Abstract: A leveling apparatus incorporated in the frame assembly of a sound-proof enclosure for assuring correct alignment of component parts of the enclosure, and a proper plumb fit between the door and door frame during assembly of the enclosure which is assembled on an uneven floor substrate. The leveling device including a leveling block secured within the base of a floor channel, the block having a pair of oppositely disposed tracks which run along a generally inclined plane. A leveling insert is secured within the door frame post and includes a leveling wedge threadably received along an adjustment bolt which runs transversely through the door frame post and the leveling insert for lateral movement of the wedge along the tracks of the leveling block for adjustment of the door frame within the floor channel of the sound-proof enclosure.