Measure the walls and ceiling dimensions in the recording studio. Calculate the wall and ceiling area by multiplying width by length, and determine how much foam mattress padding you'll need to purchase to cover this area.
Purchase foam mattress padding from a furniture shop. Foam can also be purchased in a large hardware store, cut to measure.
Purchase a foam-and-fabric spray adhesive in a hardware store or a fabric shop.
Spray one wall at a time with adhesive, and lay the flattest side of the foam mattress pad against the wall so the textured side is facing out. Press firmly on all areas of the mattress pad to ensure it's adhering. Consult the spray adhesive instructions for more details.
Apply the foam mattress pad to the remaining walls and the ceiling. Use a ladder when applying the padding to the ceiling.