Ok, so about a week ago I got my final system installed, except for the amp. Now when we were playing with it and just playing some music the rattle wasn't too bad but I put a layer of Stinger Roadkill on it and it helped a bit.

Fast foward to this evening.

I was demoing for some friends and I haven't had bad rattle yet until now. My trunk lid is now slapping and it's getting ugly. My setup is sub up port back so basically this sub is firing right at the trunk lid. So on a good note, this sub is moving enough air and creating enough pressure to begin to damage my trunk. On the downside, it's damaging my trunk.

Question:

Would another layer of deadener help with this? Or am I basically screwed at this point? I know when I have a setup like this the trunk rattle is inevitable but can I help dampen it enough to take away some of the rattle. I have a five gallon bucket of R-block liquid sound deadener and some more sheets of roadkill so I am thinking of applying another layer of both.

It Could Be Sufficient Enough To Stop Damage, But I've Never Used Either Product So I Can't Really Tell You.

All These People Talking About This And The Threads On It Are Seriously Making Me Happy I Don't Have A Trunk Car For Any Car Audio Application.

Rattles aren't helped by deadener, tightening the hinges and putting something like a foam of sorts between the rattling surfaces can though.

Well there isn't much I can do with the foam seeing as there is foam weather stripping all along the edge of the trunk and it is still slapping. I will try tightening the hinges though. I just don't want to fuck anything up too bad that I end up honestly destroying my trunk lid. Especially when I am putting extra power on the sub once I get my other amp in there.

Dude I have the same problem.

I have a 15" SSD firing up towards my trunk lid and my trunk slaps so hard.

Until I can get some deadening in there and find something to stop the lid from slapping the frame I have to deal with it.

You guys have designed systems that exceed your vehicle's ability to host them - too much pressure in too little space. The trunk lid seal is the path of least resistance for the pressure to escape. You either have to turn it down or make some drastic changes to reinforce the trunk. I'd reconsider the system design. What you're doing now is like running an air conditioner with the windows open.

Well there isn't much I can do with the foam seeing as there is foam weather stripping all along the edge of the trunk and it is still slapping. I will try tightening the hinges though. I just don't want to fuck anything up too bad that I end up honestly destroying my trunk lid. Especially when I am putting extra power on the sub once I get my other amp in there.

And the factory foam is pretty useless from the get go. If you want it gone you will have to do more than just slap something near it.

wall time

///M5 what do you suggest? Like what kind of product do you suggest I purchase to help out with the problem? And a wall isn't an option seeing as I am running this in a sedan and walls in sedans in my opinion just look stupid. Would possibly flipping the box around to aim the port at the cabin help a bit seeing as the air from the port will have an easier path into a more open space? I have been thinking about rebuilding my box to build it inside the trunk so I can get enough height to put the sub on the front of the box. So possibly just rebuild and have the sub and port firing into the cabin. That will force all of the pressure towards the cabin instead of the trunk lid.

But yeah, ///M5, help on what kind of foam material to use would be awesome. Like the second skin luxury liner closed cell foam, is that what you are referring to or something else?

Other than turning it down there is no generic answer but with some more info on what you have, how it is installed, what kind of car, some pics/vids etc. it gets easier to help.

Try venting into the cabin better.

Other than turning it down there is no generic answer but with some more info on what you have, how it is installed, what kind of car, some pics/vids etc. it gets easier to help.

Well it all the equipment is in my sig except I am running a BXI2610 instead of the RD amp. So for how it's installed, the sub is firing up and the port is firing back. So basically the sub is firing right at the trunk lid. I am thinking about rebuilding the box and firing sub and port into the cabin to help with it, since that should take care of most of the rattle I would think since the pressure would all be getting forced into the cabin. But basically with the design right now I am fucked so some of the closed cell foam kind of lessen the impact at all?

Building a new box would help, and its what I'm doing very soon.

I have to cut the trunk lid supports but I will be able to fire sub and port towards the cabin hopefully resulting in less trunk slapping.

Edited July 6, 200916 yr by ShaneSauce

You're not moving air, you're exciting the air, so driver/port orientation will be of little help. You will still be pressurizing the air within the trunk just as you would if you kept the same application.

The only other thing I could think of is to line where the trunk opens with some kind of adhesive foam...

Which is why I am thinking putting some of the open or close cell foam over that. Oh well, I will figure something out. Another layer of the deadener tomorrow, then gonna put some deadener on the doors to use up my bulk pack. I might take out the back seat and get those damn 6x9s out and allow some better air flow.

Fire everything to the front and seal off the trunk. Bye-bye trunk rattles.

Blah, well I guess when I get some more cash coming in, it's time to rebuild the box and re-run a bunch of wires. New trunk rebuild in the future. Until then, I need some suggestions to slow the damage to my car. Not a permanent fix, just something to slow it down.

If your rear seat backs fold down, try it with one side open and see if that helps.

Fire everything to the front and seal off the trunk. Bye-bye trunk rattles.

