Reducing NVH

[freebeard]

Thank goodness for search engines: en.wikipedia.org/.../Noise,_Vibration,_and_Harshness

I haven't used Dynamat[-like materials], but from the installation videos, it looks like the progression from a little to maxed out goes like this: Picture each panel as a drumhead, start with a patch in the middle where it vibrates most. Then cover it completely. Then add a second layer.

I agree with pursuing wind noise. My Superbeetle has good weatherstripping, but the new weekly driver, the Dasher, doesn't.

My back seat is folded down, I think the reverberation is increased.

In addition to the firewall and floor, inside the doors and in the roof (under the headliner?) are good areas to cover.

[wdb]

Originally Posted by oldtamiyaphile

Second thing I realised about sound proofing is that you'll always be limited by the car's glass, most of the noise in my Renault comes in through the large areas of glass, sound proofing the rest of the car is of little value, unless you have a specific problem.

This is true. A small, light car may well have thin, light glass. Luxobarges have thick glass solely for the purpose of reducing noise ingress.

[freebeard]

Luxobarges have thick glass solely for the purpose of reducing noise bullet and shrapnel ingress.

[BLSTIC]

I have found that in all of my hatchbacks with folding seats interior noise increases (dun dun dun...) DRAMATICALLY when the seats are flat. And even more that one time I had occasion to remove them. In the rain with the seats down you can hear individual droplets hitting the rear wheel arches, it's like you have exposed metal. Oh wait...

I also noted that car with more exposed plastic are louder, caves with rough walls are silent, and concrete hallways echo endlessly unless they have carpet.

Also I found this book that is explaining a link between interior surface and cloth, but the most fun tables are wiped out (cloth vs leather sound absorption). Data implies a 1dB reduction for a cloth seats over leather.

https://books.google.com.au/books?id...0level&f=false

So I would say:

1: Make sure all your seats are upright and the tray tables are stowed away (for minimum plastic area)
2: Fluffy seat covers are win (if you can strap them down properly)
3: If at all possible, cover large hard areas with something resembling carpet.
4: Flock your dash

This will provide the most compliant (for absorption) and roughest (for dispersion) surface over the most area on the inside of the vehicle

[ar5boosted]

On an older car, I wouldn't hesitate to use a lot of [find the fireproof type - that won't catch fire] Spray Foam to achieve body deadening.

https://www.youtube.com/watch?v=uloK98jMTGY

On these older cars, they were made from tin-foil. The foam has a bonus value of being impact resistant. So it would be advisable to use in bumper bars and side doors to improve impact protection.

[freebeard]

https://en.wikipedia.org/wiki/Fuzzy_dice

Aftermarket sound absorption modules. (This example hanging on a clothes line, those are clothes pins)

[BLSTIC]

Originally Posted by freebeard

https://en.wikipedia.org/wiki/Fuzzy_dice

Aftermarket sound absorption modules. (This example hanging on a clothes line, those are clothes pins)

Those are nice, but they aren't available in the correct size. You really need to invert them to get it to work

[freebeard]

No eating in the car!

They could lose the white door jambs.

[oldtamiyaphile]

It's been missed in this thread, but the best thing you can do for noise is fit an airdam.

[hispanicpanic]

Originally Posted by oldtamiyaphile

It's been missed in this thread, but the best thing you can do for noise is fit an airdam.

Where do you fit the airdam?