Don't be afraid of doing drywall work. Now that you have a new house, you get to do all sorts of fun projects.
First, air gaps will transmit sound very well. Bottom of door may need a sweep. If you have forced air heating, common ducts or returns can transmit sound (no easy fix for that).
Rockwool Safe N Sound is commonly used for your type of problem. After that, I can only think of the Quietrock --- pretty expensive stuff, actually.
Never heard of using cellulose for sound absorption - maybe it works. Very unlikely your drywall is 1/4" --- in all likelihood its 1/2". Remove a wallplate if you want to see.
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First, air gaps will transmit sound very well. Bottom of door may need a sweep. If you have forced air heating, common ducts or returns can transmit sound (no easy fix for that).
Rockwool Safe N Sound is commonly used for your type of problem. After that, I can only think of the Quietrock --- pretty expensive stuff, actually.
Never heard of using cellulose for sound absorption - maybe it works. Very unlikely your drywall is 1/4" --- in all likelihood its 1/2". Remove a wallplate if you want to see.
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