sound deadning not working in trunk

[obsidian]

I have an 18 in my mazda 3 2012 trunk firing up ported. I have 4 to 5 sheet of Hush mat on my trunk lid but it is still flexing loudly on the 18 turned up. Is there anything I can do to fix this or is this just the nature of the beast when having an 18 in your trunk

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[bradl79 10+ year member]

Prob get better deadener. I used 80mil audio technix and I love it

 

[k3n12ock 10+ year member]

Expanding foam aka great stuff

 

[calebkhill 10+ year member]

Is it the lid or another area of the trunk?

 

[Popwarhomie 5,000+ posts]

Sound deadener can only do so much. An 18 firing right at the trunk lid is going to makes rattles no matter what brand or how much you use.

Fire forward/port forward and seal off the truck.

 

[obsidian]

Is it the lid or another area of the trunk?

it is the lid. HushMat came highly recommended. I only used 1 bulk pack for car. I am using 4 to 5 pieces on the the trunk lid. The expanding foam I dont think will work well in that location because there is carpet there and behind that is the metal. I dont know if the carpet will go back on. I can only think of just putting more deadening which is thicker or something like bradl79 said

 

[obsidian]

Sound deadener can only do so much. An 18 firing right at the trunk lid is going to makes rattles no matter what brand or how much you use.
Fire forward/port forward and seal off the truck.

i agree. The port is firing back and sub up. So fire port forward? Sub can only fit firing up. **** i might just throw it in back seat and call it a day.

 

---------- Post added at 03:18 PM ---------- Previous post was at 03:17 PM ----------

 

Ill check it out thanks. Ill google it

 

[Popwarhomie 5,000+ posts]

How big is your box for the 18"? There is a reason most people don't run an 18 in a trunk car. Not enough room to run the proper box. 2 12s firing forward sealed off would probably be louder than your 18 firing up. Plus you wouldn't have rattles.

 

[dbeez 5,000+ posts]

There is an outer skin and inner skin on a trunk lid you need to put expanding foam between them prior to deadening to make that gap solid not it will make it quieter but whne you get really loud or fire an 18 right at it no matter what you do short of welding the trunk lid shut will stop it from jumping around but you can kill 90% of the horrible rattle noise.

 

[obsidian]

How big is your box for the 18"? There is a reason most people don't run an 18 in a trunk car. Not enough room to run the proper box. 2 12s firing forward sealed off would probably be louder than your 18 firing up. Plus you wouldn't have rattles.

yeah your mostly right. just wanted to try something different. I am very happy with the 18 decision I just like the sound. It hits deep notes effortlessly. I like too much bass which is where I am. It was also a price thing. it is loud enough starting to hurt ears. box is probably 4.5 cubes ported within specs of the obsidian 18. Box is great doing its thing. Its the car thats not. I dont need anymore volume but the its obvious you lose all sq when the trunk is making that sound. I have seen cars back in the day where the whole back of the car shook with the bass tones from the shear BL but not a noisy vibration. But it is an 18 and you are clearly right. But I was seeking an alternative solution for the rattling while keeping the Obsidian

 

[obsidian]

There is an outer skin and inner skin on a trunk lid you need to put expanding foam between them prior to deadening to make that gap solid not it will make it quieter but whne you get really loud or fire an 18 right at it no matter what you do short of welding the trunk lid shut will stop it from jumping around but you can kill 90% of the horrible rattle noise.

yes i see your point. inner and outer of the metal of the trunk lid . Hmm I have to check that out. Thanks!

Just found out installer did use expanding foam. Oh Well !

I am still happy !

 

[obsidian]

Going with the foam solution tonight. Installer says it should be much better. I was think attaching some lead bars to trunk to keep it from flexing lol. We shall see.

 

[CHEMMINS 10+ year member]

Lol.....deadener is not for flex. Foam will help. But for actual flex, you are gonna need to do more work than that.

 

[obsidian]

Lol.....deadener is not for flex. Foam will help. But for actual flex, you are gonna need to do more work than that.

Yeah i agree. I was thinking lead bars at first lol. Then I was thinking some sort of brace or springs to push the trunk lid up when close idk. You got any creative suggestions? I can't really turn the system up and it sound clear at all.

 

[obsidian]

Foam in interior panel and trunk lid did the trick for the most part. Super loud jeezy songs i get some rattle but huge difference. Thanks for everyone's help