Sound deadening Material on the Cheap.

I have gotten alot of ideas for sound deadening on this site which is great but i wanted to see if anyone has used the pad that goes under house carpet? The reason I ask is because I am currently finishing up 2 projects. Installing a console and hardwood flooring in my house. So i literally have a ton of the padding sitting next to a duster without carpet...

Its about 1/2 inch or less thick and is actually somewhat dense.

Anyone try this? I was thinking maybe using some of the dynamat type material first and then gluing down some of this padding on large flat areas.

What do you think?