Trunk Sound Deadening - Dynamat, Damplifier, etc.

[dsp4848]

Just curious if anyone has used any time of sound deadening material in the trunk? If so, what was your experience?

My car is a DD and when taking road trips, rough roads can be quite loud in the cabin. Not a huge deal really, but I'm interested to see if adding any sound deadening material would make a decent difference.

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[VTECSAUCE]

I was actually thoroughly impressed at how well sound insulated the car is. I find myself constantly rolling the windows down to hear my exhaust. I have roush mufflers and an x pipe so its not quiet. Having said that, on the high way with no music I can hear slight drone.

 

[VinnAY]

Having done it one another car, the change was negligible at best. That's rubberized undercoating, three coats on any metal in the rear. Not worth the time or cost, and undercoating spray is the lowest cost option.

 

[Dramad1]

Rammat is really good stuff and half the price of dyno mat. They also carry ensolite for dampening.

 

[MikeD1]

I was thinking about doing this in my car, then I put in one of those heavy Lloyds trunk mats & a lot of the noise quieted down.

 

[Texstang]

Not sure if this is 100% related to your issue, but I think there was a post in one of the forums where a member used a rubber mat to create a barrier between the jack and the tire well.

Found it:
Link to thread

As for soundproofing, it can work, but if you're going to do it, this website has a pretty good explanation of the materials and process. Looks like it would be a weekend job, but from what I've heard from someone who followed a process similar to this, it's worth it.

 

[gundam83]

Not sure if this is 100% related to your issue, but I think there was a post in one of the forums where a member used a rubber mat to create a barrier between the jack and the tire well.

Found it:
Link to thread

As for soundproofing, it can work, but if you're going to do it, this website has a pretty good explanation of the materials and process. Looks like it would be a weekend job, but from what I've heard from someone who followed a process similar to this, it's worth it.

Go to sound deadener showdown read up on the science about it. Basically if you're sole purpose is to block out road noise, skip the CLD material (Dynamat, Damplifier, etc) as that is just to reduce panel vibrations, which probably won't be an issue with the anemic stock sound system. Get massloaded vinyl with closed cell foam and create a barrier between the noise and yourself. I personally used Luxury Liner Pro which is those two materials combined into one product.

 

[DropTop66]

The drone at cruising rpm from my new Gibson cat-back system on my 2015 convertible was driving me crazy so I read up on vibration and sound insulation hoping to tone it down and keep the exhaust system. The entire trunk was covered in Boom mat first as well as portions of the rear quarter panels in the trunk area. Closed cell foam was applied to TMS Mass Loaded Vinyl cut to fit each surface and was applied to every surface, wall and the entire tire well. A panel 'sandwich' of a layer of CCF and MLV, then 1/8" hardboard and another layer of CCF and MLV was constructed to fit behind the back of the back seat, completely closing off the trunk from the interior. Well, after all that time, expense and added weight (Boom mat & MLV aren't light), it made virtually no difference in reducing the drone or even quieting the road noise, top up or down. Just my experience with this stuff, perhaps others have had better results, but I wouldn't waste my money again.

 

[gundam83]

The drone at cruising rpm from my new Gibson cat-back system on my 2015 convertible was driving me crazy so I read up on vibration and sound insulation hoping to tone it down and keep the exhaust system. The entire trunk was covered in Boom mat first as well as portions of the rear quarter panels in the trunk area. Closed cell foam was applied to TMS Mass Loaded Vinyl cut to fit each surface and was applied to every surface, wall and the entire tire well. A panel 'sandwich' of a layer of CCF and MLV, then 1/8" hardboard and another layer of CCF and MLV was constructed to fit behind the back of the back seat, completely closing off the trunk from the interior. Well, after all that time, expense and added weight (Boom mat & MLV aren't light), it made virtually no difference in reducing the drone or even quieting the road noise, top up or down. Just my experience with this stuff, perhaps others have had better results, but I wouldn't waste my money again.

From my understanding, real drone isn't just a noise that sound deadening can treat. You want to get rid of drone? Change your exhaust. Taken from another forum:

What is it?
Drone is the word to describe a resonance phenomenon that offends nearly every type of material on the planet as a specific frequency range.


What causes it?
This sound frequency range is typically between 133 - 138hz for cars. This frequency sends the energy through the metal frame, body work, and everything in between (even seats in some cases) and shakes the molecules creating an awful humming sound.


