The studio is 'soundproofed'.
a 'soundproof' room/studio
(..) I'm Xania. You do not know this, but I am intimately familiar with your work. You are very kind. Did you say that booth was soundproof? Yes. Now, you were nearby when Gluant was killed? Yes, I ran out to be with him after the team won. (..)2006 The Pink Panther
(..) a person yelling. Stop! Stop, stop! Who are you, and what the hell are you doing? - I'm in the middle of an interrogation. - The booth is soundproof. She can't hear a word. And in case you haven't noticed... ...you ruined my recording session. Now, get out. Unless you want to be charged (..)2006 The Pink Panther