Materials that soundproof structural noise from new wall to another

[hermelinen]

Hello,

I am going to build a new wall in my space to divide the room, and the wall needs to be soundproofed.
But what type of material should I use to ensure that sound waves do not transfer to the other wall it is attached to, as well as the ceiling and floor?
Wooden studs will be used.

While I'm at it, I have another question about soundproofing: Does it make any difference if I use, for example, Roxwool Flexibatts or if I use something like Isover Piano?

Thanks in advance.

 

[anaitis]

You should have gypsum in large amounts.
Filling in the wall insulates very little against sound.

 

[hermelinen]

Yes, I know, but I need something that absorbs sound waves against other walls. Which rubber should I use?