i built one, wood needs to be 2" thick to be even slightly soundproof, plasterboard (drywall) is best. two layers one each side of the 2" by 2" frame.
i built one here have a look at the door, it is larger than the door frame, it is made from 2 layers of 3/4" mdf and 1 layer of drywall in between, and taped at the sides with 2" aluminium tape. i kept the bottom frame 8" above the floor and sealed the entire floor with thick black plastic in case of hydroponic water leaks (downstairs neighbour), sealed the walls with white megalux plastic and totally sealed all joints. i laid two layers of drywall on top of each other on the floor and sealed my fans too, and filled every gap on the inside,
here is a handy sound guide check out section 5 and 6,
http://www.odg.org.uk/pdf/leaflet_6.pdf
some pictures :
1 the original bedroom door.
2 the inside room door.
3 the door larger than the frame.
4 the weather seal strip (tripled)
5 a normal cabinet hinge x 4
6 the acoustic fan ducting and home made fan box.
7 fan box.
8 8" rise above floor can be seen at the bottom.
9 gap between old room and new.
10 gap between sealed window box on left and room on right (wire can be seen leading to internal small 20w lamp inside window box).
11 gap between window box on right and room on left with duct leading from sealed window box to internal room,
12 outlet duct.
13 inlet duct.
14 fan before internal soundproofing stuffed in.
the locks on the door were a complete waste of time.
i had to design home made ones designed to pull the door tight against the seal when you lock it.
i will take pics later and post them here.
