Measure the area where the chamber will go. The best place is down the short wall of a basement. Cut the lengths of the 2-by-4s as needed.
Place the top and bottom of the wall frame flush together. Measure and mark the top and bottom placement of the wall studs on the top and bottom perimeter of the frame. Mark three-quarters of an inch back from the 16-inch mark to ensure the placement will be on center when pacing the sheetrock on either side of the walls.
Line up the outside of the narrow side of the framing square ruler with each mark. Using it as a guide, draw a line on both sides of the frame perimeter. Mark an "X" in between each space. The framing square ruler is the same width as a 2-by-4.
Nail the vertical 2-by-4s to the marked spaces with an "X" perpendicular to the frame perimeter. Place two nails at the top and bottom.
Screw the sheetrock to the frame that will be the inside wall. Ensure that the screw head doesn't break the sheetrock coating. Coat the wall with multiple layers of plaster and let dry. Apply a layer of high-gloss latex paint.
Screw 2-by-4s the width of the chamber into the floor joists 16 on center. Screw sheetrock to the 2-by-4s to create a ceiling, applying the same plaster and paint coating as the wall. There should be enough space to nail the wall when it is raised.
Mark a chalk line where the edge of the wall will go. Apply construction adhesive near the line. Raise the wall, firmly setting the bottom of the frame in place on the adhesive. You'll need assistance to help raise the wall.
Nail the top of the wall frame to the edge of the ceiling 2-by-4s. The sheetrock should be flush with each other where they intersect.
Cut a hole that will allow access between two studs near a far concrete wall.