Effectiveness of dynamat on floormats?

[ladysmanfelpz 10+ year member]

Title.

So I saw on stingers website that they took some roadkill and placed the floormats over it and cut it to size so that the deadener was on the bottom of the floormats. Has anyone done this and how effective is this? I drive a 97 subaru legacy gt and it has quite a lot of road and wind noise. I do not want to do a full sound deadener because of cost/weight/time issues, but would like to decrease my road noise a little. So far I am thinking of getting wind deflectors for my sunroof and windows, dynamatting the trunk and doing the mats. Does this sound like a good lil upgrade?

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[Kangaroux 5,000+ posts]

If you want to reduce road noise, look up MLV and CCF. Standard deadener like dynamat is used to help kill resonances and calm down rattling. MLV (mass loaded vinyl) and CCF (closed cell foam) when used together can act as a very good sound barrier.

I highly suggest heading over to this site: Sound Deadener Showdown - Your Source for Sound Deadening Products and Information and talking to Don about what you need.

 

[ladysmanfelpz 10+ year member]

So how about the tiles on the doors and roof, and mats covered with stinger roadkill? Would this quiet my ride and about how much would this cost me?

 

[trumpet 5,000+ posts]

I think what Kangaroux was trying to tell you is that putting Stinger Roadkill on your floor mats is a waste of product. Deadener manufacturers don't always know the limits of their products, and so they show some suggested uses that don't really do anything. The goal is probably to add mass to the mat, but vibration damper(Dynamat, Roadkill, etc.) is very poor at adding mass. You really should contact Don at Sound Deadener Showdown.

 

[cyn 10+ year member]

Neoprene - Foam Insulation, Closed-Cell Foam, Neoprene Pads

ccl rubber works just as good as anything thats sold from CA sites

 

[keep_hope_alive Premium Member]

closed cell foam won't offer any benefit in terms of road noise reduction.

putting patches of material won't either.

increasing transmission loss of the vehicle skin is a complex effort. think of it this way - you need to add a liner in the car that is installed in such a way that it would hold water. and the liner needs a lot of mass - for this we use Mass Loaded Vinyl (MLV) in 1 lb/sq.ft. the install has to be continuous. any holes or gaps negate the effort (leaks). and to be effective, the MLV needs to be decoupled from the floor metal - that is where some foam or a rebound layer comes in.

even after covering the entire floor in MLV, sound comes in through the doors, door seals, glass, and anywhere you didn't put MLV.

it takes a ton of effort and MLV isn't cheap since it's sold in large rolls that cost at least a hundred bucks to ship the smallest rolls available. keep in mind we use this stuff in buildings and cover entire walls with it. smaller quantities can be had with Luxury Liner or Luxury Liner Pro.

adding decoupled MLV to the entire floor/wheel wells/firewall/trunk/roof/etc. and to the doors would certainly reduce road noise. Adding redundant door seals would go a step further. Replacing the windows with laminated glass would be the last step.

 

[keep_hope_alive Premium Member]

MLV sources

Mass Loaded Vinyl

Mass Loaded Vinyl~MLV~1 Pound~TMsoundproofing.com

https://shop3.mailordercentral.com/supersoundproofing/prodinfo.asp?number=09-00005-48

Mass Loaded Vinyl Barrier

if a product doesn't have TL testing or an STC rating, it's not an acoustical product designed to block sound.

the installation of any acoustical product is vital to it's performance.

 

[cyn 10+ year member]

MLV sourcesMass Loaded Vinyl

Mass Loaded Vinyl~MLV~1 Pound~TMsoundproofing.com

https://shop3.mailordercentral.com/supersoundproofing/prodinfo.asp?number=09-00005-48

Mass Loaded Vinyl Barrier

if a product doesn't have TL testing or an STC rating, it's not an acoustical product designed to block sound.

the installation of any acoustical product is vital to it's performance.

