yes, but you shoudl do it yourself. Most installers assume you won't be pulling your carpet.. and won't take the time to do it right.
If you don't heat it up and apply correctly... it will not dampen as well as it can.
It's been awhile, and there amy be tons of new stuff since I was an installer... but back when i was installing, Super Dynamat was the bomb. I would use a few layers of that, then use the dampening spray over it.
That was before i cared about weight though...