I build a “sound proof” room with double walls. On the inner wall I used 0.75” MDF, then special cock, then drywall. I also build MDF boxes around the air conditioner vents that ran through the ceiling. Packed the space between the walls with mineral wool.
It took forever and was super hard to work with. Hard to even screw through.
It took forever and was super hard to work with. Hard to even screw through.