New Carpeting, Installation - Need Padding? Options

[kliney30]

Got a quick question for those of you that have installed new carpets...is there a need or rather a benefit of installing padding underneath the carpets to deaden some of the road noise? Or, would this not really benefit much given that the majority of the noise comes from the enging being directly behind the seats.

Has anyone installed carpets with padding or felt that it's necessary?

Evan

[TonyAKAVW]

I think it was SirAndy who reccomended the idea of applying sound deadening material to the carpet backside. I thought about this and while it saves you from rust I suspect that the sound deadening effectiveness is severly reduced.

The reason the sound deadener works is not because it absorbs sound (though it does that a little) its because it changes the resonant frequencies of the metal. More imporantly though it reduces the 'Q' or the intensity to which the metal will resonate at some particular frequency or frequencies. If the sound dampening material is not applied to the surface, the reduction of Q will be totally dependent on how forcefully the carpet/deadener is held against the metal. Gravity probably won't do much. Now if what you are applying is a sound absorber (these are often some kind of foam/rubber/tar sandwich material and MUCH thicker than the roll on dynamat, etc.) then you might gain something. I'm not sure how long it would stand up to the abuse that carpet gets, so who knows.

I think the best bet if you want a quiet car is to first make sure that all your seals are good. This keeps rushing air out, and water too. If you maintain the seals the car _shouldn't_ leak.... Then, strip the interior down to metal, repaint with POR-15 using the right method, and then lay down the dynamat over that. The areas that create/transmit the most noise will be large, flat areas of thin metal, not strucutural elements such as the longitudinals. This is basically what the factory did, and does in most cars. The problem with rust is due to poor maintenence, not to the existence of sound deadening materials.

As for me, I recently stripped down the interior to metal, and POR-15'd it, but I haven't decided whether or not to put in anything to make the car quiet.

-Tony