would this be a good idea?

[blakgtp 10+ year member]

hey. So like everyone else, I hate being "that guy" with the rattling trunk. So a few weeks ago I faced my sub forward (sundown sa-15) and "sealed" it from the trunk temporarily with mdf and old clothing..etc. I noticed a slight gain in loudness and my trunk rattle almost completely disappeared. The only problem was I noticed a great reduction in the low end frequency authority ( guessing, it's because it's not loading off the back of the trunk anymore). So now it's facing the back of the trunk again, and the trunk has the annoying rattle whenever i decide to get a little loud. I can't hear the rattle from inside the car, but outside it's pretty bad. So I'm wondering which route I should to resolve my problem. (trunk lid and part of the trunk surround is already deadened) (the vibration seems to be coming from the rear bumper even though all the bolts are tightened.)

option 1: Buy A LOT of sound deadner and mlv and just go crazy with it.

option 2: Face sub forward and seal from trunk again. and use eq to boost the lowest frequecies (not sure if this would work well or not)

option 3: build a "barrier" between the sub and the back of the trunk, to act as a reflective surface and to block sound waves from getting to back of car

kinda like this:

Click to read more...

 

[*Ace* 10+ year member]

I wouldn't make any kind of barrier, but that's just me. Anyways, I personally would just go with the sound deadening.

I bought 37.5 sq. ft. of RAAMmat BXT II and about 114 sq ft Ensolite IUO Peel and Stick from RAAMaudio - Automotive sound deadening products for about $130 before shipping and am very happy with it. I have covered both my front doors, front door panels, as well as the complete trunk and lid and I still have a few 1.8cf sheets left. I put the Ensolite peel and stick on the body of the car where the trunk lid contacts it when closed. When the trunk is closed you can't see the ensolite and it has eliminated just about 100% of the rattles that came from the trunk.

Just remember to only use about 25% coverage of BXT on the parts you sound deaden. I went a little overboard and put about 50%-75% coverage, but I had extra to waste anyways.

 

[Bettr n' Revrse 5,000+ posts]

Sure it isn't the license plate?

 

[blakgtp 10+ year member]

I wouldn't make any kind of barrier, but that's just me. Anyways, I personally would just go with the sound deadening.
I bought 37.5 sq. ft. of RAAMmat BXT II and about 114 sq ft Ensolite IUO Peel and Stick from RAAMaudio - Automotive sound deadening products for about $130 before shipping and am very happy with it. I have covered both my front doors, front door panels, as well as the complete trunk and lid and I still have a few 1.8cf sheets left. I put the Ensolite peel and stick on the body of the car where the trunk lid contacts it when closed. When the trunk is closed you can't see the ensolite and it has eliminated just about 100% of the rattles that came from the trunk.

Just remember to only use about 25% coverage of BXT on the parts you sound deaden. I went a little overboard and put about 50%-75% coverage, but I had extra to waste anyways.

sounds reasonable. I didn't want to deaden the trunk if it would still have considerable rattle. but i guess i'll give it a try

 

[blakgtp 10+ year member]

Sure it isn't the license plate?

yes, that was one of the first things i fixed. put deadener behind it

 

[blakgtp 10+ year member]

has anyone else experienced my problem with facing the subs forward and losing some lows? Is it just because there was clothing used to seal and they didn't create a reflective surface for the waves? or should i build a box that's tuned lower for forward facing? it's tuned at 35hz right now

 

[bgowdy 5,000+ posts]

honestly man on a trunk i dont think anything really can be done about the rattle when the sub is loading off it. even with sound deadener. thats like with my blazer hatch, theres nothing i can do about the annoying *** rattle

 

[*Ace* 10+ year member]

sounds reasonable. I didn't want to deaden the trunk if it would still have considerable rattle. but i guess i'll give it a try

The thing that helped my rattles go away the most was the ensolite. The rattle you hear is the trunk lid bouncing up and down off the body of your car. When you put the ensolite between the two, the trunk lid still bounces up and down but the ensolite absorbs all the force and the rattle goes away significantly. If you want just buy the ensolite first and try that. It's much cheaper than the deadener.

 

[Iosias 10+ year member]

If you have a local rubber supply chain near by some Closed Cell Foam would do the trick aswell. 1/8 or thicker would work as well as Ensolite.

 

[blakgtp 10+ year member]

it's wasn't trunk lid because it has two layers of sound deadener on it. and when i hold it down with my hand nothing changes. however, when i hold the rear bumper down the rattles stop. So i did some deadening today and found that there's openings at the back of the trunk that go into an air chamber where the rear bumper is. Sealed those off with some board and deadened the area. havent tried it out yet, but i have a feeling this will be a good improvement

 

[brooklynjoy2008 10+ year member]

I used 2 cans of spray foam on my old car. You could also pull the bumper off and do behind it. When I was done I only had a slight rattle, but in the car u couldn't hear it even with the back seats down.