Best put high density Rockwool between the studs

I have just put one up a stud wall on one of the bedroom walls, using
High density rockwool and soundsheild plaster board all bought
from Wickes.
I used small timbers 45mm square i think, with a slight gap to the
party wall.
The HD rockwool is simple to use, just cut to size with a stanley knife.
Don't know end results yet, as carpet is being fitted today.
Simon