Uh oh. My car smells like asphalt

**Rudy** · 05-02-2007, 05:18 AM

Originally Posted by IC-C30

roll on damper/deadner won't work on a large surface. deadening is about adding mass.... Those liquid deadeners are only good for hard to reach spots. or spots yiu cant use a mat on because of the shape.

I haven't really found that to be the case. Remember, you are going to be applying a liquid or paste at close to 2 mm thick, so it is a 3 dimensional material once applied.

In my experience, the best results are achieved by splitting the load - good quality mat covered with a few coats of good quality liquid. Works well and keeps things neat and clean. Then a layer or two of closed cell foam over the top of it all and you are set.

**nobb** · 05-02-2007, 10:51 AM

Thanks for everyone's input.

Rudy, do you think the liquid deadener might be strong enough to hold my Blueskin to the door (incase it might fall)? Maybe I could use:

http://www.partsexpress.com/pe/pshow...54&rak=340-270
or
http://www.partsexpress.com/pe/pshow...54&rak=268-250

to help keep my Blueskin on? I think I would still like to try the Blueskin route, since it only costs about $5/m^2 , whereas the other deadeners cost ~$20 to $30 per m^2. Thats not including shipping to Canada, which is expensive. Blueskin works just fine for me, but I just need some sort of adhesive to give me peace of mind that my Blueskin wont fall off.

Or does anyone have any recommendations for adhesives (type?) to keep my Blueskin on my doors? I am hoping for something I can get locally at Home Depot.

**Rudy** · 05-02-2007, 12:18 PM

Originally Posted by nobb

Thanks for everyone's input.

Rudy, do you think the liquid deadener might be strong enough to hold my Blueskin to the door (incase it might fall)? Maybe I could use:

http://www.partsexpress.com/pe/pshow...54&rak=340-270
or
http://www.partsexpress.com/pe/pshow...54&rak=268-250

to help keep my Blueskin on? I think I would still like to try the Blueskin route, since it only costs about $5/m^2 , whereas the other deadeners cost ~$20 to $30 per m^2. Thats not including shipping to Canada, which is expensive. Blueskin works just fine for me, but I just need some sort of adhesive to give me peace of mind that my Blueskin wont fall off.

Or does anyone have any recommendations for adhesives (type?) to keep my Blueskin on my doors? I am hoping for something I can get locally at Home Depot.

Neither of those would be good choices, but I don't think any adhesive will do what you want. If you use a good contact cement, it should hold the stuff in place until it gets soft enough to peel away deeper inside the mat. No adhesive will stop it from melting. People who use asphalt are PLEASED to have it fall off, since the alternative is so bad. You want it to fall off before it melts.

**turbocad6** · 05-02-2007, 12:32 PM

hey don, seems you really know what your talking about, I got a question...

there was another pro here once commenting on soundproofing, & he said something to the effect of dampenning a firewall with regular dampening materials can actually be worse than no dampening cause it will lower the resonant freq of the firewall & transmit more lower freq noise than before... does this sound right? I have bquite ultimated my firewall all the way to the windshield (dash out) & then covered with another layer of stuff that is like a foil backed padding.... I would like to make it even quiter & was considering going over it with a lead sheet to block more noise.... any input?

**Rudy** · 05-02-2007, 01:14 PM

Originally Posted by turbocad6

hey don, seems you really know what your talking about, I got a question...

there was another pro here once commenting on soundproofing, & he said something to the effect of dampenning a firewall with regular dampening materials can actually be worse than no dampening cause it will lower the resonant freq of the firewall & transmit more lower freq noise than before... does this sound right? I have bquite ultimated my firewall all the way to the windshield (dash out) & then covered with another layer of stuff that is like a foil backed padding.... I would like to make it even quiter & was considering going over it with a lead sheet to block more noise.... any input?

Thanks. I'm not scientist, but since I put Sound Deadener Showdown up I've heard from lots of people and have tried to learn a thing or two.

You really can't make a general statement about the impact of shifting a substrate's resonant frequency. Adding mass will lower it, stiffening will raise it, so sound deadener should have no effect at all

I've hear plenty of people making exactly that claim. What's being left out of their thinking is that both adding mass and stiffenig the panel require more energy to excite the panel in the first place.

The sound deadeners we use are going to lower the resonant frequency more than raise it, so it is possible to both reduce the total noise transmitted and allow RELATIVELY more low frequency noise through. These systems are so complex that anybody claiming exactly this or that outcome is not likely to be correct.

