R&D Report 1994-14 : The sound insulations of studio doors: Part 1: Door Blanks G.D. Plumb, R. Clark The sound insulations of a range of different door blanks were measured. The results were compared with the sound insulations of existing BBC door blanks. The new doors were made from medium density fibreboard (MDF) which is more stable than the blockboard used in existing studio doors. Consequently, they should require less maintenance and adjustment and should have a longer lifespan. The doors had higher sound insulations for their weight than existing designs, which might permit savings in the costs of the surrounding building structures. Overall construction costs of the door blanks themselves are likely to be similar to those of existing designs. A companion Report (BBC RD 1994/15) describes sound insulation measurements made on plant-on door seals. The intention of this work was to simplify the construction of the door frame and the fitting of the seals to reduce costs.