We have used Neoprene sheets in some of our shops for noise reduction... it does help a lot... we was using 1/2 sheets within the walls and dropped the noise levels by 30-40% I was going to use then in my old car before it got wrecked and plan on using it in my new one.

 

[keep_hope_alive Premium Member]

We have used Neoprene sheets in some of our shops for noise reduction... it does help a lot... we was using 1/2 sheets within the walls and dropped the noise levels by 30-40% I was going to use then in my old car before it got wrecked and plan on using it in my new one.

mathematically, 30-40% is a 1-2dB reduction considering we use logarithms to calculate sound reduction and halving source power is a 3dB reduction. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif subjectively, 30-40% would be about 4dB reduction as we perceive a 10dB change to be half/twice as loud.

MLV can reduce noise by 10-20dB.

this is what I recommend for shops when barriers are desired:

Noise Control Curtains | Model KNC

essentially they are MLV with quilted fiberglass absorbers.

a 1/16" neoprene rubber sheet hung in open air may have an effect on high frequencies, but lower noise (like road noise) would be mostly unaffected.

when adding it to a wall system it can decouple the GWB from the studs and then certainly increase TL of the wall. you'd just need to use it in strips on the studs. but don't confuse this with transmission loss of the material. that is a different property.

for GWB decoupling - even better results can be had with Green Glue products.

NOISEPROOF YOUR LIFE | Green Glue

 

[cyn 10+ year member]

mathematically, 30-40% is a 1-2dB reduction considering we use logarithms to calculate sound reduction and halving source power is a 3dB reduction. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif subjectively, 30-40% would be about 4dB reduction as we perceive a 10dB change to be half/twice as loud.
MLV can reduce noise by 10-20dB.

this is what I recommend for shops when barriers are desired:

Noise Control Curtains | Model KNC

essentially they are MLV with quilted fiberglass absorbers.

a 1/16" neoprene rubber sheet hung in open air may have an effect on high frequencies, but lower noise (like road noise) would be mostly unaffected.

when adding it to a wall system it can decouple the GWB from the studs and then certainly increase TL of the wall. you'd just need to use it in strips on the studs. but don't confuse this with transmission loss of the material. that is a different property.

for GWB decoupling - even better results can be had with Green Glue products.

NOISEPROOF YOUR LIFE | Green Glue

hmmm... Guess I'll have to look into some of that other stuff you have posted above here...

 

[ladysmanfelpz 10+ year member]

Ya so it looks like sound dampening is some tough work and my car is getting old and I don't think its worth the time and money to put that all in. I am going to give my car a good detail though, including pulling the door panels off because my windows are falling off their tracks most likely due to my cvx kicking back there. So I think I might get some CLD to apply to the doors and trunk as well, but I don't want to go overboard. I could always add more later, and/or do some MLV as well to really quiet it down. Whats the best route to go for this price wise? Would a dynamat doorkit be sufficient enough for my 4 doors and some of my trunk for my 97 subaru legacy? Would be buying local to support my local shop and I think all they carry is dynamat, but may have some other stuff as well.

 

[keep_hope_alive Premium Member]

to fully seal and coat the doors, 15-20 sf per door works well. 100% coverage on the outer skin, and 100% coverage/seals on the inside will reduce road noise from the doors noticeably. Dynamat is fine.

 

[ladysmanfelpz 10+ year member]

100% coverage on the outer skin,

On the outer skin? Do you mean the plastic door panel?

 

[keep_hope_alive Premium Member]

no, outer skin means inside the door cavity - on the outer skin.

my doors before

i cover 100% in two areas.

1. inside the door

2. on the face of the door

i encased fiberglass batt insulation in 1mil PVC

and secured it to the outer door skin for the entire surface area of the door skin (in 3 rows)

then I cover the large hole(s) with a panel (wood or aluminum sheets with deadener preferred)

 

[winkychevelle 10+ year member]

speaking of that fiberglass hows that working for you?