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Discussion Starter · #1 ·
I have a bunch of raamaudio bxt and ensolite, as well as the car basically gutted (for a car pc install). What seems to be the verdict ont he most effective deadening in the 3? I'm not really interested in covering the thing like some do -- too much time/energy -- but I'm more than willing to spend a roll of each on some key areas. I will do the doors completely but what would be the second and third things to do? I assume the hatch area and a few of the bigger spots on the floor? How about the roof, kickpanel areas, firewall, etc?

Thanks for any tips -- looking to maximize the benefit for the amount of time/money I'm going to spend on this.
 

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There is probably not a lot of differences in sound quality between products. They will all deaden vibrations effectively. Some are thinner and have to be applied in more layers to get the same effect, but the thicker products may not leave room for the door panel to be reinstalled as easily either.

There is some difference in how easy these products are to work with. One brand has a slow-setting sticky that allows for pieces to be adjusted during installation, and then later firms up to stay where you put it, which sounds like a good idea to me. Others are very, very sticky so you have to get them right the first time. I have read of complaints of glue losing adhesion on a few products.

Which product is the best bang for the buck right now, I can't say. I just did my doors, which are about 80% of the problem, and for those it hardly matters how expensive the product is because it took about $50 to do both doors very heavily in one of the more expensive products. I don't use the rears, so it was only the front doors that needed damping. A cheaper but equally good product would have been maybe $30 instead, insignificant in $700 total installation.

The asphalt and asphalt/butyl products are not very heat resistant, and can slump off the panels in the sun. Make sure you use an all-butyl product.

I try to avoid using any product using vinyl, since it is a toxic chlorinated hydrocarbon that creates huge pollution problems during the production process and also off-gasses pthaltates used to soften during its lifetime.
 

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Sound/noise control is something I have been studying looong time. I hope I have something I can share here.

First of all, let's make your goal clear.
Is your goal mainly -improve audio/speaker sound?
or- make vehichle quieter??
Well, these two kind of come along together but depend on what you are aiming, there would be different focus point to maximize efficiency.
 

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BTW,,is this thread in right category..? ( it seems more like Interior Mod??) I would like to keep discuss about this, just wanted to make sure.
 

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Yeah should be the right spot for this.

I have already coverd the whole car with 2-3 layers of mat (dynamat extreme, fat mat, other misc liners) only because I had so much and had the time to do it. Foam filler in the pillars and neoprene sheets on the roof, just about covered it. I dont drive a racecar and only about 1 mile a day on weekdays so weight issues isnt a problem. Road noise is gretly cut out and keeping the sound in has been improved but nothing like I wanted it to be for as much work that has gone into it. There is always room to improve but im done with this one for now.

The most effective areas would be the doors and floor (enire floor from firewall to rear of car). Headliner not so much of a difference except for SPL issues with the roof vibrating.
 

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ok, I guess I can go ahead and post more about deadening here:)


Well.. I hate to start from saying that most effective noise control (road noise) was changing tire but it was true.. I am not sure if US market dealing DNA dB, Regno like comfort tires, but these ones are just another level when it comes to road noise.

Sorry for out of main topic. Let’s go back on deadening talk.

I would like to keep topic as deadening/damping as I can, but need to mention about that to control noise in vehicle, there are important 3 categories.
VIBRATION CONTROL—prevents noise cause
INSULATING—block noise
ABSOBING—absorb noise

Because the way you control vibration (deadening/damping) gives different way of insulting and absorbing.

For simple example, if you damp center of some larger panels (quarter panel, door panels..etc.),
This will drastically reduce vibration volume by damping material (butyl rubber + binding layer<aluminum>---DynaMat, RealShield), but it can shift vibration frequency to the lower range (this sometime can cause more uncomfortable noise pressure to some drivers even though overall noise levels are lower.), which is harder for absorber to kill, insulator to block this low frequency sound wave and need to select denser and thicker material to counteract this control. It is ok if you can put 30cm of insulator, absorber materials in your car, but there is only limited space to work on.

On the other hand, if you bring noise frequency higher (which is very hard to control) using such as Nitto Hard (heat reactive foaming epoxy + aluminum cloth) on the panels,
increasing spot welding points, thinner sound absorbing materials can handle its range efficiently. But this will probably out of what we can try DIY level. So let’s put this aside.

Important thing is what,where and how to apply deadening material which we can easy to obtain efficiently.

First few names I can come up about deadening/damping materials are

(butyl rubber + binding layer<aluminum>)
DynaMat
RealShield

(sound damping paste)
Noxudol

First two are pretty common and easy to use deadening material you can get. Since these are butyl-based product, it is not highly stable against where lots of heat can be.
RealShield is slightly lighter and thinner material but damping effect is almost same.

Generally it is said if you cover 2/3 of panel area, it will give enough damping effect and any more than that, probably just adding weights. I cover like less than 1/5 of each panels
only where damping effect is preferable though.