Lead sheets make fantastic barriers for noise. To really do the job, you need to issolate them from the substrate. In most cases, an 1/8" of foam will do the trick. Open cell foam is most often used, but if you have any concerns about moisture, go closed cell. Sound deadener covered with a thin layer of foam and lead sheeting should make a tremenous difference. Ideally, you'd want another thin layer of foam on top of the lead foil to soften reflections.

Remember, I'm no scientist, or real expert of any kind, I'm just very interested in this topic. I point this out again, because it is almost inevitable that somebody will question the wisdom of using lead in this manner. I used to share that concern until somebody pointed out that lead doesn't evaporate or otherwise become airborne and explained that it had to enter the body either orally or through direct injection into the blood. I haven't figured out how that could happen, but would be interested to hear other opinions.

**turbocad6** · 05-02-2007, 01:29 PM

yes, I always use a decoupling layer inbetween, ... when I'm ready to add a few hundred pounds to my vehicle I'll be lead sheeting the whole firewall & belly, thanks for the input

**nobb** · 05-21-2007, 10:36 PM

Sorry to bump a month old thread...but I have one quick question. You guys have finally convinced me..and I think I will get some eDead v1 for my front doors.

My question is...should I apply this to the inner part of the door (the side opposite of the exterior of the door, and is before the water barrier piece of plastic) as well? Silly question, but when I first took apart my door, I noticed that this area was very dirty, indicating that the outside elements had partial access to this area. If I applied eDead v1 here...would the water, dirt, etc have a negative effect on the eDead (like water soaking into the material and maybe peeling off)?

**Rudy** · 05-22-2007, 03:09 AM

Originally Posted by nobb

Sorry to bump a month old thread...but I have one quick question. You guys have finally convinced me..and I think I will get some eDead v1 for my front doors.

My question is...should I apply this to the inner part of the door (the side opposite of the exterior of the door, and is before the water barrier piece of plastic) as well? Silly question, but when I first took apart my door, I noticed that this area was very dirty, indicating that the outside elements had partial access to this area. If I applied eDead v1 here...would the water, dirt, etc have a negative effect on the eDead (like water soaking into the material and maybe peeling off)?

You should apply it to both surfaces of the door, if you have door moounted speakers. If not, you can get by with just doing the innermost surface you are describing.

When applied to a clean substrate, sound deadener is impervious to the elements - it's flashing tape after all.

**Abmolech** · 05-22-2007, 01:06 PM

I know this is old, but it is rather annoying misinformation.

A firewall is convoluted, principally for strength, but also to raise its resonate frequency (bracing). Adding mass will lower its resonate frequency, a blocker is the best solution here.

All panels vibrate, and therefore resonate. The audible of which is determined by your proximity and the SPL of the resonate.

A panel is either closed or open termination.

In an open termination the frequency will form modal patterns "moving" to the edge of the panel. If the panel size is small in comparison to the frequency length, the edge of the panel will sum, causing significant movement.
Possibly the best example in a car, if the roof with a centre mirror attachment. Yes thats why your interior mirror vibrates so much with bass.

Closed termination is where the edges are "fixed". The vibration (frequency) travels to the edges and is REFLECTED back towards the centre, were it sums (or nulls) depending on the frequency and the length of the panel. Best example is your tail gate, where you have a "signal device" Yep the number plate. Ever wondered why it is so difficult to reduce this signal? It is attached right on the SUMMING point of the panel. Putting dampener on the edges is wasting money, it will be useful near the centre of a panel (blocking advantages aside)
Using liquid deadener therefore in the corners, is only useful to inhibit rust.

Point
Small panels only sum at high frequencies. Putting dampener on them is to no avail. (a blocker might be useful however)

Use dampener on the middle of a door panel (outer)

Do yourself a favour and make a proper baffle for the door inner, that is, a blocker. Dampener has some blocking ability (that aluminium layer), I strongly suggest there are better and cheaper methods than using multiple layers of it.

**turbocad6** · 05-22-2007, 01:26 PM

ok, so this is my firewall, I dampened the whole thing with EVERYTHING removed, I then wrapped all of the ductwork for the a/c- heater box, & I then used a cotton padding & then the stock rubberized mat with a decoupling foam backing over the firewall....

I want to redo this because it's still not quiet enough, should I remove the dampening (b-quiet ultimate) on the firewall? & if so, where on the floor should the dampening actually start?