posted
i just put a pair of 15" thuder 7000 woofers in my car, (a 93 buick regal custom), but now the trunk rattles all to hell, and i was wondering what would be the best (and cheapest) way to dampen that, so when i drive down the road, people will hear the bass and not the rattling... i was considering spray damping, and but i don't know how well that works... thanks for any info you can post, or e-mail me at duraiden@yahoo.com
Posts: 1408 | From: Stacyville, IA, USA | Registered: Jan 2000
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Yo. I have a '99 Grand Am. Here is what I did to get rid of the rattles, and like you, rattling was all you could hear outside my car before I did this.
I put at 2 layers of hi-temp mastic on the eniter floor of my trunk, and 3 layers on the trunk lid. On the back of the trunk, I put as much hi-temp mastic as I could fit, but in many spots I had trouble getting just 1 layer due to the complicated metal work. After I did all this matting, I found that the annoying ratlles were still there, BUT this time I could actually tell where they WHERE they were coming from. Now came the most noticeable step toward no rattles.....locating the culprits. After hours of searching, I finally found the most annoying rattle of all, a piece of plastic attatched to the outside metal on the backplate of the trunk. It was hidden by the bumper, and very hard to find. This thing was rattling like crazy. I assaulted this plastic piece with as much mastic as I could, and now it no longer makes an audible sound. The next offender was the liscense plate; 3 layers of mastic silenced it. Then I realized that the pegs under the car where the plastic bumper attatched to the metal were loose and causing the entire bumper to vibrate excessively.....so I put mastic on top of the pegs and the bumper doesn't rattle very much now (but still a little, hittin 140 I can't help it). That was a big step, but I still wasn't satisfied.....my trunk lid is made up of two metal sheets welded toegether at the sides, but in the middle portions of the trunk lid there is a lot of airspace. The top piece of metal was still rattling pretty bad, because I couldn't use mastic on it (unless I dynamtted the exterior of my car!) due to the fact that there was another metal sheet covering it up. So, I went to wal mart and bout a 3 dollar can of rubberized under coating. I stuck the nozel of the spray can in the various holes in the interior metal that allowed me acces to the exterior panel and unloaded the full can into that airspace. the lid of my trunk no longer rattles. period.
Finally, since the rubberized under coating worked so well, I bought another can and used it all over the back part of my trunk (where I could only get 1 layer of mastic earlier). My trunk is pretty damn quiet now, but it was a lot of work.
By the way, to apply the mastic, I used a black and decker heat gun ($30), and a wooden 1" wallpaper roller from Home Depot($4). Make sure you use a WOODEN roller and a heat gun. I tried using a plastic one and it broke quickly. Also, I replaced the air vents in my trunk with mesh grill cuz the flaps on the factory ones were making a really loud flapping sound.
And oh yeah, I have taken the factory rear deck out because it was moving up and down severely, and as a result, rattling severly. I plan to make a new one out of MDF and grill cloth ASAP.
And oh yeah, it is somewhat redundant to use the spray and mat in the same area. Whenever possible, use the mat. It is cleaner and easier to control. Use the spray for inaccesible areas. If you need more damping in an area, just use more mat.
Have fun. And be sure to roll down your windows while your bassin.....
Posts: 156 | From: Austin/Kerrville TX USA | Registered: Jan 2000
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The best thing to do would to figure out exactly where the rattles come from. I put two 12 in. mtx 3000 in a nissan and the trunk ratlled like a bitch figured out is was the license plate, a heat sink that separates the exhaust heat from the trunk, and his rear deck. Then you decide what to use.
Posts: 272 | From: Tyler, TX, U.S.A. | Registered: Jul 1999
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Here's what I posted in a different thread....
Have any of you guys tried non "Dynamat" brand dynamat? There is some stuff available from www.mcmaster.com that is exactly like dynamat, except it doesn't have Dynamat silkscreened on it, and it's about 1/6 th the price. (12sq feet for 12.79, instead of 2 sq feet for 12 bucks) You'll find it on page 3040, just type 3040 into the search box on the main page. Once the page loads, it's at the very bottom, part # 9709T18 . The stuff you're looking for is called High Temp Mastic. It does work, lots of people on the Elite Car Audio forum ( www.elitecaraudio.com )have used it. They also have something similar to CAE's Vblock VB-2 I think. It's in the same place as the high temp mastic, but it's called visoelastic, part # 9709T26 . For that stuff, you can get 9 sq feet for 22.50, instead of whatever VB-2 costs.
posted
The easiest way to control trunk rattling is to direct all of the energy into the interior! If you don't pressurize the trunk it won't rattle as much!
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
The Big Show The Dukk says: Know your bass: PORT your damn box!! Have HoleSaw, Will Travel!
posted
well hopefully that's the problem - my subs are louder with the trunk open (hehe). oh well, thanx for the help, guys, and I'll tell ya how it works.
Posts: 1408 | From: Stacyville, IA, USA | Registered: Jan 2000
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I've used the high temp mastic and it is the same thing as dynamat, I recently used both in the same day on two different cars. If there is a difference I sure can't tell. Also I think Parts Express sells the same stuff.
quote:Originally posted by Dukk: The easiest way to control trunk rattling is to direct all of the energy into the interior! If you don't pressurize the trunk it won't rattle as much!
Dukk, this sounds like the typical sedan syndrom. If the subs face backwards, direct their energy using a board on the inside of the trunk, allowing air to escape towards the front. And if you can, duct it through the rear deck. And the next question is...."How do you do that"? Any takers?
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E.C. Wuz here
Posts: 1057 | From: Vancouver, British Columbia, Canada 'eh | Registered: May 1999
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yes, dukk, they are facing forward. i'll try facing them backwards, but I don't know how they'll sound... I heard somewhere that facing them forwards hits harder, but facing them backwards makes em sound deeper... oh well
------------------ anything but rockford fosgate, PLEASE!!
Posts: 1408 | From: Stacyville, IA, USA | Registered: Jan 2000
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posted
You could always put roofing material in the doors or if you are desperate concreate the doors? Just kidding. I am going to try putting expanding foam in door panels. I think that It might do some good.
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