I used RealShield on part of front/ rear door panels, quarter panels, and the edge of roof panel. And for larger panels, I applied Noxudol sprayed about 2mm thickness.
For doors and roof, I insert 7mm thickness of Thinsulate Acoustic ( for door, between inter trim and inside panel.)
Also behind speakers, layout RealShield Diffusion to prevent bass loop inside of door shell. This made speaker bass sound very clear without spending tons of money for nicer speakers

About floor, there are already very thick compound mix rubber damping under floor and some asphalt sheet on the floor, there are not much place I can efficiently add damping.
I sprayed Noxudol overall just to make me feel “I did something”
Instead of spending damping materials on floor, I used construction sound insulator( rubber with dense compound) and 2 different compression rate PP felts.

Order of each materials are

------carpet
------high compressed PP felt
------low compressed PP felt( thinsulate acoustic 10mm)
------rubber insulator
------Noxudol
------asphalt sheet
------floor panel
------compound rubber

Insulator materials on floor basically blocks and reflect back outer noise( road noise, wind noise) especially from under floor.
And compressed felt(absorber) reduce noise power which insulator couldn’t block as well as noise which happened in the cabin. The reason I laid felt right under carpet is that if I put insulator material right under carpet, there is no noise escape for inside of cabin noise to escape/absorbed and can cause noise loop in cabin. (This is what I learned from Lexus noise control design. It is just unreliably well controlled in LS, GS. They even are selecting different vibration character panels for RH and LH or some opposing panels to prevent certain noise frequency to build up or counteract each other. Also nearly about 10-15% of vehicle weight is for insulator, noise control materials)

In the trunk room, I could put lots of absorbing materials to make trunk room noise escape and absorbing compartment. I went to junkyard to get good condition insulator, absorber from other high-end vehicles.

After all of these (I actually have more place worked…maybe mention another time when my finger can type more..lol), although floor work did make ok improvement, nothing made bigger difference than changing tires..
 

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Discussion Starter · #7 ·
Thanks for the thoughts everyone. Given that I'm just kind of going for bang for buck in terms of time spent and general improvement in both noise and sound quality, I think I'l end up focusing on the doors, a few panels here and there on the floor, the main hatch area where the sub will be, and then throw some felt down because hey why not, its cheap.

Thanks!
 

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upashi, your right about the tires.

Its a shame the reason I worked so much on this to keep the noise levels decent, my tire/wheel/ even rotors make most of the noise. Cheap drilled/slotted rotors with a bit of warp make the most annoying sound with a thin sidewall with overly aggressive tread wrapped around 18" wheels.

Then add noise from a modded exhaust. Alot of noise.... :shock:

I had a few cans of what one company calls Quiet Kote from Cascade. The one I had was another brand with a little more thickness to the coating, (probably what is called Noxudol from what upashi said?) and fumes to kill most if not all i had left of brain cells which having the car stripped for a few days made it able to work with. That stuff worked great for coating hard to reach places or to go under some of the places where the panels met together.
 

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I know..after I changed my tires...I kinda realized what indivisual DIY can do ..lol
I mean, even with conflict between cost cut and noise control, of course maker try to perform best and had most efficient treatment as much as they can. So I guess we only can try supplimental noise control to cover where mazda couldn't spend money on.

Well, unlike Lexus, Mazda3 should have still lots of place we can try and enjoy working on. Even if we can't get best result, that fun part of DIY too:)



Noxudol info..

Noxudol has many different product from anti-rust coat to sound damping coat.

The one I used for interior is Noudol 3100. It is a waterborne viscous, elastic sound damping paste based on polymer. Due to its viscous elastic flexibility it converts sound producing resonance into heat. ( I believe solvant inculdes little ammonia,,not too stinky but it's stinky enough for a day or so..)Very mild though..lol
it's light gray past when wet, and once it dries, they are light beige.

Also I used another Noxudol product called Auto Plustone ( black tar looking paste) for my tire house and some underbody treatment. This product is used in Volvo's OEM underbody treatment line. It also conform elastic rubberized coat and has very superior protection agaisnt rust as well.
 

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[quote author=upashi link=topic=139800.msg3014201#msg3014201 date=1237915697]

After all of these (I actually have more place worked&#133;maybe mention another time when my finger can type more..lol), although floor work did make ok improvement, nothing made bigger difference than changing tires..

[/quote]

Any idea of how much improvement (dB) after all that? I would figure that the windows become the weak point after the tires and some deadening/barrier is used. Know of any window treatment that actually reduces noise? I know they use laminated glass in quiet home windows.
 

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I honestly don't know how much db in what condition exactly dropped..( >_<)
hopefully even with placebo effect, I want to wish it got quieter lol
I wish I have easy db tester access and comapre vehicle..
But when I changed tires from stock one to DNA db, interior noise at 40mph dropped from 70.2 to 69.3 ( 0.9db drop) on asphalt street. ( microphone was under grove box space)
Windows are the one will be waek spot for sure. If you are looking for reducing noise from window, probaly need to ask glass shop to custom laminated glass and also need to custom window regulator( rails)and reciving channel as well. Which mean,,,too much work and money.( >_<)
 
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