A pillars revisited
Almost 3 years have passed since I did the last step in the deadening of the 406 Coupé. I'm revisiting the A pillars to test some new products to use.
New products for sound deadening
Dynamat Extreme is an amazing product, it blocks heat, noise and adds mass to the panels to stop them resonating. No vibration, no noise. This is great for lower frequency noise , but higher frequency noise that is air borne still goes thru. So you need something that can trap that kind of noise and this is done with foam or something dense.
I opted for Dynaliner to apply on top of Dynamat Extreme to reduce this type of noise. I found some polyethylene low density foam that is used in homes to lower noise on laminate flooring, usually from impact. It doesn't absorb water and it's quite light, it's perfect to fill the hollow areas in the A pillars for example and it's very cheap. It's the first product I will be using not made for automobile use.
A pillar revisited
The A pillars had already been deadened, but were the perfect place to add these new products to reduce the air borne noise.
Since the A pillars are hollow and have multiple layers of metal inside it was the perfect place to add some polyethylene low density foam to fill them up. Since the A pillars were already deadened I had to remove the Dynamat that was applied covering the access holes. It was a good thing that it was a hot day, it was very hard to remove the Dynamat from the metal, I can't imagine removing it on a cold day.
After applying the foam it was a question of putting the Dynamat Extreme back in place in a little extra layer to keep it in place. The A pillars are now filled with foam, from the dashboard to the headliner.
I also applied some polyethylene low density foam where the front tweeters are and on some parts of the dashboard near the front window.
After this Dynaliner 1/8" was added on top of Dynamat Extreme and on some areas of the A pillar trim to remove any hollow spaces were sound could travel.
Driving on the highway there isn't a big difference about the wind noise. True, on the A pillars there is no noise passing by, but I still get wind noise in the front door windows. The big difference was in the music coming from the tweeters, the sound stage is now more defined. This is something I wasn't really expecting.
Done in 29 of June, 2010