Thread on sound insulation?

dan_b

dan_b

A2OC Donor
Help! I'm trying to find and read a couple of threads I remember reading in 2008 where one poster has been experimenting with adding in additional sound insulation to the A2 with impressive results - some particularly well-placed deadening material into the wheel arches etc? However every search I do just comes up with the same 22 pages of results.

Can someone more skilled than me at searching dig the theads up for me?

Sorry for my ineptitude

Dan
 
Thanks Brett - have you done any additional sound insulation to the A2?
If you were to suggest the first thing to do that makes the biggest difference to road roar, what would you do? Matts in the wheel arches?
 
sort of.

I've done too much in parts to really say "this is best"; a sheet of butyl in each arch helps, as does two in each door, some stuff in the doors... I want to do sludge on the wheelarch liners and the floorpan. My boot is still open at the moment, but when that's full, it's pretty damned quiet.

I'll get back when I've done some more. What I'd suggest: as Dr. E wrote, the outer door skins, the inner skins, some on the floorpan and the roof last.


What I've done:
- 1 sheet butyl per arch (I wanted EPDM, too, but it won't fit)
- 2 sheets per outer door skin, closer to 3 per front door
- 1 sheet of 2.5mm 5kg/m2 EPDM per footwell
- 1 piece of 4mm 7kg/m2 EPDM per boot side

- 1 l Noxudol total on the door inner skins.
- some B10 (closed cell) in the doors / outer panels - they are ALL now dead, apart from the bonnet.
- deadened the tailgate with butyl / noxudol / B10.

The boot floor will become pretty dead (material not sure, maybe stone); the door cards don't have any weight at the moment, the leather will make a difference too. The driver's footwell isn't done, nor is the firewall or the dash. Both need something.
I'll probably try and butyl the lower trim parts if I leather them, too.

Bret
 
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Hi Bret - I'm definitely interested in the "sheet of butyl" in wheel arches as a first step.

Would you be able to advise on what spec I need/ who sells it, and also how to fit?
 
Dan, if you do, I'm interested in it as well. I've been in EFMAX's car, it is remarkably different, noise wise. Even by shutting the door, it sounds like the door of an A8/S-Class with a deep 'thung'. Inside, with nothing running, I can tell it already blocks out much of the ambient noise.

I want to do the doors and wheel arches. If time permits, the dash as well. Engine noise is inaudible below 1200rpm but gets a bit loud as it revs to 3k. Well, at least it doesn't sound agricultural ;-)
 
Need to find out where to buy this sort of stuff?
Cool maybe we can work together to fit it to both of our cars, seems you're not that far away from me :)
 
caraudiodirect has "max mat", Spectrum Sludge (for the floorpan - or at least that's what I'll be using it for), and Luxury Liner. The LL is kinda expensive, so you can get some acoustistop from studiospares, which is better value. Overkill is quite good, if you can find some "splen 3008", that's also very good.

If you're taking the wheelarch liners out, make sure you have a supply of the -300 pop rivets. Push the center in to the first click AND NO FURTHER and you can reuse them. I used 8 on all four arches.
You will also need to remove your mudflaps if you have them.

Fitting's pretty simple; cleanup, cut to size, press on.
Pick up at least two small packs of maxmat (or a "bulk pack") and see how far it gets.

EDIT: if you haven't already, go check out the movies in this thread: http://www.a2-freun.de/forum/showthread.php?t=31301 before you buy anything. It shows you how easy it is and the effect :)

Bret
 
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wheelarches: Outside some butyl (so that's one - two sheets @ 25x30cm)
inside, under the carpet, the acoustistop on top of a layer of butyl would be the ideal way, depends on the space available, my carpet's already tight, but 4mm should be possible.

The two have different functions. The butyl stops the resonance, the acoustistop limits noise transmission.
That's why the butyl makes the doors go "dump" instead of "clong". The Acoustistop is you best friend when we're talking about limiting road noise.

Mine is now actually seriously quiet if the boot's full. Quieter than the wife's 307, I know that, and cruising at 50mph it's perfectly possible to have a quiet conversation. That's with spikes :D

In an ideal world, you stop the vibrations with mass and elasticity and then something very dense will reduce noise transmission dramatically.
Make sense? If you then fill the space with foam, the remaining noise can't really move anywhere, meaning the insulation is even more effective.
If you wanted to go the whole hog, the doors could get an additional layer of foam behind the cards, which again helps. This thread - http://www.a2-freun.de/forum/showthread.php?t=24459 - is from a dealer, which explains why it's quite so comprehensive. But it's a very good reference.

Your 4sqm should get you a lot of the way round the car, depending how much you splurge.



Bret
 
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Butyl is the component; MaxMat, Dynamat and Damplifier all contain it.

Quoting from www.sounddeadenershowdown.com:

Butyl with a non-asphalt filler.

Products in this category match a butyl base with a non-asphalt filler to add mass. The mats I tested have a higher butyl content than the butyl with asphalt mats and are therefore more expensive. Second Skin Damplifier, Damplifier Pro and Dynamat Xtreme fall into this group. I'm also looking forward to samples being sent by Cascade that have similar properties.

These are the elite sound deadeners. They have the heaviest aluminum foil constraining layers and are the most expensive to manufacture. They have heat tolerances significantly higher than any of the other products I tested, with the Second Skin products having the highest tolerance of all. If your mat is going to be exposed to extreme conditions or if you are willing to pay more to squeeze that last bit of performance out of your efforts, these are the mats for you.
Click to expand...

I tend not to use product names as I can't at work, and it really doesn't make *that* much difference if you're comparing MaxMat, Damplifier or dynamat unless you look at the price. The ingredients are very similar and the function too.

Bret
 
Thanks this is going on my list of things to do. Might get some to do my loft bedroom too try and block out some of the plane noise!
 
if you have space, the best thing you can do:
- from the outside, start with a thin layer of insulation
- then acoustistop over that
- then an airspace
- then the final layer of insulation with your boards on top.

If you've already got a finish, then acoustistop, 100mm rockwool, and some airspace with your new wall on the top.

The principles are pretty simple, the main issue is that to stop long bass waves you need something pretty "massive" in the sense of dense and solid. Butyl sort of helps, because it weighs 3.3kg/m2 and that contributes to the weight addition, but its main function is to stop vibration / panel excitation. The Acoustistop is the stuff that really drops the noise level.

Bret
 
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