Hi 

having upgraded the front speakers in my superb to a pair of Jl s I was pondering fitting some sound deadening in the doors and wondered if any other members have tacked this job and if so which type of material they found effective 

Have a look at this thread from Wednesday from about the 5th post onwards: Improving Audio / Sound Deadening

Did changing the speakers help much?

 

Certainly the replacement speakers give more detail but the mid bass is still not great I am going to put sound deafening inside all four doors and will report back