sound deadening vs sound proofing
Yeah ... did my research -> definitely not worth it.
Just to clarify, there is a difference btwn sound deadening and sound proofing. IIRC, applying deadener material, i.e. Dynamat, Boommat, Damplifier Pro, etc., or basically adhesive backed asphalt style sheet material, is a good way to reduce a panel's resonance potential - think turning a "ping" into a "thunk". In essence, you are changing the mass of the item you applied the material to and the "heavier" item now has a lower resonate frequency. Some could perceived this as noise reduction.
Yes, applying this sound deadener material in varying quantities in strategic locations (inside doors, on the roof, under the carpet) can reduce noise or vibration caused by speakers (bass) or road and wind noise (tire noise and road surface imperfections). This material can even reduce the hollow or tin sound of the roof when it is raining hard (our non-sunroof Touring is guilty of this). However, applying a sound deadener is only part of the equation.
To achieve ultimate tomb, "Cone of Silence" like quietness, you need to go one step further. Along with sound deadener, some companies offer sound proofing material in the form of closed cell foam and/or mass loaded vinyl. (See link provided at bottom). These products, are designed to actually absorb sound waves and make them less audible. An example of this would be a bad guy in a movie using a pillow as a gun silencer when he/she needs to knock down the sound of the gun shot. The pillow absorbs some of the sound and makes the shooting less "noticeable"...okay, maybe not the best example, but close enough.
The combination of both the deadener (usually over applied in gross amounts) and the sound proofing materials will ultimately give you a quieter interior. If you choose to go down this road, you will have to be fully committed and do your homework.
There are liquid version of these material that can be sprayed in places, like the wheel wells and underside of the passenger cabin AND in more serious cases, inside the cabin during full rebuilds/interior stripping.
I think even some folks have reported positive results by applying paint on bed-liner products to their wheel wells. In fact, I know of a person in AZ that coated his entire car (Audi A4) in bedliner and he said the road and wind noise dramatically decreased inside the cabin. I'm not saying you have to go to that extreme, but it is just one example of how applying certain materials with certain properties can change the way noise enters/does not enter the cabin.
Some car come with (small) amounts of deadener in the floor, roof, and rear panels, but it is often not enough to achieve the "Lexus" like quietness we would love to have, yet not own a Lexus. Luxury cars often double, triple or quadruple the sound deadening/proofing material that regular cars have.
http://store.secondskinaudio.com/products/
- Not an endorsement, just one more option.
good luck. Cheers. (cheers)