Sound proofing

Been noticing lately that my truck really seems loud on the highway. Just road noise, don't know if it's getting louder as my tires are wearing or if I am just noticing it more now. Either way would putting some dynomatting type stuff on just the doors make a significant difference or would you need to do the entire cab to really make a difference?

 

I used almost a box of Kilmat ( bout 65$ for 50 sq ft). Did all four doors complete and the back wall all the way down to the front seats. Still had a few sheets left over. Made a huge difference in the cab. cut the road noise down by about 50-75%.