[PeteKz]

Originally Posted by dannobee

^^^THIS^^^

In all of my years of ripping and tearing apart interiors in high end cars for various repairs behind said panels, I've seen the progression of sound deadening. Modern cars more often than not use a small strip of heavy sound deadening in the middle of larger panels and strategically located smaller strips in certain areas, then combine that with a thinsulate type material on the backside of interior panels, and even then, the thinsulate rarely covers the whole inside of the panel, only strips or patches.

Short of breaking out the engineering crew, test track, dB meter and spectrum analyzer, I'd follow what most of the factories use.

I hear ya, but I think that works in modern cars to prevent large panels from vibrating and transmitting sound because the car makers have paid a lot of attention to eliminating noise at the sources now. "NVH" is now a critical part of testing and development in a car, whereas when many of our cars were designed, it wasn't.

I agree that you don't need to cover every square inch of most parts of a 911, such as the inside door panels, frunk panels, footwells, etc. But for the rear seat and shelf, so much noise comes from the engine and transmission and wheel wells and transmits through the metal body parts that it "probably" helps to cover those parts completely. I will also note that Porsche covered that area completely too (and the floor), presumably for good reason. Whereas, you don't find much sound deadening in the rest of the car.

Of course, without rigorous testing, I don't know for sure, but now I have to rationalize why I did it, right?