Acoustic doors?

To reduce sound transmission you need one or more air spaces, this reduces the path that sound can travel through.

First option is two or three solid core doors where you create an air gap between each. I don't know your room or construction of your space so I can't elaborate on how and where to hang them.

I had a hollow core door on the utility closet housing our central AC unit. I replaced it with a solid core plus a fiberglass panel on the back and it reduced the sound enormously.

Upgrading the second door to solid core, the hall way door between the utility closet and my listening room removed all noise competing with the music.

Sound works the other way around too. Stopping it from going through to the bedroom is the same approach. Gaskets may be required if you have much space under the door and unless the walls are filled with fiberglass sheets like I've done in my room, the door may no longer be the transmission path after upgrade.

How much do you want to spend and how much sound do you want to stop? An opening as small as 1/4" between the two rooms will cause the sound to get through. Are aesthetics important? Most sound is stopped using gasketing that can be either surface mounted (cheaper) or concealed in the door. Phil Brady.

If Albert constructs his "air spaces" with concrete or lead, great! But the only thing that affects (reduces) sound transmission from one space to another is MASS and STIFFNESS, but primarily MASS, not xtra air spaces. I just love the myth that stuffing a stud wall cavity with fiberglas stops sound transmission, LOL! The only thing doing that will stop, are the screams of the little creatures that choke on the fiberglas ;-)

As for doors, 1-3/4" solid core (MASS) fully gasketed. with a welded steel frame (STIFFNESS) and no less than 1-1/2 pairs of ball bearing hinges (1-1/2 pair actually = 3 hinges ;-)
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