Went to the market today and came across a few interesting materials available locally and pretty cheap too.
This first one seemed similar to the sound damping sheets, it was also quite heavy and thick. I believe if the principle is to mass-load the surface in order to reduce the metal flex, this might do a pretty good job. It had no sticky material on it and the shop keeper said you lay it on the surface and apply some heat on it for it to stick. He said people frequently buy this from him for car floors. They called it "Daamar" and it was Rs.400/ft.
^ This second one is a closed cell foam jumbolon sheet with a layer of aluminum on it. It was 10mm in thickness and Rs110/ft.
^ This one's an 18mm jumbolon sheet without the reflective layer. It was also for 110/ft. These jumbolon sheets were available in multiple thicknesses.
Now I was thinking whether we could do a combination of these i.e. the black sheet in the first picture and the aluminum 10mm jumbolon sheet for the entire car floor, for hard to reach areas we could just apply the daamar sheets. How effective would it be? Or maybe we could even do a combination of stinger roadkill and these sheets, e.g. stinger on the door outer sheets, then jumbolon on the inner, jumbolon plus black sheets for the floor, and only black sheets or roadkill for the wheel wells.
Goal is to have a final outcome comparable to, if not better, I had the complete deadening done by the stp or stinger materials with much higher costs.
Any help or input from the experts would be highly appreciated.