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Mazda 3 Lover
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Discussion Starter · #1 ·
Hi all ,

just installed a heavy sound system in my mazda 3 and the trunk rattles a lot when driving and listening to loud music. can someone please help on how to eradicate those rattling sound? heard about dynamat but still don't know what needs to be done.
 

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Dances With Corners
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57 Posts
Well, that's kind of the problem with putting big subs in a car. Anything that can rattle will rattle, and over time more things will loosen and rattle.

I've never used dynamat in a car but I've used it in computers. It helps to deaden noise but it won't really get rid of the underlying problem, and of course it will deaden the sound overall which isn't really what you want in a sound system. I don't know of a magic bullet solution, beyond taking things apart and using locktite on all of the bolts and screws.

You might want to take a good look at the trunk lid, if that's what's rattling then that might not be so bad to fix. Does it rattle when you hold the trunk lid down? It might just be rattling the latch.
 

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The worst offender is likely the license plate. It’s only held at the top. You could start by removing that to see if it helps. Dynamat sells a product for that, but anything to stop the vibrating plate will fix it.
 

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i'm assuming you still have the stock head unit? how easy was it to hook up an external sub to it? I have a Bazooka bass tube powered sub in my truck and absolutely love it, was thinking of getting one for my 3 as well as the bass is rather weak.
 

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Mazda 3 Lover
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Discussion Starter · #5 ·
i'm assuming you still have the stock head unit? how easy was it to hook up an external sub to it? I have a Bazooka bass tube powered sub in my truck and absolutely love it, was thinking of getting one for my 3 as well as the bass is rather weak.
got it done by a pro. yes, had no choice apart from using the stock head unit. had to hook a DSP so as to have appropriate output to amplifier.
 

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Rubber side down
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272 Posts
Hi all ,

just installed a heavy sound system in my mazda 3 and the trunk rattles a lot when driving and listening to loud music. can someone please help on how to eradicate those rattling sound? heard about dynamat but still don't know what needs to be done.
Youtube.com is this cool web site that can show you how to do almost anything, even challenge you to eat stuff that could make you deathly ill (i.e. Tide Pods)! Search boxes are awesome! Clicky

There are other, cheaper options than Dynamat, some good, some not so good, and different densities to suit your application. Just have to do your research.


I can tell you that removing the upholstery in the trunk is cake. Remove all the interior panels, bump some music, and start listening / feeling around for rattles and vibrations. Process of elimination. You hear a rattle, put pressure with your hand where you think it is coming from and find what stops the rattle. Apply your MLV or 'tar mat' on and around that area. Or, if you want to get serious, buy enough to line the entire trunk area and just start laying it down. I can also tell you that the trunk floor is EXTREMELY thin sheet metal, so applying MLV to the bulk of that will definitely help keep the sound more focused and tamed. Remember that rattles can be due to two surfaces vibrating against each other OR a single surface vibrating like a guitar string or a reed. Feel for both those possibilities.

Once you have all your trunk vibrations taken care of, you may start to hear more in other parts of the car because you have now changed the overall acoustics of the car. Sound now moving more efficiently through the trunk may come through stronger in other areas. And remember, MLV is heavy (that is how it works), so if you are worried about adding too much weight, apply sparingly. Good luck and have fun!


Edit:

Just realized you posted that you had it done by a pro. Always a good option since they do it all day long. Next time, consider DIY. It can save you some cash and you get the satisfaction of solving your own issue and learning something new at the same time.
 
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