bit that is pretty much impossible to kill without alot of effort

[vulgar]

^very true. I used packaging foam to kill the rattle in the plastic piece that says "alero" on it. Dynomat didnt really do much. I then put weatherstripping down where the trunk meets the bumper and that cut out a lot. It seems the only thing that is left is some deck rattle. Im thinkin about expanding foam for that but I honestly dont think itll do much

I try not to sound like a fool. I usually only really boom when I'm fishing for po' (there's a sound ordinance where overdrive lives, but how would I know?). I got rid of all the trunk rattles I could find, but there's one that just won't go away. I might have to try the packaging foam, 'cause I think that's where it's coming from.

[b-spot]

Fishin for po'?? wow.. you sure must be hard to the kore. I heard breaking those sound ordinances can land you in the big house... :rolleyes:

And if you haven't killed that rattle that vulgar mentioned (the two panels just behind the plate) you sound like a fool. I could rattle that thing running 6x9's even before i got my system.

Haven't caught any yet... They're just asses around there, so it'd be fun to do nothing wrong and get harassed. Overdrive has gotten Hondas pulled over with the bass in his truck. Not discriminating at all...

I know I sound like a fool, that's why I keep it turned down most of the time.

yeah good luck with the trunk rattle... yeah it sounds like poop from the outside.. but who cares.. it sounds badass inside and thats all that matters

[b-spot]

Originally posted by crazykid@Dec 1 2003, 12:59 PM
yeah good luck with the trunk rattle... yeah it sounds like poop from the outside.. but who cares.. it sounds badass inside and thats all that matters

Naw.. its no good to be getting laughed at cruising down the street or through a parking lot cuz it sounds like your trunk is falling off.

misslindseysue.. get the foam. best $3 investment you can make. Then you'll have hondas pulled over left and right and they'll have no idea its you. I can't believe they pull you over for systems.. i heard of people having cops see their lisence plate moving and pull 'em over. pretty gay if you ask me.

only way u can completely get rid of that rattle is to take there liscense plate insert out..... weld a sheet of this metal in there..... then mold the insert into the trunklid. then dynomat the underside of the trunklid.

other than that u just have to deal with the rattle.

u will almost never be able to get rid of all the noise that u hear when ur outside of the car. but soundxtreme gave me the best solution..... "just build ur system loud enuff so u cant here poop inside the car" this solution worked for me....

[jackal2000]

i noticed my system sounds better when i fold the back seat down. anybody else notice this?

[vulgar]

of course, open air always sounds better...youre talking about subs right?

You'll also get louder boom if you move the subs toward the back of the trunk, so that they fire right into the back and bounce back to you. Overdrive's brother has his firing right into the floor of his truck (on a little stand), and they're hella loud. You can tell the differece if he flips them up.

i'm getting a rattle from underneath the middle of the car. it sounds like something small just from the light tone, but i have no idea what it is. as for the license plate i just put 4 screws in instead of the origional 2.

[Pimpalero03]

heat sheild thingy on the exhaust. mine did to

stuffing some 1/16" thick foam into the gap between the plastic housing with "Alero" on it and the trunk lid got rid of the rattle there for me- give it a try.

[knowledge8069]

This is a full write-up of how to silence most of an Alero's common trunk rattle points.

I had to do two things to silence the rattles from my trunk.

1. Silence the license plate panel.
2. Prevent the trunk's exterior sheet metal from resonating.

Here's how I fixed my trunk rattles.

1. Installed rubber washers and rubber gasline between the license plate panel and the sheet metal that it attaches to.

The washers should be fairly thin, maybe 1/8 inch. They can be glued to the back of the license plate panel. I used 4 of them, one in each corner of the center section.

I also took a piece of rubber gasline, split it down one side, and wrapped it over the top edge of the license plate panel. The hose runs the length of the edge, from tail light to tail light. I then pressed the panel firmly back into place, wedging the hose between the panel edge and the upper trunk section.

Note: My car is black in color, so the gasline does not stand out against the paint. If you have a different color Alero, it might be possible to paint the hose section. The gasline fix made a huge difference. Weather stripping is also possible, but tends to decay over time.


2. Covered all of the trunk with Dynamat Xtreme.

I know that many people will not want to spend the money for Dynamat. In my car, the bass was causing some underbody parts to rattle, most of which were pieces directly under the trunk. The outside sheet metal also vibrated. This fix was essential for my trunk, but may not be for others.

Applying Dynamat to the floor of the trunk, including under the spare tire, silenced the underbody rattles. Applying Dynamat to the rest of the trunk resulted in almost complete silence outside the car, as far as rattles are concerned. Also, the bass is just as loud inside the car, but now it is almost silent outside.

It took an entire Dynamat Xtreme Bulk Kit (36 Sq. Feet) to cover the trunk. This will cost about $110 dollars on Ebay.

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In addition, the bass is much cleaner inside the car. It is more defined, rather than fuzzy because of resonating metal and plastic pieces. I still have some rattle in the rear deck, which I am working on.

As jackal2000 mentioned above, folding the rear seat down makes a difference. When my bass hits with the back seats up, it forces air up into the backs of the 6x9's, making them kick with the bass. This is not a good thing, as it distorts the midrange. I am working on cutting a bass port in the rear deck so that I can have the seat up in back and still have good, clean bass.

A few interior rattle fixes:

1. Make sure the screw holding the rear view mirror to the windshield is tight.
2. Wedge something between the rear carpeted deck piece and the rear window.

Good Luck!