Ah you posted what I was going to say. That'll give you less airspace to pressurize as well, so it may make it louder. Otherwise you probably just need to mass load the trunk lid. Maybe glue some bricks to it, haha.

Yesterday i use three cans of plumbers expanding foam, did it work wonders until i get some deadening. First I open the trunk and use about a can and a half just for all the gaps between the two metal trunk frames on the lid. Then I used a whole can between my outer trunk skin(plastic panel or whatever its made from) and the metal frame its attached to (this achieved the best results since thats were the biggest gaps were, and my trunk closes without that hollow sound now) its sounds like my trunk is a solid heavy piece instead of the lightweight sound it had earlier. Then I used the last half of a can between the bumper and bottom lining of trunk all the way up to each side where my lights are.

More sound stays in the car which im loving, it sounds like im upgraded amps or subs with just $15 in materials, try this method first since its cheap and see where it takes you (It probably wont help fix the problem 100% but its a start to a long process of quieting a trunk lid).

Other than turning it down there is no generic answer but with some more info on what you have, how it is installed, what kind of car, some pics/vids etc. it gets easier to help.

Well it all the equipment is in my sig except I am running a BXI2610 instead of the RD amp. So for how it's installed, the sub is firing up and the port is firing back. So basically the sub is firing right at the trunk lid. I am thinking about rebuilding the box and firing sub and port into the cabin to help with it, since that should take care of most of the rattle I would think since the pressure would all be getting forced into the cabin. But basically with the design right now I am fucked so some of the closed cell foam kind of lessen the impact at all?

Great help. Please spend some time when you make threads to define what your goals are. Perhaps starting with the simple things even like what kind of car it is...

<--doesn't have sigs turned on which is rather normal here

Other than turning it down there is no generic answer but with some more info on what you have, how it is installed, what kind of car, some pics/vids etc. it gets easier to help.

Well it all the equipment is in my sig except I am running a BXI2610 instead of the RD amp. So for how it's installed, the sub is firing up and the port is firing back. So basically the sub is firing right at the trunk lid. I am thinking about rebuilding the box and firing sub and port into the cabin to help with it, since that should take care of most of the rattle I would think since the pressure would all be getting forced into the cabin. But basically with the design right now I am fucked so some of the closed cell foam kind of lessen the impact at all?

Great help. Please spend some time when you make threads to define what your goals are. Perhaps starting with the simple things even like what kind of car it is...

<--doesn't have sigs turned on which is rather normal here

Didn't know that you had sigs turned off. Ok here is the break down. It is a RE XXX 15 in a roughly 3.5-3.6 cube box before sub displacement. It is sub up port back running off of a BXI2610 in the trunk of a 2002 Grand Prix. My back seats do not fold down, unless I go get some 04+ grand prix backseats which I can modify the brackets and whatnot and make them fold down. All I have is a little section where the back armrest is that folds down and it is down at all times. What else do you need to know? 225 amp alt, kinetik 2400 in the rear. I just put two more layers of deadener on the trunk lid the other day.

Note: This problem only seems to be happening at night when it is nice and cool compared to the days. So I wonder if it happens to do with the metal slightly changing due to temperature variations. The trunk is nice and heavy now too due to the deadener, in fact it will not even stay open once you close it slightly.

Other than turning it down there is no generic answer but with some more info on what you have, how it is installed, what kind of car, some pics/vids etc. it gets easier to help.

Well it all the equipment is in my sig except I am running a BXI2610 instead of the RD amp. So for how it's installed, the sub is firing up and the port is firing back. So basically the sub is firing right at the trunk lid. I am thinking about rebuilding the box and firing sub and port into the cabin to help with it, since that should take care of most of the rattle I would think since the pressure would all be getting forced into the cabin. But basically with the design right now I am fucked so some of the closed cell foam kind of lessen the impact at all?

Great help. Please spend some time when you make threads to define what your goals are. Perhaps starting with the simple things even like what kind of car it is...

<--doesn't have sigs turned on which is rather normal here

Didn't know that you had sigs turned off. Ok here is the break down. It is a RE XXX 15 in a roughly 3.5-3.6 cube box before sub displacement. It is sub up port back running off of a BXI2610 in the trunk of a 2002 Grand Prix. My back seats do not fold down, unless I go get some 04+ grand prix backseats which I can modify the brackets and whatnot and make them fold down. All I have is a little section where the back armrest is that folds down and it is down at all times. What else do you need to know? 225 amp alt, kinetik 2400 in the rear. I just put two more layers of deadener on the trunk lid the other day.

Note: This problem only seems to be happening at night when it is nice and cool compared to the days. So I wonder if it happens to do with the metal slightly changing due to temperature variations. The trunk is nice and heavy now too due to the deadener, in fact it will not even stay open once you close it slightly.

It looks like you have done all you can for the trunk lid. Focus on easing the air resistance path from the trunk to the interior of your ride, as you want the "sound" in the passenger compartment - not wasted in the the trunk area.

JP