What can I do about it?
Not much. You can't really block this frequency range because it is a natural resonance frequency. It will rattle EVERYTHING (even materials like wood and some softer materials as well). Dynomat in your trunk won't work. Dynomat on your floorboards or on the unibody underneath your seats won't work. This range of 133 - 138hz is incredibly difficult to manage. The best way to address drone is with muffler design or resonators. The factory mufflers are specifically designed to not only block but also CANCEL these frequencies. Some aftermarket designs such as Borla's and Corsa's offerings do the same job. Borla's design cancels out some of these frequencies as well as ensures that the sound energy is going out the tailpipes. Corsa's designs have an internal chamber that is of the correct length to cancel this frequency out using the laws of wave reflection.

 

[jgedde]

Just curious if anyone has used any time of sound deadening material in the trunk? If so, what was your experience?

My car is a DD and when taking road trips, rough roads can be quite loud in the cabin. Not a huge deal really, but I'm interested to see if adding any sound deadening material would make a decent difference.

I've Dynamatted my spare tire well. Noticeable decrease in road noise inside the cabin...

John

 

[DropTop66]

gundam83: I had read the article which you quoted among various others. Since I like the sound of the exhaust system except for the drone, my intention was to stop or reduce the resonating of the metal panels with the Boom mat and then to isolate what remained with the CCF decoupler and MLV. Not to dispute statements by those with greater depth of knowledge on the subject of causes of exhaust drone, I have experienced times with the top down when there was a substantial reduction of the drone while cruising under the exact same driving conditions, i.e., gear selection, same road and grade, engine rpm, constant throttle, etc. The only variables I could cite were that day's temperature and wind direction and speed. Sounds nuts but it is what I have experienced. So I thought I would give the vibration and sound proofing a try before giving up on the exhaust system.

 

[pinero61]

I did the entire floorboard, trunk, seat delete, and doors with Dynamat superlite. I also did closed cell Dynaliner on the doors and seat delete. The difference in road noise and exhaust drone was staggering.

 

[DropTop66]

Just an update about that Noico self-adhesive closed cell foam.

https://www.amazon.com/Noico-Insula...76069332&sr=1-6&keywords=noico+sound+deadener

The adhesive melts right off of the foam when used in the trunk in the summer heat, and I'm not talking about 100° days either. After installing the Boom Mat I cut pieces of MLV to fit the contours of the entire trunk. Then I cut and adhered the Noico CCF to the MLV and placed that on top of the Boom mat, foam side down. A few weeks later when I went under the access panel I found that I had pools of gooey, sticky adhesive in the well of the trunk. (The adhesive is clear but looks black in the photo.) Several hours later I had most of it cleaned off the stuff in the trunk well and the floor itself with mineral spirits. What a freakin' mess!
The description at Amazon says it can be used in places up to 212° but I have a hard time believing that the trunk floor gets to that temperature with expressway driving on a 92° day.

 

[dsp4848]

Just an update about that Noico self-adhesive closed cell foam.

https://www.amazon.com/Noico-Insula...76069332&sr=1-6&keywords=noico+sound+deadener

The adhesive melts right off of the foam when used in the trunk in the summer heat, and I'm not talking about 100° days either. After installing the Boom Mat I cut pieces of MLV to fit the contours of the entire trunk. Then I cut and adhered the Noico CCF to the MLV and placed that on top of the Boom mat, foam side down. A few weeks later when I went under the access panel I found that I had pools of gooey, sticky adhesive in the well of the trunk. (The adhesive is clear but looks black in the photo.) Several hours later I had most of it cleaned off the stuff in the trunk well and the floor itself with mineral spirits. What a freakin' mess!
The description at Amazon says it can be used in places up to 212° but I have a hard time believing that the trunk floor gets to that temperature with expressway driving on a 92° day.

Haha, wow. I hope other people look at this before they decide to go with Noico. Sorry to hear about the mess, but thanks for updating.

 

[BmacIL]

Just an update about that Noico self-adhesive closed cell foam.

https://www.amazon.com/Noico-Insula...76069332&sr=1-6&keywords=noico+sound+deadener

The adhesive melts right off of the foam when used in the trunk in the summer heat, and I'm not talking about 100° days either. After installing the Boom Mat I cut pieces of MLV to fit the contours of the entire trunk. Then I cut and adhered the Noico CCF to the MLV and placed that on top of the Boom mat, foam side down. A few weeks later when I went under the access panel I found that I had pools of gooey, sticky adhesive in the well of the trunk. (The adhesive is clear but looks black in the photo.) Several hours later I had most of it cleaned off the stuff in the trunk well and the floor itself with mineral spirits. What a freakin' mess!
The description at Amazon says it can be used in places up to 212° but I have a hard time believing that the trunk floor gets to that temperature with expressway driving on a 92° day.

Sorry to hear about the mess! That sucks.

As far as drone goes, change the exhaust. I used to have a very low drone system, but one that was boomy in the cabin still. I've now got a Corsa and there is zero. You can't even make it drone, even a little bit. They're pricey but absolutely worth it.

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